Great video. Used this to work on my son's 2001 S10 with the 4.3. It had a P0300 that I was chasing. I had the engine out to replace front timing chain cover, oil pan gasket, intake gasket, and rear main seal. Replaced all plugs, wires, cap and rotor, they needed to be done anyway, did not cure problem. Pulled the distributor, and the drive gear was done. Replace distributor, all is good. Your video on getting things lined up saved me huge amounts of time and aggravation. 2001 timing chain cover has two marks, one at about 1 o'clock the other at 4, with #1 at TDC, lines on harmonic balancer line up to both marks in cover. Again, awesome video, thanks for taking the time to save us DIY'ers lots of time.
Justin, Considering the entire cost of the repair was under $400 I hardly think my customer got taken. Now, had YOU done the repair which would have been more than twice that, then he would have been taken, single injector replaced or not- plus my customer now has all new injectors so doesn't have to worry about this happening with the others which are of same age and exposed to same conditions like he would with your fix. But I still thank you- because it's guys like you who keep me thriving.
Brother, I can't thank you enough! I blew the intake gasket and replaced it.. Tried to cheep out and reuse everything... Through lots of codes and now I've replaced plugs, wires, pressure regulator and distributor setup. Got it all back together again and I throw p0300. I'm going back in to look better at the spider. This will help! Funny how happy we are when we find something that's broken!
mrpeables It's indeed fun to find what is actually broken, but it is only successful if you do it without replacing things that weren't broke. The thrill is in the diagnostic and knowing you were in control and owned it through the process. Glad you adapted to the correct way now.
Hey, your videos have been very timely for me. I have four Blazers and one S-10. One of the Blazers blew a manifold gasket and filled the crankcase with antifreeze. We have that fixed now and are putting it back together. One of the things I needed to do is reinstall the distributer. I came across your video on that, which led me to this one. Very informative! Your explanations are very clear and concise. Keep it up!
I've got a similar problem on my 1998 Oldsmobile Bravada. It will occasionally misfire under load and bring on the SES light. The last time it happened was when I turned the A/C on while driving down the road. These videos will be very helpful to figuring this problem out. Thanks so much for posting them.
Awesome videos on this. I love how meticulous you are, and how you methodically go through a diagnoses. Got a $500 03 s10 4.3l in beautiful condition with only a couple minor problems. Fixed everything so far for 250 bucks, now trying to figure out the intermittent rough idle.. Drove it 600 miles so far, the CEL flashed for about 5 sec while at 70mph. I quickly slowed down and it went off and stayed off. Hasn't come back on since. Pulled the code, p0301, #1 cylinder. Pending code.. Going to finish doing all these tests and narrow down the issue. Thanks again.
You're a godsend, a decade later and this is the only reliable resource I can find for this problem. Only difference being mine just dumps fuel into cylinder 3 but I imagine I'm gonna be pulling that goofy spider out of there soon.
if it’s dumping fuel into the cylinder you will want to make sure the transistor is not fried and permanently grounded. check for a short on injector 3 first- if it’s shorted you definitely have high risk for blown transistor.
Ah. I've just listened to your brilliant explanation. So all this time i could have had the 2 lines lined up but that could have been exhaust stroke... better than any mercruiser titled videos. Bless you
Goof presentation and a nice piece of experience plus logic. I am now Just driving my first non carburetor vehicle. This is for me a good look at the similarities and the new chunks.
Cylinder #6 was going into hydrolock due to the injector being stuck open with a piece of spider o ring. Popped the plug disconnected the coil and added nylon plug in coil for added safety disconnected injector power. Spun engine with starter and out came the fuel. Tomorrow we will have the new spider and all should be well. Thank you again for cogent, logical, coherent and useful content. Another favorite of mine is Wranglerstar channel. You will no doubt enjoy his work as well. Seeing him rebuilt an old one horse IH was good fun. Jk
Excellent John. Not to scare you but you will want to be sure that you still "pulse" at the injector wires for that #6. If an injector shorts out, the transistor in the PCM is basically sending 12V right to ground with no load or resistance. It can definitely fry the transistor- basically a new PCM. If you put a new spider in and #6 Still is always stuck open, then you will very much need to verify if the PCM has been shorted. Conversely, if you do find the PCM has shorted, never install another PCM until you are sure you alleviated the short. Was it really a shorted injector or is the ground wire shorted to the frame instead of being controlled by the PCM? Catch my drift?
I bought a 97 astro van that had this issue but it had the original poppet at the cylinder set up. turned out when the previous owner replaced the fuel pump they refilled the tank with several cans of fuel. one which was full of leaves. I ended up replacing the pump and flushing the lines . disassembling all the injectors and disassembling all the feed lines and poppets. 3 and 5 had nearly 125 pounds of air pressue on them when they finally came loose. I soaked everything in acetone got all components clean and have had no issues with it for around 8 years now. about every 8 tanks full of gas I will throw a cup opf marver mystery oil in the tank and it seems to be keeping it all working well. good vid.
@Spelunker and 12VGS- You guys are too kind! Thanks for the feedback. Actually, 12VGS, I'm a scientist (molecular biologist actually) but really, troubleshooting any problem uses the Exact same scientific method as curing cancer does. It's all a matter of proving one single cause is responsible for an observed effect and countering all other possible explanations that would refute your position.
Thanks for the great instructive videos. I have recently replaced the intake manifold gaskets on my 1999 GMC Jimmy 4.3 Vortec with 178000 miles on it. History of the process is I snapped a manifold bolt on re-assembly as my torque wrench was not clicking so i kept wrenching until I snapped the bolt. Well I had to disassemble the manifold and was able to cut a slot in the top of the bolt that was sheared off with a dremel and some fine diamond bits, I could then walk out the broken bolt with a flat bladed screwdriver. That made my day a lot brighter. I then went out and bought a new set off manifold bolts as recommended by my Haynes manual and other sources. The first assembly I just used the original bolts after chasing the threads with a die and cleaning out the bolt holes in the lower manifold with a tap as also recommended. Getting bored yet? On the 2nd reassembly I did not use a torque wrench as I was afraid I would repeat the bolt shearing so I just snugged the bolts in sequence til they were a nice pull. Specs for final torque is 11 ft. pounds which I thought was light but that is what the specs are. Any way I got it all together and it ran good for a day or so then I started getting a skip and a DTC code po3o6. Flashing ses light and the whole bit. I noticed that if i let it cool down for 8 hrs or so it would run fine for about 10 or 15 minutes and then it would start to skip and throw the same DTC code, but after a few days of that it now starts skipping as soon as i start it whether it is cool or warm, not intermittent anymore. As of this post I am still trying to find the problem. We have checked spark, changed plugs but not wires, replaced the distributor cap and rotor before the first reassembly, but took it off and inspected it as part of the diagnosis. The egr tube would not break free of the fitting when i took the manifold off so i thought i would cut the tube in a spot that i could re-assemble with some heating duct metal adhesive tape, which i did on re-assembly. However the night it started to run rough we inspected the engine and noticed that the tape had come off and the tube was opened up, so we fabricated a tube splice with some aluminum flashing and some small hose clamps, no change but after it cooled overnight it ran fine til it warmed up and the skipping/dtc code returned. i then coated the fitting tube and hose clamps with grey high temp RTV thinking I still had a vacuum leak there still no change. I have now purchased a new egr tube which i should be getting in a few days. Any thoughts on this would be appreciated. I am wondering about the spider injectors now after watching your video but i would probably look into the egr system first. Anyway i am a confirmed subscriber to your channel and will check you out as one of my first go to guys now. Thanks again and give me your thoughts.
When you said, "Getting bored yet?" I laughed and kept reading. :) Thanks. I'm not sure how to help you except on one point. When you did one of your repairs I noticed that you said it still had the problem? After a repair always reset the computer. Sometimes, including EGR repair, once it's seen broken by the car, it'll keep compensating for it after the fix. Until you reset, you won't know your current situation. It helps me learn even if I'm replying to an old post, so I hope you comment back!
DE Nichols Glad I made you laugh. Anyway it turned out to be the injector plug harness was not seating fully . I had to remove the plenum and scrape out the carbon from around the opening that the injector housing comes up through. It was not letting me seat the plenum down all the way. i cleaned everything up and lubed the gasket with some silicone grease and put it back on and she dropped in and seated down ,then I was able to plug in the harness and snap lock it in. I couldn't do that before and it was sporadic intermittent connection so that the injector was not always firing giving me the rough running and the flashing code. Since then all has been good knock on wood. ;-{)
Whenever I find one little connector undone that changes how the whole car is running I've exclaimed, "but I didn't even work on that part of the car!" ... hope I got a laugh back. :) Oh memory is fickle. I changed my spark plugs so often that I had to get a tap and die set for the bolt that holds the spark plug coil in place. A little tip for you. I get maybe 60k miles on my iridium plugs and while I was only getting 12k on platinums.
Thank you so much for this instructional video. This helped me out a great deal. I actually enjoyed viewing this. Please keep up the absolute best and very professional videos that you post for all of us mechanics. Again thanks for all the great information.
Hey man! Thanks for this and your other informative videos. It's really helping me to diagnose similar problems on my vehicles. I ruled out spark on my Dodge Magnum 2.6L V6 (but changed the plugs anyways because of their age) for my misfire problem and (unfortunately) it was a fuel injector issue. Thanks again! (PS I have a PhD in computational chemistry, so your systematic approach to diagnostics resonates with me)
Thanks for the methodical way of diagnosing the problem and pin pointing. My 1998 Chevy pickup I just bought had the same code pop up, P0305. My cheap scan tool had misfire number 5. So now I know what to look for.
I had been chasing this problem for a while never had a misfire before doing some maintenance on my truck. Installed a new spider on my 5.7L k1500. After a 1500 mile round trip I got a check engine light. When I put my scanner to read it said cylinder 5 misfire. Checked compression all was good installed new coil, wires, sparkplug and distributer and it continued to run like crap. Fuel pressure was good at 55psi. I never thought it would be the new spider I installed. I said the hell with it. It's a PITA but went ahead and removed the intake again and installed a new spider. It became a very expensive job since the old/new part didn't have warranty and walla engine sputtering went away and have not gotten a check engine light anymore. Horrible design makes me want to install a newer vortec 2001 and up just for the easiness of diagnosing and servicing of those engines.
Thanks for this man 😊. I bought a 96 s10 a couple years ago. High mileage, kind of a lemon. 😏 You know what they say, in for a penny, in for a pound lol. I've always run old carburetor vehicles, so this is the newest, and most problematical vehicle I've ever owned. That being said, these vids are gold 👍😁👍.
@90 TegTurbo- thanks for finally clarifying the injector replacement issue, your explanations sounds accurate and is probably why there was such disagreement on that. You are also, technically, correct on the diagnosis being done "backwards" as far as the fuel pressure check however remember this video is basically a sequel to another video where indeed this test was done correctly as you indicated.
Thanks for the video, I am now more confident in my diagnosis. I have the same vehicle experiencing the same issue minus the low fuel pressure. I ran through the same checks prior to checking the fuel injection system. I am going to get under the hood this week to fix the problem.
Sorry for the delay, I just realized you had replied. I ran the code and received a P0305 misfire on the number five. Spark test was ok. Checked spark plugs and wires and they were all but shot. Some idiot who had the car before me put in the wrong spark plugs without even properly gapping them! Before I go on I should say I bought this 2001 Jimmy for $700, so any money I put into was fine by me. Anyways replaced the plugs and wires, distributor, and the fuel injector system. Once I was down to the fuel injector I decided to replace the head gaskets since I was having some leaks. Had the ICM tested and it was bad too. Still haven't got it all the way together yet as I have been driving my other car.
Schrodingers Box When my new distributor is fully seated it is 3 degrees off of the six mark. Is that enough to cause a crank but no start condition? I have checked spark at all 6 plugs. Good. I replaced the spider fuel injector. Fuel is getting to the injector. Please help. Mark Jumper
if you're referring to the fan tool it's a Lisle Fan Clutch remover tool- don't have the part# but you can buy it at any NAPA store. If you're referring to the scantool it's Autotap which unfortunately has been discontinued.
Very good information on troubleshooting and I learned something with the spider injectors. One thing to consider is the spark plugs. I have replaced two different spark plugs because there was no spark even though there was a spark going to the plug. Ohming showed that they were open.
An open spark plug was ruled out using the spark tester. I have never heard of an open in a spark plugA how would that even happen?? I have seen cracked plugs many times but an open seems impossible.
Hi , I really like your approach to problem solving. Your scientific background really shown up in here. It is refreshing to see logic being used in car repair. Your explanations of the underlying physics helped greatly in understanding the complex working relationship of the car design. The information you provided here and on the other video about long term / short term fuel trim were excellent. I have a similar problem on a Subaru outback 2001 2.5 manual transmission and would like to get a few leads from you on where I should look as I am reaching dead end and don’t know what else to check. Problem: CEL code P304 - Cylinder #4 misfiring detected - The misfire cannot be detected by sound or feel only reported as code. Engine runs smooth with good acceleration. What I have done to isolate the problem: Ignition 1. Replaced wires and spark plugs - No change on code 2. Swapped Coil Pack with one from a good vehicle - confirmed terminal 4 have good spark - No change on code 3. Replaced valve cover gasket, spark plug gasket - No change on code ( a Subaru mechanic pointedto some leaks at the spark plug gasket and said that it was the problem and want to charge $ 300 for the job) Compression 4. Measured compression of cylinder 2 and 4 they both read ~155 PSI Fuel 5. Swapped Injector 4 with 2 ( both injector actuated with low voltage applied on work bench) - No change in code Electrical/ control 6. Replaced alternator - Battery voltage was 11.9 volts with engine at idle - Tested at auto zone indicated bad Alternator. No Change on code 7. Replaced ECM - No change on code (thinking that perhaps the driver of # 4 injection was faulty - i know swapping was bad but i was stuck with no new lead) Air 8. Conducted smoke test and Starting Fluid test and found no vacuum leak 9. Measured Vacuum in the manifold and it reads 15 inHg (in the red lateing valve timing zone of the gage) I need some of your logic to figure where to go next. Is there a correlation between low vacuum and Cylinder 4 misfiring? Vacuum Is common to all cylinder why would it cause only one cylinder misfiring? For only cylinder 4 to misfire, the cause should be related to single branch of the circuit. So perhaps 1) fuel rail to Cylinder 4? (4 and 2 share the same fuel rail), or 2) Electrical connection to injector 4 ? is there any things else? Any lead would be greatly appreciated.
The one thing you overlooked is CONTROL to injector 4. Swapping the injectors would only test if you had a bad injector. You need to confirm there is voltage at the #4 harness when the computer commands firing of the injector. That's what I would do next. You can do it with a noid light or even a DVOM.
I have this exact problem. Getting code 4 cyl misfire but vehicle does not misfire. New fuel spider, new plugs, wires, distributor, distributor spine. Compression test ok. One observation, if any other spark plug wire is pulled the misfire of 4 will stop?? 2002 Chevy Astro van
Great video! Still driving my 1996 chevy blazer. 365,000 miles! Lol just replaced the fuel infection spider and many other parts. Only code left is misfire p0303 on cylinder 3. Having a very hard time figuring it out. This will help.
awesome video....very detailed and straight to the point...a master mechanic you are for sure..made me a subscriber...thanks for the help and now Im gonna follow your steps to repair my chevy s10..
Thanks for the video, Very helpful. Just wanted to ask how you would check the original spyder injection system that does not have the wires going to injectors. With continuity check as you did for a short in it?
I took out the crank sensor and it looks worn. Its scratched and i can feel an invention in it. The mileage on the vehicle is almost 200,000. If the crank sensor is no good, could it cause an intermittent spark or no spark at all? Previous owners also just changed the timing chain.
thank you so much for this video. my mechanic has changed everything electrical out from plugs to wire to the distributor. nothing checked in the fuel system and i started wondering about that. i have an '02 Chevy S10 with the 4.3 Vortec and im getting a P0306 code and have been getting it over and over, starting to get really frustrating but im sure now its a fuel thing. thanks!
Very well explained video I just installed new engine and new spider injection in my 98 Chevy truck I've been having random misfire motor has 1000 miles on it. I've replaced every sensor there is re checked my timing and firing all is dead on my next step is to do as u have done on spider injection although it is new still leaning towards this may be a defective part. Thanks for the video
Ha, thanks Eric (great screen name btw!). I don't mind constructive criticism but when it's from people who either never turned a wrench or are professional "parts changers" challenged by a DIY, i guess I tend to get a bit fueled up. But these videos are for people like you, not them so maybe I shouldn't even pay them any mind. Thanks for your support!
Your test on the spider pack to test all 6 poppets at once... Can this be done without removing the intake? Or does the whole spider sit below/inside the intake?
Thanks for the advice. I did confirmed the connection of Fuel Injector 4 by connect an oscilloscope between one terminal of the injector and ground as well as using a DVM. DVM read 14 volts DC. Scope shown pulse width which increase frequency with increased RPM. I also used a stethoscope to listen for the ticking sound of the injectors. It sound the same as those in injector 2 and 1. do you know where I should look next? I just ordered an PC based reader that have trace capture. It will come non Friday and I hope to monitor it to see when misfiring happens. could you advice on which sensors or parameter to monitor. Many thanks
The injector assembly you removed is in fact the updated version. You CAN now purchase single injectors from NAPA and other part stores. But the fuel pressure issue also definitely needed to be addressed. This is the unfortunate case where the car needs two separate repairs. Can be hard to explain to the customer.
I was commenting about something similar on part I. I had a buddies car which diagnostically had 5 bad components. You hope as you go as you replace the other bad parts that the issue will be resolved, but sometimes you just know you're going to have to have the friend/customer except one loss at a time before its "all better". I took him through what was wrong one at a time so he's a satisfied friend, but it was a lot to swallow and months of him making more money to fix the next thing. I'm just grateful he didn't lose another motor mount while solving the issues that broke it. Phew!
HEY YA MATT THANKS FOR THE TIPS I HAVE BEEN HAVE THIS PROBLEM WITH MY 2003 CHEVY SILVERADO 4.3 L VORTEC MIS FIREING AND CHANGE OUT EVERYTHING GOT GOOD COMPRESSION BUT HAVE TO CHECK FUEL SURE ITS THE FUEL FROM WHAT YOU HAVE DONE I HAVE DONE SO IM IN TO IN SIDE
no have done everything and its the fuel spider just like you said matt and ordered it be here monday and installed thanks for all the pointers and yes alot of know alls but your the man and your info to the letter matt again thanks so much for your help again my system fuel pressure was 32.lb
I have a spark tester just like the one you use in part 1 of this video. I've got a constant miss on #2 and #4 (On 5.7L Vortec). Does the intensity of the light matter? Number 4 was very dim but consistently lit. Number 2 was brighter at times and showed less misfires on the counter on my scan tool than number 4. compared to #1 which was brighter consistently. Thought for sure I had a spark probably and replaced the only non new parts and put new wires on and there was no change. What about a intake water jacket leak into the intake? That would probably show up on the plug though. Going to the store to see if I can get a fuel pressure tester and at least check that.
Parker Waite Great question Parker- one of those that makes me wish I brought it up in the video. Yes the intensity of the light is proportional to the output of the coil-- er, I should say the output to the tester (the coil need not be at fault- high resistance in the wire could cause it too). In the event of suspecting a weak spark I will verify with another tester you have seen where can create an adjustable gap in the tester and measure the spark distance. Not sure if water in the intake causeing wet plugs would affect this- to verify it would be simple though- connect your light tester directly to ground instead of the plug. if it is brighter, then you have some evidence to support that, particularly if you swap the plug with another known good one (or dry it off).
Well i mean as a general possibility to causing a miss. So if i just put a test lead to ground instead of to the plug it may be more accurate of a reading? If i do have weak spark at ONLY 2 and 4 then that means wires, or cap and rotor. (Which are all new within the last couple months) A faulty coil wouldn't produce good spark on 6 cylinders and bad spark on 2.
Ah I wasn't aware of your model of car- I was thinking it may be a COP but even so it is possible a wire with high resistance could be responsible for weak spark on just one plug even with a distributor system. Anyway, Parker- answer to your question- not only is water leak into the cylinder a possible cause for misfire- it is actually the probable cause for it.
Schrodingers Box Well the frustrating part is the fact that it's got a new distributor assembly as of a couple months ago and i put new plugs in those holes as an easy check. the only thing that wasn't new were the wires so after getting the weak light on those two cylinders I was really hopeful that it was the wires so I put new ones on and no change. still the same weak light on the tester. AND I had to replace my lower intake manifold gaskets about a year ago because it was leaking like crazy out of the back. It will be extremely frustrating if that's leaking again. It's still starts up instantly and the plugs that came out didn't have any buildup on them. Would a coolant pressure test be the best was to see if there might be an intake gasket leak in your opinion? I just don't even know what to do. I still owe money on this truck and can't seem to get any help from the AUTOMOTIVE TECHNICIANS that I work with and it's extremely stressful.
Parker Waite Yes I would do a coolant pressure test as my next step on this vehicle. Also coolant leak into the intake often shows up in the oil too- try that "sizzle test" if you saw my cylinder head gasket video series.,
Sir you are totally awesome thank you very much for a wonderfully logical intelligent and well made video. We have a 2000 Chevrolet Blazer let me just replace the timing chain on after all of the other stuff and then the engine seizes up what would you suggest we should look for?
Thanks John, this was my first video ever and still one of the best I think lol! As for your truck, not a lot of info there- does it run good til it seizes? How to you unseize it? Is it actually a mechanical seize or does it just stop running? If you need a huge ratchet to unseize the engine by turning crank, you may have a spun bearing but usually the engine won't budge at all. Otherwise, if the seizing fixes itself after a while, you are probably hydrolocked- might have blown head gasket or leaking fuel injector.
How would we check for hydrolock? The sieze is just past tdc compression on #1. I say this because we tested the compression on one by using the old hand crank method and also reinstalling the distributor using all of your tips and markers to do so. Like I said your videos are awesome. Any suggestions or insights on how we can determine if there's a hydra locker not in one of the lifters would be deeply appreciated. God bless and keep you and yours and all good things. In love sincere appreciation, John w. Ketchersid
John Ketchersid You need to remove the plugs on the engine when it is locked and then start it- if liquid spews from a spark plug hole then it was hydrolocked.
Hey Matt! Let Me start out by saying that I find your instructional videos on the Chevy 4.3l very informative. I have a quick question for you; I have a 1999 Chevy Blazer Performance variant called the Seeker. It has a Vortech supercharger with MSD ignition that runs 5psi. I had the vehicle in storage for about 5 years. When I retrieved the truck, I got it a tune up and serviced. Now, I have intermittent check engine light and security light with severe hesitations above 70mph. Any thoughts would be deeply appreciated. All The Best, Rob
Since you have this on a p0350 video I have to assume the CEL code is a misfire. Just following the basic steps shown in the video covers all possible causes of any misfire condition. It will be either compression, timing, spark, or fuel causing a misfire. Need to narrow down sytematically to the source and then work to the root cause from there
Look, I can't help all the people who miss the whole point of the video and that is the diagnosis. The majority of people criticizing about replacing one injector vs the spider wouldn't even be able to get to the diagnosis of which injector to change, so whatever- otherwise why watch? The argument "new parts can fail from the box" is ridiculous- anyone who takes this attitude with a timing belt and doesn't change ALL timing belt components is a fool even if they still "work fine". QED.
I stumbled across your comment, but it didn't get sent to us automatically. If you use the 'reply' option after a comment, it is automatically sent to the author(s) above, but if you just add another comment at the top of the list then only the author gets automatic notification.
Working on a bravada with the same issue, p0306. What would cause there to be no fuel pressure at all with key on but has 50psi when running? Also when I turn the key on I don't hear the fuel pump but when I turn the ignition off I hear it??
I have a 2015 chevy ss sedan, with the same exact issue "P0304". So I'm going to follow all of these steps, and try to see if I can find the issue, even though the two vehicles are different. Thanks for the insight of potential fixes for me!!
Thank you i just bought a 1996 chevy s 10 pick up I am a mech but I am trying to learn about the truck the old owner baught and put in a fuel pump a oem 1 I am learning a lot about that spider is it expensive good info thank you
I appreciate the video so much we are haveing the exact same issue on the exact same cyl hopefully after the new injector it will fire right up we’re getting everything elce just no juice in cyl 5 by juice I mean gas but we are getting plenty of spark
Some of these systems are serviceable now. They make individual injectors that pull out from the top of the injector plug where the electrical harness plugs into at the top. you can find them at A1 Auto or on ebay for about $80 TO $90 a piece .There only for the GM OEM popet nozzle type.
Agreed. I am not sure why it didnt do that or at least go into OL3 which is what normally would happen if you pull an injector connector. Great observation and it surprised me too. All it showed was the misfire codes.
I have the same truck and it seemed sluggish off the line. There are two things that Made a huge difference! In the throttle body, on the underside of butterfly, there is a air restrictor riveted to the butterfly opening! Take it off but block the holes off or it will idle at 2000 rpm. Also the air box opening has another air reducer! I took both out and my truck has instant horsepower off the line now. It even sounds like my old Rod chester carb on my 68 Camaro when you floor it and you hear those 4 barrales crack open. But also my distributor plastic gear is worn out causing the timing to retard which eats more gas, less power, and efficiency.
+Oscar G P0014 is more likely to be a timing other than VCT. If I run into a VVT'd car that would make a good video but you might also want to check the CPS and CKPS signals to verify if you have other timing issue. My other channel shows how to check these.
Ok I checked it like you had. By firing gas into little containers. Each one squirted has no problem. I’m waiting for my battery to charge to check compression. My 4.3 is misfiring on cylinder 3. Timing is good, spark is good and I’m about to ohm check the spider injector. I’m a little nervous about testing compression and think I might have a bad valve seat because there is oil on my spark plug in cylinder 3. What psi of compression should my test or read?
Cylinder 3 read no compression at all, cylinder 5 and 1 have 170 to 180. I seen a video to try blowing air from my compressor using the compression tester with the Schroeder valve removed to blow air through the spark plug hole and see if it’s leaking at the exhaust valve, intake valve or piston rings. I’m going to try this tomorrow.
well there you go. Done deal- no compression so at the very very minimum you need to pull the head. And worst though- engine rebuild. No way around it- you have a major engine repair ahead. I would do the leakdown and determine if you need a cylinder head or a rebuild.
The distributor caps are notorious for "cross-bridging" and causing misfires. I've seen this issue on many Vortec engines that I have worked on. I tend to stick with factory GM replacement parts when it comes to electrical issues, rather than Advance Auto, O'Reilly, Autozone, etc.
U had said in ur video about the plugs the wires the low pressure and such well my engine would shake and my light would come and go and flash to service the engine code p0303 misfire so I replaced the spider and no luck turns out today I replaced the third plug and wire and cleared the code and drove around for awhile stepped on it a few times and seems to be running shifting and down shifting smoother and easier so for now I think the problem is fixed
+jacaughron55 I have no idea what you are doing but if you think it's fixed then good for you. But I sure don't see any data or evidence of any sort to indicate either way.
I want to ask my english is weak the point of rotar should touch the mark which is 6 no its mean timming is right even you tdc the piston no 1 so it is ok or not plz tell me
Same problem done everything you did plus more and I still have the same problem even after replacing everything anyways, 01 s10 4.3L 155-160psi on all cylinders, replaced injectors twice new plugs, wires, cap and button even though they were all just replaced maybe 10k miles before, new distributor and cam sensor and coil plus ignitor and made sure the ports were clean on the lower intake still no change, so I replaced the ECU still no change, cylinder is dead at idle but very slowly revving it even a tiny amount and it clears but if it’s under any kind of load or idle then cylinder 5 is dead any suggestions from there?
well what data did you get that indicated the injectors were bad? what dat indicated the plugs and wires were bad? what data indicated the distributor was bad? What was the Signal, ground and reference readings you got that indicate the Cam sensor was bad? what was the bypass test method you used that indicated the coil was bad? What was the failed output signal from the ECU that indicated it was bad? It’s hard to imagine you did what i did and came up with data showing all those parts were bad.
My 98 chevy blazer gave me a lack of power and acceleration problem, I replaced the fuel pump, ignition coil plugs, and wire, and it really ran good after that, I got the misfire code and now think it's like your showing a bad injector.
60 lbs is for poppit system , that had mpfi , injectors on the end. The newer style after 2001 doesn't need the fuel pressure that the old spring loaded poppit system did.
@@SchrodingersBox from what I have seen a minimum of 55, avg 60 - running pressure is not specified, once you pressure the rail up by priming it should not lose more than 10 psi in 15 min or a failure in the spider or regulator is suspect
I have a Chevy 4.3 vortec. Spark comes and goes. What initially could make the spark to be intermittent? From the distributor to the plugs no spark. Coil new, module is fine. Both getting power, coil receiving signal from module. Both getting power but no spark. Next day battery was weak put the charger on it car started right up. Let it run turned it off. Tried to start it nothing. Checked the spark, none. Crankshaft sensor?
Lots of things ranging from bad ground to bad cam/crank sensor to loose wiring at the coil... I usually try wiggling wires to see if I can reproduce the fault.
I have a 1997 s10 blazer it only has one mark I put it on the mark it's ponting at the 6 I'm getting spark out of the coil but not out of the cap I think its the crank sensor what do you think
I am trying to remember the design on these models (I no longer do much car stuff due to me job) but it is reasonable the cam sensor would explain this. I would try a cam and crank sensor bypass test if I was diagnbosing this car. I have several videos showing this on my pay channel in detail but there is also one on this channel that assumes you know basic electrical and operation of hall effect designs.
I have a issue with a 1997 Silverado 5.7 and I found this vid. It was helpful but I still have the same problem. so I thought you may have some pointers for a what seems to be a growing problem. well here it is. the truck runs good but 10 to 20 sec after it goes into over drive the truck stumbles. then runs fine. the strange thing is this happens every time it goes into over drive but doesn't set a code. I put a GM crate 5.7 in it due to the 215k mil on this truck. that's when this problem started. I originally thought it was a slipping trans so I replaced the transmission and torque converter. Witch now that the transmission is no longer slipping it has magnified the problem. I don't know we're to go now. I have spoken with several other people who have the same problem. but no solutions.
That could have been the upgraded GM MPFI spider injector. GM made a retrofit kit for 96-02 models that had the SCFI spiders with the crappy poppet valves. The MPFI spider injectors actually are serviceable - you can swap out individual injectors from the main body.
What evidence showed all of those were faulty? What was the resistnce on the spider injector showing? What was the resistance on the wires and distributer?
(03 Chevy S10) What could cause a misfire (P0300) While only driving 60mph or faster? When drop below 60 and the service engine light stops blinking and turns off. I checked the timing spark plugs, getting fuel to the injectors and found nothing.
Often at high RPM a cracked spark plug causes this or some resistance in the secondary ignition. But you should see this as result of RPM instead of vehicle speed
Good job, the fuel pressure from part also struck me as off, I am surprised you are not throwing a lean condition code especially with LTFT being at 25% (from you part one scan results)
I have a 93 4.3 vortex will crank no start fuel pump replaced along with a new coil but its getting orange fire someone told me its the pick up module ...and I'll have to take distribiter out does the same timing apply to a 93
What was the data you got indicating the fuel pump was bad? And why was there also a new coil as well? That makes no sense. I would need to see the diagnostic pressures and voltages that were used to come to those determinations in order to help.
Yes I know-- what DATA do you have from doing everything I did? What was the fuel trim? What was the resistance across the injector? What was the static and loaded rail pressure? You said you did everything that I did so I just need to know what the data you got when you did it!
hello! i have 2001 chevy s10 4.3 did a compression ck all cyl are 180 psi! random misfire P0300 @ now cyl #5 but change from cyl #4 to #2 if clear old p0300 then moves difference cyl! i changed all plugs,wires cap & rotor many times!! fuel injectors & went to new style injectors moved out body down to head ! all 3 o2 sensors chg! chg the distributor too ! the truck runs great i don't feel anything the eng was brand new 4 years old gm crate eng ! i've been chasing this misfire ! o yeah put in new fuel pump last year it was weak!! help!!!!! tim
Ive got p0300 with p0306 , 96 astro van 4.3l pulled #6 plug dry but has spark. New distributor plugs wires. 6 is not getting fuel my next check is this
@@SchrodingersBox because the guy i got the van fron didn't do a tune up since 2014 and found #2 plug cracked so the only two codes besides p0300 and p0306 was p1345 which is the distributor. all replaced now # injector is not pumping fuel pulled plug and its dry dont even smell like fuel. im saying at this point the spider injector is bad. plug is sparking..
@@SchrodingersBox I lost a good friend more like a brother a few months ago and I actually ended up getting his truck and it’s super ruff I’ve just been trying to get it going well enough to get it back on the road but there’s been a missfire I couldn’t find everything checked out except I haven’t tested the fuel system yet it runs fine at idle and misfires pretty good starting around 2k rpm’s
Well shaky engine loss of power loss of mileage it also took a second to start before I replaced the spider but the p0303 misfire was the code that kept repeating I'm thinking it could be a bad spider that I just happen to get the only one other thing I haven't done is the fuel pump
loved the video,comedy , but , u didn't say the price of the insect ? I'm having the exact problem , sucks that it"s not individually fixable , very helpful , thank u 👍👍👍👍👍
Ill throw a curve into the mix. I have a 94 Jimmy with the same issue. It is an OBD1 vehicle. No CEL. I diagnosed the problem similar to this video. I ended up throwing parts at it because I could not find the problem. I changed plugs, wires, spider, and distributor. Did a compression check and all are 145PSI. fuel pressure is 60 PSI.
@MarkySandy- Yeah that's exactly why I really only work on OBD-II vehicles- my scan tool only works on OBDII and without having some sort of starting point, you end up throwing parts at it. I might try using a vacuum gauge as seeing if possible intake manifold leak could explain your symptoms. Compression test and fuel pressure will not check for vacuum leak.
@MrMarksandy what you want to do is get a paperclip and short the two pins farthest to the right in the top row of pins on your obd port. The engine light will do a series of short short short flashes separated by longer pauses. Example, Flash ------ Flash, Flash, Flash, Flash, Flash would be code 15 The first three codes you will see flash will be code 12, which is the cars way of telling you the ECM is operational. Any additional codes will appear in the order of newest to oldest. Pay primary attention to the oldest codes as they can be the main cause of several other newer codes. -- -- -- -- + + -- -- -- -- -- -- ^ if you imagine that being the obd port you normally plug a scan tool in to, take a paper clip and bridge the two pins that I show as plus signs.
when i am driving ... my truck will jerk like it sounds like to me its not getting fuel an now i cant get above 60mph an the check engine light flashes the whole time while in throttle
Great video. Used this to work on my son's 2001 S10 with the 4.3. It had a P0300 that I was chasing. I had the engine out to replace front timing chain cover, oil pan gasket, intake gasket, and rear main seal. Replaced all plugs, wires, cap and rotor, they needed to be done anyway, did not cure problem. Pulled the distributor, and the drive gear was done. Replace distributor, all is good. Your video on getting things lined up saved me huge amounts of time and aggravation. 2001 timing chain cover has two marks, one at about 1 o'clock the other at 4, with #1 at TDC, lines on harmonic balancer line up to both marks in cover. Again, awesome video, thanks for taking the time to save us DIY'ers lots of time.
Great diagnosis Matt! Love the in depth videos! And how you rule everything out 100 percent...the sign of a great mechanic
Justin, Considering the entire cost of the repair was under $400 I hardly think my customer got taken. Now, had YOU done the repair which would have been more than twice that, then he would have been taken, single injector replaced or not- plus my customer now has all new injectors so doesn't have to worry about this happening with the others which are of same age and exposed to same conditions like he would with your fix. But I still thank you- because it's guys like you who keep me thriving.
Brother, I can't thank you enough! I blew the intake gasket and replaced it.. Tried to cheep out and reuse everything...
Through lots of codes and now I've replaced plugs, wires, pressure regulator and distributor setup.
Got it all back together again and I throw p0300.
I'm going back in to look better at the spider. This will help!
Funny how happy we are when we find something that's broken!
mrpeables It's indeed fun to find what is actually broken, but it is only successful if you do it without replacing things that weren't broke. The thrill is in the diagnostic and knowing you were in control and owned it through the process. Glad you adapted to the correct way now.
Hey, your videos have been very timely for me. I have four Blazers and one S-10. One of the Blazers blew a manifold gasket and filled the crankcase with antifreeze. We have that fixed now and are putting it back together. One of the things I needed to do is reinstall the distributer. I came across your video on that, which led me to this one. Very informative! Your explanations are very clear and concise. Keep it up!
I've got a similar problem on my 1998 Oldsmobile Bravada. It will occasionally misfire under load and bring on the SES light. The last time it happened was when I turned the A/C on while driving down the road. These videos will be very helpful to figuring this problem out. Thanks so much for posting them.
Matt you are an absolute winner of a mechanic and instructor! Thanks for your videos always so very precise and to the point! Awesome you are!
Again, just bumped into your channel while troubleshooting, and again gave up on throwing my pick up into the bottom of a river! Thanks!
Welcome back!
Awesome videos on this. I love how meticulous you are, and how you methodically go through a diagnoses. Got a $500 03 s10 4.3l in beautiful condition with only a couple minor problems. Fixed everything so far for 250 bucks, now trying to figure out the intermittent rough idle.. Drove it 600 miles so far, the CEL flashed for about 5 sec while at 70mph. I quickly slowed down and it went off and stayed off. Hasn't come back on since. Pulled the code, p0301, #1 cylinder. Pending code.. Going to finish doing all these tests and narrow down the issue. Thanks again.
You're a godsend, a decade later and this is the only reliable resource I can find for this problem. Only difference being mine just dumps fuel into cylinder 3 but I imagine I'm gonna be pulling that goofy spider out of there soon.
if it’s dumping fuel into the cylinder you will want to make sure the transistor is not fried and permanently grounded. check for a short on injector 3 first- if it’s shorted you definitely have high risk for blown transistor.
Ah. I've just listened to your brilliant explanation. So all this time i could have had the 2 lines lined up but that could have been exhaust stroke... better than any mercruiser titled videos. Bless you
Goof presentation and a nice piece of experience plus logic.
I am now Just driving my first non carburetor vehicle. This is for me a good look at the similarities and the new chunks.
Cylinder #6 was going into hydrolock due to the injector being stuck open with a piece of spider o ring. Popped the plug disconnected the coil and added nylon plug in coil for added safety disconnected injector power. Spun engine with starter and out came the fuel. Tomorrow we will have the new spider and all should be well.
Thank you again for cogent, logical, coherent and useful content.
Another favorite of mine is Wranglerstar channel. You will no doubt enjoy his work as well. Seeing him rebuilt an old one horse IH was good fun.
Jk
Excellent John. Not to scare you but you will want to be sure that you still "pulse" at the injector wires for that #6. If an injector shorts out, the transistor in the PCM is basically sending 12V right to ground with no load or resistance. It can definitely fry the transistor- basically a new PCM. If you put a new spider in and #6 Still is always stuck open, then you will very much need to verify if the PCM has been shorted. Conversely, if you do find the PCM has shorted, never install another PCM until you are sure you alleviated the short. Was it really a shorted injector or is the ground wire shorted to the frame instead of being controlled by the PCM? Catch my drift?
No short. Mechanical obstruction.
I bought a 97 astro van that had this issue but it had the original poppet at the cylinder set up. turned out when the previous owner replaced the fuel pump they refilled the tank with several cans of fuel. one which was full of leaves. I ended up replacing the pump and flushing the lines . disassembling all the injectors and disassembling all the feed lines and poppets. 3 and 5 had nearly 125 pounds of air pressue on them when they finally came loose. I soaked everything in acetone got all components clean and have had no issues with it for around 8 years now. about every 8 tanks full of gas I will throw a cup opf marver mystery oil in the tank and it seems to be keeping it all working well.
good vid.
@Spelunker and 12VGS- You guys are too kind! Thanks for the feedback. Actually, 12VGS, I'm a scientist (molecular biologist actually) but really, troubleshooting any problem uses the Exact same scientific method as curing cancer does. It's all a matter of proving one single cause is responsible for an observed effect and countering all other possible explanations that would refute your position.
Thanks for the great instructive videos. I have recently replaced the intake manifold gaskets on my 1999 GMC Jimmy 4.3 Vortec with 178000 miles on it. History of the process is I snapped a manifold bolt on re-assembly as my torque wrench was not clicking so i kept wrenching until I snapped the bolt. Well I had to disassemble the manifold and was able to cut a slot in the top of the bolt that was sheared off with a dremel and some fine diamond bits, I could then walk out the broken bolt with a flat bladed screwdriver. That made my day a lot brighter. I then went out and bought a new set off manifold bolts as recommended by my Haynes manual and other sources. The first assembly I just used the original bolts after chasing the threads with a die and cleaning out the bolt holes in the lower manifold with a tap as also recommended. Getting bored yet? On the 2nd reassembly I did not use a torque wrench as I was afraid I would repeat the bolt shearing so I just snugged the bolts in sequence til they were a nice pull. Specs for final torque is 11 ft. pounds which I thought was light but that is what the specs are. Any way I got it all together and it ran good for a day or so then I started getting a skip and a DTC code po3o6. Flashing ses light and the whole bit. I noticed that if i let it cool down for 8 hrs or so it would run fine for about 10 or 15 minutes and then it would start to skip and throw the same DTC code, but after a few days of that it now starts skipping as soon as i start it whether it is cool or warm, not intermittent anymore. As of this post I am still trying to find the problem. We have checked spark, changed plugs but not wires, replaced the distributor cap and rotor before the first reassembly, but took it off and inspected it as part of the diagnosis. The egr tube would not break free of the fitting when i took the manifold off so i thought i would cut the tube in a spot that i could re-assemble with some heating duct metal adhesive tape, which i did on re-assembly. However the night it started to run rough we inspected the engine and noticed that the tape had come off and the tube was opened up, so we fabricated a tube splice with some aluminum flashing and some small hose clamps, no change but after it cooled overnight it ran fine til it warmed up and the skipping/dtc code returned. i then coated the fitting tube and hose clamps with grey high temp RTV thinking I still had a vacuum leak there still no change. I have now purchased a new egr tube which i should be getting in a few days. Any thoughts on this would be appreciated. I am wondering about the spider injectors now after watching your video but i would probably look into the egr system first. Anyway i am a confirmed subscriber to your channel and will check you out as one of my first go to guys now. Thanks again and give me your thoughts.
When you said, "Getting bored yet?" I laughed and kept reading. :) Thanks.
I'm not sure how to help you except on one point. When you did one of your repairs I noticed that you said it still had the problem? After a repair always reset the computer. Sometimes, including EGR repair, once it's seen broken by the car, it'll keep compensating for it after the fix. Until you reset, you won't know your current situation.
It helps me learn even if I'm replying to an old post, so I hope you comment back!
DE Nichols Glad I made you laugh. Anyway it turned out to be the injector plug harness was not seating fully . I had to remove the plenum and scrape out the carbon from around the opening that the injector housing comes up through. It was not letting me seat the plenum down all the way. i cleaned everything up and lubed the gasket with some silicone grease and put it back on and she dropped in and seated down ,then I was able to plug in the harness and snap lock it in. I couldn't do that before and it was sporadic intermittent connection so that the injector was not always firing giving me the rough running and the flashing code. Since then all has been good knock on wood. ;-{)
Whenever I find one little connector undone that changes how the whole car is running I've exclaimed, "but I didn't even work on that part of the car!"
... hope I got a laugh back. :)
Oh memory is fickle. I changed my spark plugs so often that I had to get a tap and die set for the bolt that holds the spark plug coil in place. A little tip for you. I get maybe 60k miles on my iridium plugs and while I was only getting 12k on platinums.
Thank you so much for this instructional video. This helped me out a great deal.
I actually enjoyed viewing this. Please keep up the absolute best and very professional videos that you post for all of us mechanics. Again thanks for all the great information.
Thanks Adam!
Hey man! Thanks for this and your other informative videos. It's really helping me to diagnose similar problems on my vehicles. I ruled out spark on my Dodge Magnum 2.6L V6 (but changed the plugs anyways because of their age) for my misfire problem and (unfortunately) it was a fuel injector issue. Thanks again!
(PS I have a PhD in computational chemistry, so your systematic approach to diagnostics resonates with me)
Thanks for the methodical way of diagnosing the problem and pin pointing. My 1998 Chevy pickup I just bought had the same code pop up, P0305. My cheap scan tool had misfire number 5. So now I know what to look for.
I had been chasing this problem for a while never had a misfire before doing some maintenance on my truck. Installed a new spider on my 5.7L k1500. After a 1500 mile round trip I got a check engine light. When I put my scanner to read it said cylinder 5 misfire. Checked compression all was good installed new coil, wires, sparkplug and distributer and it continued to run like crap. Fuel pressure was good at 55psi. I never thought it would be the new spider I installed. I said the hell with it. It's a PITA but went ahead and removed the intake again and installed a new spider. It became a very expensive job since the old/new part didn't have warranty and walla engine sputtering went away and have not gotten a check engine light anymore. Horrible design makes me want to install a newer vortec 2001 and up just for the easiness of diagnosing and servicing of those engines.
Thanks for this man 😊. I bought a 96 s10 a couple years ago. High mileage, kind of a lemon. 😏
You know what they say, in for a penny, in for a pound lol. I've always run old carburetor vehicles, so this is the newest, and most problematical vehicle I've ever owned. That being said, these vids are gold 👍😁👍.
Wow! Thank you for taking the time to do what you just did.
#3 on my van . Spider ordered .
@90 TegTurbo- thanks for finally clarifying the injector replacement issue, your explanations sounds accurate and is probably why there was such disagreement on that.
You are also, technically, correct on the diagnosis being done "backwards" as far as the fuel pressure check however remember this video is basically a sequel to another video where indeed this test was done correctly as you indicated.
Thanks for the video, I am now more confident in my diagnosis. I have the same vehicle experiencing the same issue minus the low fuel pressure. I ran through the same checks prior to checking the fuel injection system. I am going to get under the hood this week to fix the problem.
Mark Jumper Since your fuel pressure is normal what is your diagnosis?
Sorry for the delay, I just realized you had replied.
I ran the code and received a P0305 misfire on the number five. Spark test was ok. Checked spark plugs and wires and they were all but shot. Some idiot who had the car before me put in the wrong spark plugs without even properly gapping them! Before I go on I should say I bought this 2001 Jimmy for $700, so any money I put into was fine by me. Anyways replaced the plugs and wires, distributor, and the fuel injector system. Once I was down to the fuel injector I decided to replace the head gaskets since I was having some leaks. Had the ICM tested and it was bad too. Still haven't got it all the way together yet as I have been driving my other car.
I also replaced every gasket from the heads up. This is my first DIY project on any vehicle so this has been a great learning experience for me.
Schrodingers Box
When my new distributor is fully seated it is 3 degrees off of the six mark. Is that enough to cause a crank but no start condition?
I have checked spark at all 6 plugs. Good.
I replaced the spider fuel injector. Fuel is getting to the injector.
Please help.
Mark Jumper
Mark Jumper
Thanks for making this video. Very helpful for my 99 Blazer misfire.
if you're referring to the fan tool it's a Lisle Fan Clutch remover tool- don't have the part# but you can buy it at any NAPA store.
If you're referring to the scantool it's Autotap which unfortunately has been discontinued.
thanks man u open my eyes on fuel problems
Very good information on troubleshooting and I learned something with the spider injectors. One thing to consider is the spark plugs. I have replaced two different spark plugs because there was no spark even though there was a spark going to the plug. Ohming showed that they were open.
An open spark plug was ruled out using the spark tester. I have never heard of an open in a spark plugA how would that even happen?? I have seen cracked plugs many times but an open seems impossible.
Hi , I really like your approach to problem solving. Your scientific background really shown up in here. It is refreshing to see logic being used in car repair. Your explanations of the underlying physics helped greatly in understanding the complex working relationship of the car design. The information you provided here and on the other video about long term / short term fuel trim were excellent.
I have a similar problem on a Subaru outback 2001 2.5 manual transmission and would like to get a few leads from you on where I should look as I am reaching dead end and don’t know what else to check.
Problem: CEL code P304 - Cylinder #4 misfiring detected - The misfire cannot be detected by sound or feel only reported as code. Engine runs smooth with good acceleration.
What I have done to isolate the problem:
Ignition
1. Replaced wires and spark plugs - No change on code
2. Swapped Coil Pack with one from a good vehicle - confirmed terminal 4 have good spark - No change on code
3. Replaced valve cover gasket, spark plug gasket - No change on code ( a Subaru mechanic pointedto some leaks at the spark plug gasket and said that it was the problem and want to charge $ 300 for the job)
Compression
4. Measured compression of cylinder 2 and 4 they both read ~155 PSI
Fuel
5. Swapped Injector 4 with 2 ( both injector actuated with low voltage applied on work bench) - No change in code
Electrical/ control
6. Replaced alternator - Battery voltage was 11.9 volts with engine at idle - Tested at auto zone indicated bad Alternator. No Change on code
7. Replaced ECM - No change on code (thinking that perhaps the driver of # 4 injection was faulty - i know swapping was bad but i was stuck with no new lead)
Air
8. Conducted smoke test and Starting Fluid test and found no vacuum leak
9. Measured Vacuum in the manifold and it reads 15 inHg (in the red lateing valve timing zone of the gage)
I need some of your logic to figure where to go next. Is there a correlation between low vacuum and Cylinder 4 misfiring? Vacuum Is common to all cylinder why would it cause only one cylinder misfiring?
For only cylinder 4 to misfire, the cause should be related to single branch of the circuit. So perhaps 1) fuel rail to Cylinder 4? (4 and 2 share the same fuel rail), or 2) Electrical connection to injector 4 ? is there any things else? Any lead would be greatly appreciated.
The one thing you overlooked is CONTROL to injector 4. Swapping the injectors would only test if you had a bad injector. You need to confirm there is voltage at the #4 harness when the computer commands firing of the injector. That's what I would do next. You can do it with a noid light or even a DVOM.
I have this exact problem. Getting code 4 cyl misfire but vehicle does not misfire. New fuel spider, new plugs, wires, distributor, distributor spine. Compression test ok.
One observation, if any other spark plug wire is pulled the misfire of 4 will stop??
2002 Chevy Astro van
Great video! Still driving my 1996 chevy blazer. 365,000 miles! Lol just replaced the fuel infection spider and many other parts. Only code left is misfire p0303 on cylinder 3. Having a very hard time figuring it out. This will help.
I recommend seeing my FASTTEC diagnostic video- a single single cylinder misfire only has 3 possible variables and that video covers them.
awesome video....very detailed and straight to the point...a master mechanic you are for sure..made me a subscriber...thanks for the help and now Im gonna follow your steps to repair my chevy s10..
Thanks for the video, Very helpful. Just wanted to ask how you would check the original spyder injection system that does not have the wires going to injectors. With continuity check as you did for a short in it?
Exactly.
I took out the crank sensor and it looks worn. Its scratched and i can feel an invention in it. The mileage on the vehicle is almost 200,000. If the crank sensor is no good, could it cause an intermittent spark or no spark at all? Previous owners also just changed the timing chain.
thank you so much for this video. my mechanic has changed everything electrical out from plugs to wire to the distributor. nothing checked in the fuel system and i started wondering about that. i have an '02 Chevy S10 with the 4.3 Vortec and im getting a P0306 code and have been getting it over and over, starting to get really frustrating but im sure now its a fuel thing. thanks!
Very well explained video I just installed new engine and new spider injection in my 98 Chevy truck I've been having random misfire motor has 1000 miles on it. I've replaced every sensor there is re checked my timing and firing all is dead on my next step is to do as u have done on spider injection although it is new still leaning towards this may be a defective part. Thanks for the video
Yeah, I'm working through the set, I like the way he thinks things through.
Ha, thanks Eric (great screen name btw!). I don't mind constructive criticism but when it's from people who either never turned a wrench or are professional "parts changers" challenged by a DIY, i guess I tend to get a bit fueled up. But these videos are for people like you, not them so maybe I shouldn't even pay them any mind. Thanks for your support!
the spock of the automotive world...."Logic will prevail"
Its Always sunny. We created the pickle party where we put our feelings aside when we make our decisions. Reason will prevail!
Could you explain the test that you did on the spider injector? There was continuity, and you said that it is shorted.
Did I say shorted? My apologies- it would have been an open if I remember. man this is an old video- I think its my first one lol.
Your test on the spider pack to test all 6 poppets at once... Can this be done without removing the intake? Or does the whole spider sit below/inside the intake?
Thanks for the advice. I did confirmed the connection of Fuel Injector 4 by connect an oscilloscope between one terminal of the injector and ground as well as using a DVM. DVM read 14 volts DC. Scope shown pulse width which increase frequency with increased RPM. I also used a stethoscope to listen for the ticking sound of the injectors. It sound the same as those in injector 2 and 1. do you know where I should look next? I just ordered an PC based reader that have trace capture. It will come non Friday and I hope to monitor it to see when misfiring happens. could you advice on which sensors or parameter to monitor. Many thanks
Thank you for a very informative video. You are very easy to follow.
That pressure did seem low .
Great example and logical explanation.
The injector assembly you removed is in fact the updated version. You CAN now purchase single injectors from NAPA and other part stores. But the fuel pressure issue also definitely needed to be addressed. This is the unfortunate case where the car needs two separate repairs. Can be hard to explain to the customer.
I was commenting about something similar on part I. I had a buddies car which diagnostically had 5 bad components. You hope as you go as you replace the other bad parts that the issue will be resolved, but sometimes you just know you're going to have to have the friend/customer except one loss at a time before its "all better". I took him through what was wrong one at a time so he's a satisfied friend, but it was a lot to swallow and months of him making more money to fix the next thing.
I'm just grateful he didn't lose another motor mount while solving the issues that broke it. Phew!
HEY YA MATT THANKS FOR THE TIPS I HAVE BEEN HAVE THIS PROBLEM WITH MY 2003 CHEVY SILVERADO 4.3 L VORTEC MIS FIREING AND CHANGE OUT EVERYTHING GOT GOOD COMPRESSION BUT HAVE TO CHECK FUEL SURE ITS THE FUEL FROM WHAT YOU HAVE DONE I HAVE DONE SO IM IN TO IN SIDE
Looks to me like it's probably a stuck caps lock key
no have done everything and its the fuel spider just like you said matt and ordered it be here monday and installed thanks for all the pointers and yes alot of know alls but your the man and your info to the letter matt again thanks so much for your help again my system fuel pressure was 32.lb
Ken Blais How do you know it was spider injectors if fuel pressure was 32 lbs??? What was the data you got that confirmed the spider caused that?
I have a spark tester just like the one you use in part 1 of this video. I've got a constant miss on #2 and #4 (On 5.7L Vortec). Does the intensity of the light matter? Number 4 was very dim but consistently lit. Number 2 was brighter at times and showed less misfires on the counter on my scan tool than number 4. compared to #1 which was brighter consistently.
Thought for sure I had a spark probably and replaced the only non new parts and put new wires on and there was no change.
What about a intake water jacket leak into the intake? That would probably show up on the plug though.
Going to the store to see if I can get a fuel pressure tester and at least check that.
Parker Waite Great question Parker- one of those that makes me wish I brought it up in the video. Yes the intensity of the light is proportional to the output of the coil-- er, I should say the output to the tester (the coil need not be at fault- high resistance in the wire could cause it too). In the event of suspecting a weak spark I will verify with another tester you have seen where can create an adjustable gap in the tester and measure the spark distance. Not sure if water in the intake causeing wet plugs would affect this- to verify it would be simple though- connect your light tester directly to ground instead of the plug. if it is brighter, then you have some evidence to support that, particularly if you swap the plug with another known good one (or dry it off).
Well i mean as a general possibility to causing a miss. So if i just put a test lead to ground instead of to the plug it may be more accurate of a reading? If i do have weak spark at ONLY 2 and 4 then that means wires, or cap and rotor. (Which are all new within the last couple months) A faulty coil wouldn't produce good spark on 6 cylinders and bad spark on 2.
Ah I wasn't aware of your model of car- I was thinking it may be a COP but even so it is possible a wire with high resistance could be responsible for weak spark on just one plug even with a distributor system. Anyway, Parker- answer to your question- not only is water leak into the cylinder a possible cause for misfire- it is actually the probable cause for it.
Schrodingers Box Well the frustrating part is the fact that it's got a new distributor assembly as of a couple months ago and i put new plugs in those holes as an easy check. the only thing that wasn't new were the wires so after getting the weak light on those two cylinders I was really hopeful that it was the wires so I put new ones on and no change. still the same weak light on the tester. AND I had to replace my lower intake manifold gaskets about a year ago because it was leaking like crazy out of the back. It will be extremely frustrating if that's leaking again. It's still starts up instantly and the plugs that came out didn't have any buildup on them. Would a coolant pressure test be the best was to see if there might be an intake gasket leak in your opinion? I just don't even know what to do. I still owe money on this truck and can't seem to get any help from the AUTOMOTIVE TECHNICIANS that I work with and it's extremely stressful.
Parker Waite Yes I would do a coolant pressure test as my next step on this vehicle. Also coolant leak into the intake often shows up in the oil too- try that "sizzle test" if you saw my cylinder head gasket video series.,
Sir you are totally awesome thank you very much for a wonderfully logical intelligent and well made video. We have a 2000 Chevrolet Blazer let me just replace the timing chain on after all of the other stuff and then the engine seizes up what would you suggest we should look for?
Thanks John, this was my first video ever and still one of the best I think lol! As for your truck, not a lot of info there- does it run good til it seizes? How to you unseize it? Is it actually a mechanical seize or does it just stop running? If you need a huge ratchet to unseize the engine by turning crank, you may have a spun bearing but usually the engine won't budge at all. Otherwise, if the seizing fixes itself after a while, you are probably hydrolocked- might have blown head gasket or leaking fuel injector.
How would we check for hydrolock? The sieze is just past tdc compression on #1. I say this because we tested the compression on one by using the old hand crank method and also reinstalling the distributor using all of your tips and markers to do so. Like I said your videos are awesome. Any suggestions or insights on how we can determine if there's a hydra locker not in one of the lifters would be deeply appreciated. God bless and keep you and yours and all good things.
In love sincere appreciation,
John w. Ketchersid
John Ketchersid You need to remove the plugs on the engine when it is locked and then start it- if liquid spews from a spark plug hole then it was hydrolocked.
Hey Matt! Let Me start out by saying that I find your instructional videos on the Chevy 4.3l very informative. I have a quick question for you; I have a 1999 Chevy Blazer Performance variant called the Seeker. It has a Vortech supercharger with MSD ignition that runs 5psi. I had the vehicle in storage for about 5 years. When I retrieved the truck, I got it a tune up and serviced. Now, I have intermittent check engine light and security light with severe hesitations above 70mph. Any thoughts would be deeply appreciated. All The Best, Rob
Since you have this on a p0350 video I have to assume the CEL code is a misfire. Just following the basic steps shown in the video covers all possible causes of any misfire condition. It will be either compression, timing, spark, or fuel causing a misfire. Need to narrow down sytematically to the source and then work to the root cause from there
Great info. ! I needed your tech on installing my dist. I was not sure on which mark on the crank to use for correct dist. install.
Yes you can replace one injection ,I did ,had a miss on #5 cid....good compress.....run like Champ now .....
Not on the 4.3 it has spider injection
What tool are you using? I can't find it online.
Look, I can't help all the people who miss the whole point of the video and that is the diagnosis. The majority of people criticizing about replacing one injector vs the spider wouldn't even be able to get to the diagnosis of which injector to change, so whatever- otherwise why watch? The argument "new parts can fail from the box" is ridiculous- anyone who takes this attitude with a timing belt and doesn't change ALL timing belt components is a fool even if they still "work fine". QED.
I stumbled across your comment, but it didn't get sent to us automatically. If you use the 'reply' option after a comment, it is automatically sent to the author(s) above, but if you just add another comment at the top of the list then only the author gets automatic notification.
It's good to see haters proving out and fueling your passion.
Working on a bravada with the same issue, p0306. What would cause there to be no fuel pressure at all with key on but has 50psi when running? Also when I turn the key on I don't hear the fuel pump but when I turn the ignition off I hear it??
Not all cars have a KOEO prime
That spider system is creepy as hell.
+Conrad Williams it is off the motor
I have a 2015 chevy ss sedan, with the same exact issue "P0304".
So I'm going to follow all of these steps, and try to see if I can find the issue, even though the two vehicles are different. Thanks for the insight of potential fixes for me!!
Think that pressure should be around 60-66 psi.
Thank you i just bought a 1996 chevy s 10 pick up I am a mech but I am trying to learn about the truck the old owner baught and put in a fuel pump a oem 1 I am learning a lot about that spider is it expensive good info thank you
I appreciate the video so much we are haveing the exact same issue on the exact same cyl hopefully after the new injector it will fire right up we’re getting everything elce just no juice in cyl 5 by juice I mean gas but we are getting plenty of spark
Some of these systems are serviceable now. They make individual injectors that pull out from the top of the injector plug where the electrical harness plugs into at the top. you can find them at A1 Auto or on ebay for about $80 TO $90 a piece .There only for the GM OEM popet nozzle type.
Seems like this car would trigger an injector circuit code. If so that would have given direction in the diagnosis.
Agreed. I am not sure why it didnt do that or at least go into OL3 which is what normally would happen if you pull an injector connector. Great observation and it surprised me too. All it showed was the misfire codes.
I have the same truck and it seemed sluggish off the line. There are two things that Made a huge difference! In the throttle body, on the underside of butterfly, there is a air restrictor riveted to the butterfly opening! Take it off but block the holes off or it will idle at 2000 rpm. Also the air box opening has another air reducer! I took both out and my truck has instant horsepower off the line now. It even sounds like my old Rod chester carb on my 68 Camaro when you floor it and you hear those 4 barrales crack open. But also my distributor plastic gear is worn out causing the timing to retard which eats more gas, less power, and efficiency.
thanks, because of you subscribing to Matt's channel, I found him!
Thanks for all your help
Hello Mat, could you do a video on how vct solenoids work. I got a p0014 causing a misfire.
+Oscar G P0014 is more likely to be a timing other than VCT. If I run into a VVT'd car that would make a good video but you might also want to check the CPS and CKPS signals to verify if you have other timing issue. My other channel shows how to check these.
Is there a way to test the stock spider injector as I did with the aftermarket one using an ohm test?
Yes you can test it easily right at the main connector. All the inputs and grounds are right there for the whole spider.
Ok I checked it like you had. By firing gas into little containers. Each one squirted has no problem. I’m waiting for my battery to charge to check compression. My 4.3 is misfiring on cylinder 3. Timing is good, spark is good and I’m about to ohm check the spider injector. I’m a little nervous about testing compression and think I might have a bad valve seat because there is oil on my spark plug in cylinder 3. What psi of compression should my test or read?
You should have about 150PSI. Compare it to other cylinders to see if it’s 20% lower.
Cylinder 3 read no compression at all, cylinder 5 and 1 have 170 to 180. I seen a video to try blowing air from my compressor using the compression tester with the Schroeder valve removed to blow air through the spark plug hole and see if it’s leaking at the exhaust valve, intake valve or piston rings. I’m going to try this tomorrow.
well there you go. Done deal- no compression so at the very very minimum you need to pull the head. And worst though- engine rebuild. No way around it- you have a major engine repair ahead.
I would do the leakdown and determine if you need a cylinder head or a rebuild.
The distributor caps are notorious for "cross-bridging" and causing misfires. I've seen this issue on many Vortec engines that I have worked on. I tend to stick with factory GM replacement parts when it comes to electrical issues, rather than Advance Auto, O'Reilly, Autozone, etc.
How do you diagnose it? Was there evidence of that here?
U had said in ur video about the plugs the wires the low pressure and such well my engine would shake and my light would come and go and flash to service the engine code p0303 misfire so I replaced the spider and no luck turns out today I replaced the third plug and wire and cleared the code and drove around for awhile stepped on it a few times and seems to be running shifting and down shifting smoother and easier so for now I think the problem is fixed
+jacaughron55 I have no idea what you are doing but if you think it's fixed then good for you. But I sure don't see any data or evidence of any sort to indicate either way.
Those spider systems are unfortunately pretty expensive too ($350+).
I want to ask my english is weak the point of rotar should touch the mark which is 6 no its mean timming is right even you tdc the piston no 1 so it is ok or not plz tell me
Soory I dont understand the question but the way you describe it, it sounds like the timing is off 180 degrees
@@SchrodingersBox sorry my enlish is weak God bless you
Same problem done everything you did plus more and I still have the same problem even after replacing everything anyways, 01 s10 4.3L 155-160psi on all cylinders, replaced injectors twice new plugs, wires, cap and button even though they were all just replaced maybe 10k miles before, new distributor and cam sensor and coil plus ignitor and made sure the ports were clean on the lower intake still no change, so I replaced the ECU still no change, cylinder is dead at idle but very slowly revving it even a tiny amount and it clears but if it’s under any kind of load or idle then cylinder 5 is dead any suggestions from there?
well what data did you get that indicated the injectors were bad? what dat indicated the plugs and wires were bad? what data indicated the distributor was bad? What was the Signal, ground and reference readings you got that indicate the Cam sensor was bad? what was the bypass test method you used that indicated the coil was bad? What was the failed output signal from the ECU that indicated it was bad?
It’s hard to imagine you did what i did and came up with data showing all those parts were bad.
My 98 chevy blazer gave me a lack of power and acceleration problem, I replaced the fuel pump, ignition coil plugs, and wire, and it really ran good after that, I got the misfire code and now think it's like your showing a bad injector.
what data do you have?
Excellent video.
60 lbs is for poppit system , that had mpfi , injectors on the end. The newer style after 2001 doesn't need the fuel pressure that the old spring loaded poppit system did.
What fuel pressure is normal on this system?
@@SchrodingersBox from what I have seen a minimum of 55, avg 60 - running pressure is not specified, once you pressure the rail up by priming it should not lose more than 10 psi in 15 min or a failure in the spider or regulator is suspect
have you made video if it has been messed with like you said a proper video
also mine is Chevy pickup 4.3 2001
I have a Chevy 4.3 vortec. Spark comes and goes. What initially could make the spark to be intermittent? From the distributor to the plugs no spark. Coil new, module is fine. Both getting power, coil receiving signal from module. Both getting power but no spark. Next day battery was weak put the charger on it car started right up. Let it run turned it off. Tried to start it nothing. Checked the spark, none. Crankshaft sensor?
Lots of things ranging from bad ground to bad cam/crank sensor to loose wiring at the coil... I usually try wiggling wires to see if I can reproduce the fault.
I have a 1997 s10 blazer it only has one mark I put it on the mark it's ponting at the 6 I'm getting spark out of the coil but not out of the cap I think its the crank sensor what do you think
I am trying to remember the design on these models (I no longer do much car stuff due to me job) but it is reasonable the cam sensor would explain this.
I would try a cam and crank sensor bypass test if I was diagnbosing this car. I have several videos showing this on my pay channel in detail but there is also one on this channel that assumes you know basic electrical and operation of hall effect designs.
distributor cap. ive seen it before.
I have a issue with a 1997 Silverado 5.7 and I found this vid. It was helpful but I still have the same problem. so I thought you may have some pointers for a what seems to be a growing problem. well here it is.
the truck runs good but 10 to 20 sec after it goes into over drive the truck stumbles. then runs fine. the strange thing is this happens every time it goes into over drive but doesn't set a code.
I put a GM crate 5.7 in it due to the 215k mil on this truck. that's when this problem started. I originally thought it was a slipping trans so I replaced the transmission and torque converter. Witch now that the transmission is no longer slipping it has magnified the problem.
I don't know we're to go now. I have spoken with several other people who have the same problem. but no solutions.
+James McDonald What data do you have? Can't help without data
That could have been the upgraded GM MPFI spider injector. GM made a retrofit kit for 96-02 models that had the SCFI spiders with the crappy poppet valves. The MPFI spider injectors actually are serviceable - you can swap out individual injectors from the main body.
Did all the spark plugs, wireset, distributor cap, distributor rotor button and new spider injector AND STILL MISFIRING! Any ideas??
What evidence showed all of those were faulty? What was the resistnce on the spider injector showing? What was the resistance on the wires and distributer?
(03 Chevy S10) What could cause a misfire (P0300) While only driving 60mph or faster? When drop below 60 and the service engine light stops blinking and turns off. I checked the timing spark plugs, getting fuel to the injectors and found nothing.
Often at high RPM a cracked spark plug causes this or some resistance in the secondary ignition. But you should see this as result of RPM instead of vehicle speed
This is a terrific video, thanks.
Good job, the fuel pressure from part also struck me as off, I am surprised you are not throwing a lean condition code especially with LTFT being at 25% (from you part one scan results)
I've seen that in a few videos on GMC products. You see an obvious condition on your scan tool on LTFT and the code didn't come with it.
Great simply explained vid! Thanks dude.
Glad you liked it!
Can you adjust the timing with a timing light?
no, you can validate timing with a timing light. These models are not mechanically adjustable.
I have a 93 4.3 vortex will crank no start fuel pump replaced along with a new coil but its getting orange fire someone told me its the pick up module ...and I'll have to take distribiter out does the same timing apply to a 93
What was the data you got indicating the fuel pump was bad? And why was there also a new coil as well? That makes no sense. I would need to see the diagnostic pressures and voltages that were used to come to those determinations in order to help.
Wouldn't low fuel pressure cause a misfire?
It could.
What if I did everything you did, including a new spider injector, and I still have a misfire?
Suggestions?
Why did you change the spider injector? what was the data you got that showed it was faulty? i would start there.
Schrodingers Box I have a misfire in cylinder 5
Yes I know-- what DATA do you have from doing everything I did? What was the fuel trim? What was the resistance across the injector? What was the static and loaded rail pressure?
You said you did everything that I did so I just need to know what the data you got when you did it!
hello! i have 2001 chevy s10 4.3 did a compression ck all cyl are 180 psi! random misfire P0300 @ now cyl #5 but change from cyl #4 to #2 if clear old p0300 then moves difference cyl! i changed all plugs,wires cap & rotor many times!! fuel injectors & went to new style injectors moved out body down to head ! all 3 o2 sensors chg! chg the distributor too ! the truck runs great i don't feel anything the eng was brand new 4 years old gm crate eng ! i've been chasing this misfire ! o yeah put in new fuel pump last year it was weak!! help!!!!! tim
What if the spider has been replaced and still reads the p0303 code?
+jacaughron55 Uhhhhhhh... thennnnnn... the spider wasn't the problem. What data did you have that indicated spider was the problem?
Ive got p0300 with p0306 , 96 astro van 4.3l pulled #6 plug dry but has spark. New distributor plugs wires. 6 is not getting fuel my next check is this
so wait- why are there new plugs and wires and distributer when you have a misfire on #6 with spark?? what am I missing there?
@@SchrodingersBox because the guy i got the van fron didn't do a tune up since 2014 and found #2 plug cracked so the only two codes besides p0300 and p0306 was p1345 which is the distributor. all replaced now # injector is not pumping fuel pulled plug and its dry dont even smell like fuel. im saying at this point the spider injector is bad. plug is sparking..
where are you located ? youre great
Denver Colorado
This video really saved me
glad to hear it.
@@SchrodingersBox I lost a good friend more like a brother a few months ago and I actually ended up getting his truck and it’s super ruff I’ve just been trying to get it going well enough to get it back on the road but there’s been a missfire I couldn’t find everything checked out except I haven’t tested the fuel system yet it runs fine at idle and misfires pretty good starting around 2k rpm’s
Well shaky engine loss of power loss of mileage it also took a second to start before I replaced the spider but the p0303 misfire was the code that kept repeating I'm thinking it could be a bad spider that I just happen to get the only one other thing I haven't done is the fuel pump
loved the video,comedy , but , u didn't say the price of the insect ?
I'm having the exact problem ,
sucks that it"s not individually fixable , very helpful , thank u 👍👍👍👍👍
Ill throw a curve into the mix. I have a 94 Jimmy with the same issue. It is an OBD1 vehicle. No CEL. I diagnosed the problem similar to this video. I ended up throwing parts at it because I could not find the problem. I changed plugs, wires, spider, and distributor. Did a compression check and all are 145PSI. fuel pressure is 60 PSI.
@MarkySandy- Yeah that's exactly why I really only work on OBD-II vehicles- my scan tool only works on OBDII and without having some sort of starting point, you end up throwing parts at it. I might try using a vacuum gauge as seeing if possible intake manifold leak could explain your symptoms. Compression test and fuel pressure will not check for vacuum leak.
@MrMarksandy what you want to do is get a paperclip and short the two pins farthest to the right in the top row of pins on your obd port. The engine light will do a series of short short short flashes separated by longer pauses.
Example, Flash ------ Flash, Flash, Flash, Flash, Flash would be code 15
The first three codes you will see flash will be code 12, which is the cars way of telling you the ECM is operational.
Any additional codes will appear in the order of newest to oldest. Pay primary attention to the oldest codes as they can be the main cause of several other newer codes.
-- -- -- -- + +
-- -- -- -- -- --
^ if you imagine that being the obd port you normally plug a scan tool in to, take a paper clip and bridge the two pins that I show as plus signs.
Derrick Hodges As I stated earlier. There is no CEL.
You can still have "pending" codes that don't trip the cel. It's worth checking out just incase.
Derrick Hodges
I checked the codes with a scan tool. No codes. Good idea tho...
when i am driving ... my truck will jerk like it sounds like to me its not getting fuel an now i cant get above 60mph an the check engine light flashes the whole time while in throttle
ok and what where the results of the diagnostics tests you did as shown in the video to isolate the problem?