Chevy misfire 2
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- เผยแพร่เมื่อ 14 ต.ค. 2024
- 98 chevy pick up came in for a bad misfire. Customer had already changed the spark plugs and wires but still had a bad miss. We put the engine on the scope and saw that it had a secondary ignition problem. A common problem on this style distributor cap is when there is too much resistance for the spark to jump at the spark plug it looks for an easier path to ground.
Hey warren thanks for splaining how these caps fail - I knew they were problematic but never knew the root cause of failure - thanks !
Remember the goog old days when engines were simple and easy to fix , all quality parts no plastic crap , sometimes i dont think all this technology is worth it but i guess thats what the car companies want , get tired of chasing gremlins and buy new ..im chasing a bunch in my 99 denali , got to love the spider injectors under the intake , thats just frighten genius engineering right there , lets have to pull 50 things off to change injectors and make them crap from stock so when they take it to the dealer we can rape them to swap our new design in ...ive never met an car engineer but i think they should have to work on cars for 10 years before they are allowed to design cars , maybe then they would feel our pain ....
Took me 3 days to pull all of the accessories off the top to take care of intake gaskets and replace spider. Fun! 😃
This may help; I resolved a misfire issue that drove me crazy, I have a 96 Vortec 7.4, Issue: Misfire on #5, I changed the plug, cap and rotor, and even replaced the coil, still a misfire, I then used a new spark plug wire to spark test each number, no spark at all on #5, I finally pulled the distributor, held it horizontally and rotated the shaft, it was then that I noticed the problem, the rotor was warped, it almost bottomed out at the number #5 position, I removed the rotor and noticed the base plate was slightly bent or the shaft itself was bent, I replaced it with a MSD all Alloy distributor, cost; $65, and problem solved! I very rarely buy after market parts, I'm big on ACDelco, but their plastic distributors suck! this is my 4th distributor on a engine with 210K miles. If you cant find the misfire, this is something to check!
if you change out the original ac delco distributor . keep or use the original spiral dis. gear, it is hardened and matches your cam gear.
OMG THANK YOU TIMES A FREAKING MILLION!!!! 96 Chevrolet extended cab 5.7 L and I cannot find this damn misfire for anything. I have replaced the plugs many times cap rotor and wires three or four times and it's driving me batshit crazy. I brought up that the distributor had a problem with it and people are getting like I'm speaking ancient Egyptian. I'll guarantee you it's something like that. I thank you
Thanks, have any pics ?
@@jhanlon1903 I changed distributor, rotor sparks,wires mine still has a misfire on number 7 I'm fuckin puzzled on this one.
Changed,pluges,wires,distributor cap rotor ,oil change map sensor still misfiring cylinder #7 I'm so miserable trying to figure this out ,only thing I can think of know is the ignition control module is probably not reading it .any help if any has ever had this problem even checked the plug and it was good.
this was exactly my problem 26 buck and back in business
Thanks, the cap was only 2 years old, i was not shocked it was bad, but it presented as wires
Learned something new, thanks for explaining this so well, I think I'm having the same issue with my 97. 325K, past time to replace:)
I’m in the same boat with my 98 K 1500
You are the smartest person in the world! I got my old 97 GMC fixed thanks to this video!! For $35 dollars
Hi which cap brand did you buy?or what did you do
It was so long ago. But it was AC Delco? Hell idk
the tool I use to test with is "KD Tools 2632 Portable Ignition System" I don't know if they are still in production because that type of ignition system is pretty much obsolete. Not gone but no longer in production. I have seen them for sale though. both new old stock and used Just google the name. the tool is actually use to run a vehicle that has a bad ignition coil or when the points don't work and send spark. Will work on GM HEI if the ignition module is bad but the coil is still good.
can you ever feel the misfire or is it just a code that shows up in the computer?
Thank you for this video. This explains all my problems.
Always clean the VENT SCREENS in the bottom of the HEI distributor . Most have never been touched .
man thank you for this video my old but dint see any cracks so i over looked the cap as fine after seeing your video i went back and it fixed my problem!keep up the great videos
outstanding............. sometimes even when 'new' this happens, i hear
I always replace the cap rotor when doing plugs and wires
After watching this video, I tested my dist cap the same way using a 15,000 volt transformer out of a neon sign & found my problem.
Thanks, my Chevy Blazer had the exact same problem with the distributor cap.
Good information !
What year?
@@yalondaruckel9397 it's a 2001 Chevy Blazer, mine.
This video should be in top 3 when watching a video thank you sir for the video
Thanks for the info. Just solved my issue! runs like a top now.
i am thowing a p0300 code on my 99 suburban 5.7. replaced the plugs n wires but the problem persists. i am suspecting my cap is causing this. thank you for this diagnosis video!
Me too, was it this?
Had exactly the same problem on my Chevy Astro 94..... Thanks
this EXPLAINS everything!!! Thank You.
good demonstrate.I got a 98 van with 5.7 it seems to be out of timing, I check the timing it seems to be ok. next I'll change the cap. cool video thax
Just to save everyone some frustration and heartache. DO not use anything other than AC Delco parts on a chevy vortec unless you absolutely cannot afford to spend the extra money for AC Delco. I have bought more cheap stuff to replace things on my truck, and most of them are not up to par. so it leaves you with constant doubt as to if the problem is something else because you just "replaced that with a new one". It will drive you crazy. take my word..
Good info. Ive been chasing issues for 2 years now, and its always the same thing, thats why they give us warranties. Screw that though, who wants to keep changing out cheap parts
Facts!
Nice demonstration! These caps are absolutely terrible. I wish someone would make an old school type cap to fit this dizzy...
I was starting to think that it was just me, or that there was something seriously wrong with my truck.... I have gone through 5 caps in 4 years, 2 of which were within 4 months.
First time i've heard of this, thanks
Will this throw a P0303 code on a 5.7L Chevy Silverado? It’s a ‘97.
I replaced my spark plug. Still misfire when driving at high rpm. Rough acceleration. Now im gonna replace distributor cap , spark plug wire , sparkplug rotor and spark coil
Would this be the same on the 305 Vortec? I'm assuming the ignition system is probably the same
Msd makes a nice cap and rotor, built better than most.
What about AC/delco ?
How did you test the cap did you use spark from the coil wire and regular tester?
What power source did you use to test?
This cap design is junk and should have been redesigned back to the old style cap. I have to replace the cap on my 2000 Safari every six months due to corrosion and misfires
Awesome. Thanks Warren.
What spark generating device and probe are you using here?
Dam bro Thank You!! I had no idea and worked on my 7.4 misfire all day yesterday!! Found your video and boom 🤯 I had same issue with 3&7 carrying across each other!! Thanks again!!
Is it possible to see the burn area in the cap, or do you have to run high voltage thru it? It also looked like you had some bleed on other cylinders. I heard cheap caps may not hold up too long. Do you recommend only OEM or any type of brand or material? I have a 99 Yukon 5.7 1500 set-up. Thanks.
All the caps I have seen have no visible damage. They have all burned through internally. Yes, the tool I use to create the spark to test the cap does bleed through almost everywhere on the cap but what I look for is where the spark doesn't loose intensity. That's a burn through area. Even the OEMs can burn through. My suggestion on a cap replacement is get a cap that has a warranty and keep your receipt in the vehicle. This way you can get a replacement if it goes bad again.
@@WarrenAutomotive Internal burn-thru makes sense so does bleed-over. Sometimes actual cracks are hard to see. I went for a bit of an upgraded cap at a local store. I've done plugs, cap & rotor so far. Also ran Cataclean thru and CEL finally went out leaving no codes.
I've been trying to localize the cause of a misfire. A local repair shop "genius" without ever looking at car, said it was definitely the spider injector poppets. I guess he had an internal scope built into his brain- or so he thought... Last night I opened the hood and looked for arcing wires in the dark and found three areas which were pretty bad. You could hear the constant fast ticking pretty good too. You'd think that would cause an engine code. I had a repair shop do the intake gasket a couple years ago and apparently they just "slapped" the plug wires back in and left them laying on the valve covers along with cracking my distributor housing from tightening the cap too hard. Nice...
I ordered a set of 8mm Summit Racing wires today which have a 270 ohm rating.w/suppression and spiral core. Hope this will fix misfire.
Thanks for your reply!
@@freedomkeeper8003: One easy way to check for bad spark plug wire is to use a spray bottle with just water in the bottle and spray it on the spark plug wires while the engine is idling. The engine should not be affected by the spray. If the engine starts to stumble and miss then it is very likely that one or more wires have openings the the spark can jump and short out rather than go to the spark plugs.
Injectors can cause a miss. dirty injectors, bad poppets (if applicable) fuel pressure... these things won't be affected by spraying water. So if the engine has a misfire from those things spraying water should not make any change if the miss.
You should have the engine hooked up to a good scanner and have it scanned for misfires. See if the scanner has the misfire counter. This way you see what cylinders are missing and how much they are missing
@@WarrenAutomotive Really appreciate your reply. Initially did visual inspection of wires and they looked ok. I will try spray bottle today. Trying to avoid cost of scanner diagnostic. Got car three yrs ago from orig owner. Is probably due for tune up anyway. Cap & rotor had some deposits. Has 203K miles. If you guys were nearby I'd stop in.
Right in the middle of all this my front seal on rear diff failed pretty bad. I fixed that. What a piece of mush plus 2 rips and cord showing through.
Thanks again.
Are u using a battery charger with the test light??
B4 you do anything check for spark on all wires if there's no spark on one then that's your problem simple as that
is this issue prone to these style of distributor caps? would too much resistance also be caused from using too big of a gap on the spark plugs? or wrong wires? i think i am on my third distributor cap now, and i keep on coming back to the same miss issue. this time i have a clear cap, and i think i can see the arc inside now where it is occurring...would the best cap to go with to prevent this be the ac delco?
Had same issue did samething as customer . took cap off and it was all Corroded so I replaced it and rotator so far so good! I'm going to replace to 2 upstream o2 sensors and ignition coil for the hell of it . 05 silverado 1500 4.3l 200k.
good video have same issue 2001 4.3 Blazer but i notice on Oriellys store some caps terminals are made from Aluminum- copper and carbon..... which one is reccommended?
thnx it reads a misfiring when i hit speeds 60 and over.
we mite find the problem if we find out which terminals work better; Aluminum- copper and carbon terminals??
Go with copper if you can. Using dielectric grease on the terminals would help too
Gracias!!!
I have been through 4 distributor caps and rotors and recently had a $700 "fix" with new distributor and it burned up again in 4 weeks. It used to go about 4 to 6 months without going out. I have no idea what is burning up these distributor caps and I am broke for the most part. Please help!
that was f****** awesome
is that a normal test light? where is it getting electricity?
Thanks for sharing 👍
I am on my fourth cap and rotor in four weeks. Truck runs great for six days and boom, I get the misfire. I have new ac Delco plugs and wires. Do you have any idea what could be causing this to happen? In my research this seems to be a common problem for late 90s vortec engines.
are you sure the cap and rotor are the problem? When you change the cap and rotor can you see something wrong with them? If you are burning through the cap repeatedly I would try another brand or something. Unless you have a super hot coil there shouldn't be so much KV to burn the cap and rotor that often.
Thank you for the reply. When I take the cap and rotor off there is oxidation and at times there may be a black mark in the cap or rotor. My thought is the coil is sending too much voltage but I am not sure how to test for that. is a hot coil a common problem? I have tried several brands of cap and rotor with the same problem. what voltage should the coil be sending to the distributor?
Is the coil the stock coil or is it a hotter coil?
Things that can cause the spark to look for an alternate ground instead of the spark plug are large spark plug gap, high resistance in the spark plug wires or coil wire, corrosion on the contact posts of the coil or distributor cap. Could also be a weak coil that can cause problems that seem similar.
best way to see coil out put is on an ignition scope. It measures the KV spike it takes to start the spark to fire
WarrenAutomotive the coil was replaced about a year ago with a new coil. It is a Oreillys coil. It sounds like I need to take it into a shop to have them put a scope on it because I don’t have that. I’ll check the gap on my plugs too. I have AC Delco plugs and wires in it. Once I get it figured out I’ll let you know what it was. Thank you for taking time to get back with me.
dan carmony I'm having the same problem today with my 96 7.4 L Single spark plugs fixed it a year ago and now I am wondering if I need to spring for better (dual spark) or a new Distributor cap.
How are you getting electricity to the cap to test it?
I'm thinking neon transformer
I'm going to go with an ignition coil tester machine
How were u feeding spark to the cap
using the KD 2632 ignition tool
we had one of those coil test machines that sent out 40,000 volts to test ignition system in outboard marine shop.
I want to find one . Who makes them? I could use a 12v coil and points etc to make my own.
I made my own using a 15,000 volt neon sign transformer & it works perfectly.
I replaced my dist cap . It ran fine for a quick test drive , I restarted and it started skipping again.
the distributor cap burns through because it gets old and the material gets weaker and the spark wears through looking for an easier ground. One reason this happens is the spark plugs and wires build up more resistance. Heavy load on the engine, wires that have high resistance, spark plugs that have a high resistance like a latge gap from the plug being worn can contribute to a misfire.
@Michael Fresh: this cap has burned through internally. That makes the spark jump to a different spark plug. It can cause a misfire or it can stop the vehicle from starting all together.
Backfiring going down the road could be the cap. It could also be a lean misfire. Not enough fuel in the cylinder to fire correctly so when it is expelled into the exhaust it is ignited from another cylinders hot exhaust. Always verify your firing order. Backfiring on decell could be a bad egr valve or a leak in your exhaust.
@Michael Fresh: the damage to the cap is internal. You can't see it. that's why I use the spark tester to find it. You could just try a new cap and see if it cures your problem
@@WarrenAutomotive do you know anything about the spider injectors I've changed everything but those and the o2 sensor on my 99 s10 I'm currently waiting on the fuel pump
@@finitofee833 what are you trying to fix? What is the problem with your vehicle? Replacing parts doesn't tell me what it is that you are trying to get to.
Very helpful, thanks a lot!
I have a wrecked 1998 Chevy Silverado been misfiring even before the wreck trying to fix it up and this is the only problem I have left so I will try this
Update?
Warren I got a few questions sir?
okay, how can I help?
@@WarrenAutomotive so I got a 00 vortec 350 replace the distributor 2 months ago today I disconnected cylinder 3 spark plug wire n it turn on wen I put it back it shuts off n left me stranded n now won't turn on on cranks any advice?
Francisco, have you checked to see if you still have spark from the coil? Why did you pull the spark plug wire and turn the engine on? So, when you pulled the wire off the spark plug was the engine running? If that's what you did, did you have spark jumping from the spark plug wire while the engine was running? But now, the engine doesn't turn over when you put the key in the start position or does the engine crank over but it just won't start?
@@WarrenAutomotive have spark on coil I clean the distributor cap had corrosion but dint check for cracks or check if the rotor was burn or warn out n yes wen I put the cap back dint wanna start so decide to check for spark on cyl 3 took the wire off n it started that's why I left it like that.
@@franciscohuerta9860 okay, so it didn't start even before you pulled the wire off the spark plug. (red herring) If you have good spark from the coil then it's just the distribution to the cylinders. Rotor could be grounded or the cap could shorted inside. The cap and rotor are pretty easy to replace. If you don't have the equipment to test them replace them and see if it solves your problem
Changed my distributor,plugs,wires,rotor, oil change mao sensor even took spark plug out to see if anything even though it's new I'm puzzled on this I'm still have cylinder #7 misfire. I was reading up on this could be my ignition control module not reading my misfire. So this video really didn't help for my problem.
this video is for a very common problem on this particular style distributor cap. It can cause misfires or it can make it so the engine won't start at all.
okay, how do you know you have a misfire on #7? Do you have a p0307 code? I don't think your ignition module would the problem for a misfire for a particular cylinder. Things to check, if the spark is okay, injector, cylinder compression, cylinder leakdown, valve lift (check for worn cam) and other things.
I replaced the cap still didn’t fix the problem and then I replaced the wire and spark plug and it was the same . I clear the code and it come back right away it’s says permanent code ? Please help what next I ran out of solutions . 1997 Chevy express van 5.7 engine P0302 .
since the computer says it on one particular cylinder (no. 2) I would look at the injector or the compression of that cylinder. You could try switching the #2 injector with the #4 injector and see if the miss moves with the injector or stays on #2. If the miss follows the injector then the injector is bad. If the miss stays on cylinder #2 then I would look at something mechanical. (That's if the spark is all good like you stated.)
@@WarrenAutomotive wow I never thought about this , I will try it . Yes all sparks are good and I’m getting sparks from the end of the wires all of them . Worst case scenario if the injector not bad then it would be lifters or falling cylinder ?
@@WarrenAutomotive thanks a lot for your reply btw
@@EARTHKEENING could be lifters, worn cam lobe, low compression from rings, or could be a burned valve. But injector or injector driver are not uncommon
@@WarrenAutomotive I switched the wire plug from spark 2 I put it on 4 and I put wire 4 on spark 2 now I’m getting p0300 random miss fire help please
I have a 1999 GMC Seirra 1500 w/ 4.3 LV6 everytime it rains, it will not start, getting wet in cap have tried 4 new caps any suggestions please ?
Kathy Gilder you are in need of a crankshaft position sensor it’s under distributor cap and rotating cap a little trick to remove then just plug in a new one. It fixed my 97 Tahoe took me about 6 months to figure it out? Good luck.
My neighbor has this problem, does anyone make a fix for this bad design?
how did you put current to the cap or what did you do to get current to the wire in min. 2.25
spark is supplied from a KD portable ignition system bypass tool. It generates spark in place of a coil and ignition system so you can get the engine to run as long as the distributor is turning. It has a switch so you can bypass conventional and HEI ignition systems. On the HEI it will use the original coil though.
WarrenAutomotive i have read the comments and replays but I'm still confused how you stuck current to it
@@WarrenAutomotive would u give the KD p/n for this tool. could it be found @ the local auto parts stores. thanks for ur informative vids. i'am a longtime DIYER & would like to have this tool in my testing arsenal,hope this tool is not to $$$.
@@ghuey6983 the tool I use to test with is "KD Tools 2632 Portable Ignition System" I don't know if they are still in production because that type of ignition system is pretty much obsolete. Not gone but no longer in production. I have seen them for sale though. both new old stock and used Just google the name. the tool is actually use to run a vehicle that has a bad ignition coil or when the points don't work and send spark. Will work on GM HEI if the ignition module is bad but the coil is still good.
@@WarrenAutomotive THANKS VERY MUCH FOR UR QUICK RESPONSE.HAVE A GREAT WK.
I hope this helps someone. I spent hundreds on my 98 5.7L with a similar problem. I had replaced the distributor cap, coil, ignition cables, plugs, ignition module. Turns out, the cheap plastic the distributor cap is screwed to was cracked so the screws weren't holding. Sometimes it had power, sometimes a miss, then it would run fine for days perfectly. Grrr... p/n Dorman 90449 Distribution Repair Plate fixed my problem.
Johnny5 always use ac Delco parts
I got 5.7 changed plugs and wires distributor cam sensors etc still miss with little bit back fire when get on it with gas pedal it runs better but not right
These caps have always been a joke with leakage, should be a scheduled maintenance item.
So we have a 97 chevy that misfires when driving and it seems like it does not have full power until it accelerate on its own. We replaced spiders, wires, plugs and fuel pump and fuel filter but we still have a rough idle can anyone help ?
you should take your truck to a shop that has a scope so they can see what your firing KV looks like and can do a crank test for relative compression. Make sure your exhaust is good too. restricted exhaust will reduce power on full acceleration but be okay on cruise or low acceleration. If you could scan the OBD2 values you could look at your fuel trims and see what the computer is working with.
Would you get a p0300 code?
you could but most likely it would be more specific if this was on an obd2 vehicle
@@WarrenAutomotive more specific to what? Vacuum or electric?
@@leeamerican4257 more specific with OBD2. This cap was used by millions of vehicles that didn't have OBD2 so they don't show cylinder specific codes. On an OBD2 vehicle you might have a P0300 code but a scanner should be able to use the misfire counter and see what cylinder or cylinders are missing live. Older vehicles that can't get misfire data from the computer would use a Ignition scope and look at the firing voltages to see what cylinders show a problem.
I bought one of these caps.at a auto parts store.it was no good.went and bought a dealers cap.buy only.chevy caps
Yep
Tool name please 😔
KD Tools 2632 Portable Ignition System. I don't think it is made anymore. you can find used though. they are used to get standard and HEI ignitions running so you can drive them into the shop (and as a diagnostic tool) It replaces the points and coil in standard ignitions and the replace the ignition module for HEI
To.much moisture running onto the cap causing corrosion to build up best bet is to spray down the cap with wd40 to make water resistant will last 6 months
That makes sense. My truck is hardest to start when it’s raining.
I have found these distributors having a problem clogging the super tiny vents that are in tiny round wells on the bottom of the distributor body. They clog up very easily and when they do the cap holds moisture in it and probably vaporizes allot of it making a steamy atmosphere and an environment ripe for carbon tracking to develope. Some compressed air can blow the clog out of these tiny vents and that may save you from these caps cross firing from probable self established alternates (carbon tracking). These "vent holes are in the sides of these small wells and they are about the diameter of a sewing needle and clog very easily.
That's pretty wild I had a brand new one out of the box bad also
Most people never think of the MAF SENSOR. it is obvious first test to check for malfunctioning when you have bad timing, misfire, white smoke & running like crap in general....
The test is unplug it while idling - if motor keeps running MAF is broken - replace the MAF sensor assembly & car or truck will run great.
so what does the number 2 solenoid go to? shifter? starter? transmission? .that sorta thing ya know??
this is the distributor cap so #2 goes to #2 spark plug on the engine