All of your videos are insanely fascinating, and have already helped me in finding an issue in my shade tree garage that the over priced dealer couldn't figure out. I owe you a night of beers sir, thank you.. And this series on the H3 is pretty amazing.
KNOWLEDGEABLE Sir ScannerDanner Tutorial great video brilliant 👏👌👍❤️ it Thank you very much Sir ScannerDanner From Nick Ayivor from London England UK 🇬🇧
Just when I think I cant be mind blown again, you do it again. Another priceless video. You've helped me by leaps and bounds. i cant thank you enough for your time and efforts
Another excelent video Paul, every step perfectly and academically explained, you take the teaching and the diagnostics process to the next level, thank you very much for sharing it. You know, some of my classes, I just wanted to finish as soon as possible, but 46 min fly when you are really learning,
Another great video Paul! Loving the old school leak down test. Keep the videos coming. I want to thank you for the chance you have given me to succeed, i have been through a lot in life and this is just the beginning. I'm only 18, i didn't graduate, i battled addiction, i didn't have much going for myself until i found you. I have always loved cars, my father is a mechanic for landrover, i haven't seen him in almost 9 years. You have changed my life and i am forever grateful, i can't thank you enough. happy thanksgiving!!!!!!!!
Great example of old school mechanical concepts mixed with high tech tools. I love my scope, but you still have to know and understand how and why the engine components function.
Excellent video once again. Not many videos that can keep my attention for 45 mins, but your vids do it every time. Keep up the hard work and god bless.
Hi paul , another great vid . I would leak down test all cylinders just to confirm no piston ring faults . Having gone this far , the extra 15 min would make me sleep well . Thanks again for a brill vid .
This is the best leak test I have seen on the internet bar none. I totally agree on a short stroke engine even with a whistle it's insane to get tdc. My only word of caution is on a 14 liter diesel if you put 100 psi in the cylinder and your not on tdc it'll take you for a ride. You have the best videos on the internet. I thought maybe the intake pocket should have been lower when running but idk. Maybe someday I'll have in cylinder wave forms figured out.
Paul, I learned about honesty from you. I liked when you say that even after 2 years you are not comfortable. How many are there who tell others they know everything when they read just manual. You are exception. 1) Million dollar benefit in this video, you gave a tip, that when you compare good to bad cylinder at idle, disable spark of both cylinder, so we are comparing both cylinder with similar characteristics..I have bought video like you who explained this and i remember his name John Thornton.. Even he have not given this technique. 2) I really thought you will stop making such vidoes in your free channel and you might post only to your premium, you proved that i am wrong, you have still got awesome videos to this channel and being worth to be part of this forum as well. You are balancing well between both channel and not letting down .. 3) I do like PICO then snap on especially on compression test with transducer becasue you can zoom to greater extent. Second, you might want to zoom and see the degree at which intake and exhuast is opening the valve. The one that is mechanically bad will open much earlier or in advance.. this is my 2 cents.. Last but not least, you never allow any of ur subscriber to think they learned everything. everynow and then you have got one or morething which is new for others. Unbelievable.. Great Job have no words..
Grate job Paul. This remind me when I was working on my friend truck and he had a miss fire code I went through all the steps. Last call was a engine leak down test. He took it to the shop they told him every thing was good.he told them to do a leak down test n they asked him how he knew about that lol. So they did the test n found bad vales seats in cyl. 3 it was on a 06 5.7L engine grate work thanks for all.also I have the wireless Verus scanner
Hey Paul, great advice on using readiness monitors to see if codes have been cleared recently. On 2005 vehicles and up, you should find mode $0A or mode 10 available in your OBDII Direct menu. This will show DTCs that have been set in the last 400 days. This is very useful when a customer has been to a parts store and the nice young boy clears the codes.
Awesome vid man. Its this stuff that makes your channel the absolute best on youtube for sure. I like that we can learn along with you as you try to get a handle on the in cylinder pressure diagnostics. Speaking as a Tech who LOVES technology and everything new and modern when it comes to diag, I have yet to see anything in a cylinder pressure waveform that a simple leak down test wouldn't reveal lol. I am no expert at it of course, and I am sure as it becomes more common place there will be things that can be learned from it that are unique to it and this is when it will find its home as a standard test. I can say for sure however, that the good old leak down test has NEVER failed me in the field and it has always revealed the correct mechanical issue. Can't wait for the next vid man! You are a rockstar ;)
I agree with all of what you say, Jeffrey. In addition, what impresses me the most about great teachers like Paul and Eric is they are almost always humble, and freely admit uncertainty. You see nothing of the egocentric defensive airs that follow others around....
Hey Paul, was watching a couple of your videos back-to-back. Several Relative Comp tests. Noticed waveform looks cleaner with clamp on the Negative Bat cable. Interesting. HUGE FAN. Thanks for all your guidance.
ScannerDanner @ 35:12 in the oscillations of the manifold near the end, that little downward hump suggest bad valve seating, if you did the same test using your pico you would've had a lot better detail of it because of the pico's better resolution
Paul i diagnosed one of these valve problems one time on a colorado with the same motor using a paddle probe looking at secondary waveform, you could see alot of turbulence in the spark line at idle, Funny thing was, it too was our shop truck and i believe it was also number 4 cylinder bad lol
Top man. i loved both version of the test but the old school tool came out on top on this test for me,but the funny thing is i have a slightly diferent version of the old school tool , i used it for when i had to change valve seals without talking the head off, never gave it a thought for doing leakage test etc. i will have to convert my old school tool now..
Nice video. From my studies, referring to the book "Power Secrets" by Smokey Yunick, a racing engine cylinder leakage should average 5%. The general rule on a good street engine is no more than 20% leakage.
I think the pico is a better choice on the in cylinder waveforms. I dont have one and never used one but theres a reason why John Thornton uses one for his testing.
awesome video Paul! Had a 03 Silverado with I think a 5.3l v8 with a p0300 as well. Found as the engine got hot the valves were sticking in their guides and not closing as they should. Found the problem with a vacuum gauge. Got the tip from your Brother James. You should hook a vac gauge to the h3 and see what it might show.
Misfires affect vacuum. Not a definite confirm. A valve hung up is an ugly miss like detonating well not as bad but a hard miss none the less often accompanied by tap or tick but not always. Did you check for what cyl were missing? P0300 means computer didn't or can't rule out offenders yet. All valves where sticking? Bull stuff. Plus only hot. More unbelievable. I've seen guys fix an intermittent problem real quick and tell me how all checky...... Face palm. Lord why are you tormenting me?
this truck had a P0300 which means a random or intermittent misfire on 2 or more cylinders. while looking at scan data 2 and 7 showed misfiring. but not showing a 302 or 307 code in memory. Did all the checks and found no problem. I took a tip from James Danner and he told me to drive the truck with a vac gauge connected to manifold vacuum. James told me these engines have valve train problems, sticking valves etc. I drove the truck up a long hill, pulled over, let the truck idle and the vac gauge was all over the place. The idle was rough as well but not real bad. We removed the cyl heads and checked the valves on the offending cyls. the valves were snug fitting in the guides and the stems showed galling. We replaced the cyl heads but suggested an engine since the truck had over 200k miles. After the repair all was good. I see the customer with this vehicle all the time since he is a good friend of mine. Face palm back to ya pal. Been doin this for nearly 40 years now and have seen a lot of weird stuff like this.
Paul, another great lesson! Please perform the microphone trick again on your other videos, it really made me feel as if I was standing right next to you! Although, it was obvious in the video, I wish you would have performed a listening comparison between all of the exhaust, intake and cam cover outlets. For us viewers it would have really drove home the point that the problem was in the intake side. Thank you.
i would like to see some vacuum testing i use it for valve testing and clogging converter direction testing on the snap throttle dip and recovery rate. it is such an easy tool to use. i wonder if live scope data on the map sensor can be used for intake valve detection. great video your detailed explainations make it great
Gee, I never thought to disable a good adjacent cylinder when doing in-cylinder pressure testing to evaluate compression pressures. Makes sense, any study needs a good control. Thanks!
You just have to remember if you are doing running tests you now have two dead cylinders instead of one when doing comparisons. The more I've learned about this, the more I realize the greatest advantage with in cylinder pressure analysis is done during cranking, not running because it takes the inertia (if that's the right word) out of the picture from good firing cylinders. The waveform can be altered, or affected by other good cylinders.
I see. Like exposing weakness in fuel delivery when you do a snap throttle, you may not see it at idle. At idle, compression in all cylinders is reduced so a slightly weaker compression in one may not be as obvious. Throw in more air and fuel, and the difference is exposed during hard acceleration or starting. The other thing I wondered about is how cam timing might affect waveforms. Presumably peak pressure shouldn't be affected much because all valves are always closed at that instant. However a bigger gulp of air should have some effect on peak pressures later....
yes, good point. That was never a concern in this case but great point and I should have mentioned that. That will go into Part 2 for sure if there is one. Thanks!
You can watch you map pid specially during a back fire and that's a dead giveaway for a leaky intake valve if you don't have a scanner with misfire counter. Man I can't wait to get one of these compression transducers to try out on some European cars.
I’m surprised that the in-cylinder testing didn’t show as big of a difference between 4 and 5 given how bad the leak-down results were. I guess it did point you in the right direction, but the old school way nailed it. Looking forward to the borescope results.
from what i have learn it helps if you have a Transducer Compression Hoses (High-Strength) because you loose valve data from pressure lost true the compression hose also you have a pico scope right i i think it would have been bettter or what do you think also there is a tdc software that you use so that you can lay it over and see if exhaust or intake are advance or the opposite also with the pc base you could over lay them together and they should be a replicate of each other this is really fresh in my mind because i just took a class on that and the possibilities are endless
How many Bars (or PSI) of air presure did that Snap on tool put in cylinder when you did that test? My tool body is kinda same look, but it shows how much presure you but in and next meter shows, how much of that presure cylinder holds. So that kind tool you have is new to me. Problem with it is that slow valve can close and hold presure in cylinders with air, but in real runing car it may not, so makes misfires. Kinda loosing tool on our toolbox, but still great tool in times, like you show.
hi paul could you have used a vacuum gauge on the inlet manifold to check for a valve problem ,would have been nice to see what results you would have got ,keep the good work , cheers steve uk
Hi Paul, Great videos. I have learnt a great deal from following you. Keep up the good work. Just a thought on your Hummer leaking valve issue. I am not familiar with the Hummer engines, there are not many of them here in Scotland. However before hauling the head off would it not be advisable to check valve clearances first? I remember following "Auto Nerdz", (not sure of the spelling) but they specialise in the Pico scope diagnostics and I seem to remember them doing a case study on a Wrangler Jeep which had very similar symptoms to what you have on the Hummer. Using the Pico scope they traced the problem to a faulty hydraulic tappet that would jack it's self open very slightly. Only a thought!
Great video, I have never pulled the head on a five cylinder, but the six cylinder 4.2, It is much easier to pull the intake manifold up with the head, In my opinion
Oh, and race motors we would like to see under 5% leakdown. Street motors, somewhere around 10% is acceptable, but preferably more like 5 to 8%. Over 10%, there's a problem somewhere. We need a tool that is an oil cap with a small hole and whistle built into it! You could also hook up the pressure transducer to the oil fill hole with a rubber cone adapter, or an oil cap that's been tapped for a pressure transducer to screw into to actually measure the pressure leaking past the rings or broke piston.
Great videos, Scanner Danner. I have used a relative compression test and in-cylinder compression test with the Pico Scope and Snap On products. Some of the professionals are getting away from the cylinder leakage test due to the time it takes to set up. When I used a cylinder leakage test back in my high school auto shop, I was taught to check the exhaust for an exhaust valve leaking air, the intake system for intake valve leaking air, and the oil dipstick or oil filler cap for air leaking past the piston rings just like you mentioned. But also we were taught to open the radiator cap to check for bubbles in the radiator or expansion tank for air leaks that can be due to a bad head gasket or a cracked head or block. Is that last test valid today when it comes to checking for internal cooling leaks from the engine?
Excellent video, thank you for filming this and posting it!! I hope the scope photos come out, I would love to see that valve seat. Will you also be filming the tear down? Thanks again for all your videos, great stuff!!
My class will not be doing the tear down. Our engines class would handle that part. So no video on that part, sorry. Thanks! But look for those scope pics (hopefully)
ScannerDanner Here is a business opportunity for your school Paul..Your class diagnoses the problem, then the engine class does the repair. Both get filmed! If the engine teacher gets on board with his own channel, he can piggyback on your success all the way to the bank lol.
Hello Mr Danner, thanks for that wonderful information.... I have a question: How can I configure my oscilloscope scale to recieve the signal from the trasducer, how much are the min and max values equivalency in volts?
I too would like to see the correlation of engine vacuum here. I'm not convinced a standard vacuum gauge is always sensitive enough, and scoping vacuum with a pressure transducer or MAP sensor might be more revealing.
The scope should have "relative compression test" mode in which it averages amperage for each cylinder and maybe display results as a bar chart. It wouldn't be a big deal for software to do that.
great vidio paul, you would think that with the pressure transducer giving the reading of good compression even running that you would safely rule out lack of compression as the fault and move on to other checks but I like the comment of putting a vacume gauge on it or the wps in the inlet to look for sticking valves. Just shows to more ways / tools you have of compairing readings the better. i was thinking of getting the wps500 but from this vid you dont seem all that keen on the results you have been getting with it, do you think its a worthwhile investment as in the uk its just over $1000 to buy, whats your favourite test/ faults found with it. keep up the good work
I have sort of a question reffering to the running compressions on cyl4 and cyl5. I was diagnosing the same issue on the same vehicle a few months ago, and after ALOT of testing I concluded #2 cyl had a leaking intake valve. But what confused me was that when I did running compression tests (with a conventional compression tester) mine too had very close readings on all cylinders, but with a leaking intake valve shouldnt that be evident on a running compression test? I ending up using smoke in each cylinder when on compression stroke and monitored how much smoke came through the intake manfold and found that cyl2 leaked the most (a ghetto leakdown tests essentially.. lol, but it worked, i was having issues with my leakdown tester at that time)) Now I havent finished all the parts to this video so I apologize if this was covered.
Hi Paul brilliant video, one thing I was thinking, the Verus recording a misfire, would the backfire through the inlet be an actual electrical misfire?..i can see how it can backfire through faulty intake valve...Fred Uk
A misfire that severe I'm sure it would. He is showing a non conventional way of testing that is hard to master and rarely used but can really help save time and diag a fickle sob. If he showed the standard methods I wouldn't be here. Electrical diagnostic are everything in mondern autos.
When I press the gas on my hummer it’s not accelerating or it will only go to 30 -40 and engine light came on. I’m getting a PO411 air injection selenoid is there any way to test to make sure that’s what it is?
I'm really unhappy to hear your comments about not liking the in-cylinder pressure transducer test Paul. Gut instinct tells me this cannot be true! It's a sensitive thing, and somehow has to work. I have no experience with this, but I think we need to try a cranking test, idle test, and snap throttle test to get the most out of the in-cylinder testing. Here's an interesting idea. What if we took shop air, split it two ways, and pressurized the cylinder (regulated to 100 psi or less) with one fork, and hooked up the in-cylinder pressure transducer with the other fork? At the very least, it would be a scoped leakdown test. I think I just invented that! LOL
I like your idea on this one..very "out of the box" thinking :) We would need hundreds or thousands of case studies with this method to make valid and scientifically valid data…but most likely the transducer would be redundant and reveal nothing that the leak down wouldn't already tell you.
Probably would just be an electronic leak down test that's recordable. But maybe something interesting would show up. Maybe you could rotate the engine by hand while pumping 50 psi into the cylinder and scoping pressure. As the valves opened or closed, maybe weird airflow oscillations would occur as the seat leaks. I just don't understand why we don't see it in a running waveform!
I still think that even if the transducer reveals little details like "carbon deposit holding intake valve open" while leak down test reveals "intake valve stuck open" the outcome is the same. Verification of mechanical issue resulting in head removal or condemning piston rings. :)
I think we could measure pressure at the oil cap to condemn or rule out rings and pistons, once we know what a good motor's pressure looks like. I don't mind that the result is the same, an accurate diagnosis of a valve problem. But I want to use compression waveforms to definitively determine if a valve leaks mildly, and which valve it is. Perhaps a simultaneous MAP or exhaust pressure test would help prove it out.
hey Paul you should sale those adapters on your tool page some of us cant get our truck guy to sale those to us. I have the versus and the verdict both the verdict is just like the versus edge but all blue tooth its so nice but its only 2 channel scope that's the down side but man it works good. snap on stopped the updates on it though. so 18.4 is the last i can get. its a shame really. but my tool truck guy wont sale those adapters or the stylus you have i would love to get one. try to see about it maybe you could help some of us out. just a thought. Thanks for all you do its been a big help to me and my boy. we really keep going back and checking for things we are not sure of and always watching for new videos and the old ones we have not seen yet. lol your awesome thanks again and keep it up please.
Actually, raising the RPM to 1500 wasn't necessary to make the miss go away. I myself am an ex GM dealer tech, and what I found when ran into these with this particular problem is simply raising the RPM to 900-1,000 RPM's was enough to make the miss go away. It's actually kinda funny to me that GM still has this problem in the 08 model year, cause 07 and up 5 cylinders were supposed to have the updated cylinder head (GM recommended replacing whole head for the 5 cylinders, which already had new valves, seats, springs, and all put on it when you got it) installed at the factory. Key word there being SUPPOSED.
I'm curious as to what your fuel trim and o2 readings look like with this type of misfire? I would imagine the o2 is showing very rich with the fuel trim trying to lean the mixture.
I would like to ask you a question hopefully i would get and answer. I have a verus pro and i just buy the EETM303A05A inductive RPM tester. But i did not get any in fo on how to used this adapter it will check secondary ingnition. My question is do i have to connect the ground cable when i used the RPM ADAPTER. I thank youu very much for your responds.
I don't use that adapter much, and I am pretty sure you cannot get a waveform from it. It only provides the scope with an RPM input. You can trigger off of the RPM signal using the scope but it will not show you anything on the screen but a white + sign indicating you are triggering from the RPM data.
many thanks for such awesome videos. can you please tell me what is the pressure value should I have on my injection rail. my Hummer h3 2007 is running rich and has random misfire p0300 only when I hit the pedal. and the code disappear when the vehicle is idling.
+ScannerDanner well, i've checked your other cool videos already for Hummer H3 and I will need a 10K USD equipments to perform those tests and diagnostics. XD. anyways it gave me a better understanding for valves leakage types and how to indicate each type. also a local GM mechanic said this could be a fuel pump or worn injectors problem, so yesterday i've built my fuel pressure test rig and i found that i have 60 Psi in the injectors rail. and it is constant under all conditions. most notably that i have an DIY fuel pump assy. consist of two fuel pumps and one fuel pressure regulator all connected to a common tiny manifold then i have a filter outside the tank. this is the common setup here (Iraq) because the OEM fuel pump assy. is not available here. any ideas on where to start troubleshooting ? because mechanics here are having try-and-error approach and i have to pay for all their error tries...
+Mohammed al-ani sounds just like here my friend. If you're psi is steady at 60 even under load, then it's not the fuel pump. I should have asked. Is this the 5 cylinder in-line engine? (like in my video)
hey i know this is an old video but i am a new subscriber and am trying to learn how to use my scope (snapon modis ultra) and in another video you had mentioned that you needed to use the low amp probe on a starter positive wire to the battery. just trying to figure out how you can do the same test with using the amp probe on the battery ground. if you scanner or anyone has an answer for me that would be appreciated.
Jeffrey Wilson I think it will act like the needle of a vacuum gauge... since a map sensor is pretty much just an electronic vacuum gauge. Intake vacuum fluctuations should be visible when graphing a map signal. As with any method, one needs to know how to interpret the readings by knowing the good the bad and the "what the hell"? LOL
***** Thanks Thomas..ya I hear ya..for those of use used to reading analog needle fluctuations on a gauge reading a graphed MAP sensor is a whole different animal lol
Hi Paul I set up the compression test sinked with the trigger wire on a mini cooper s just to practice getting the waveform on my vantage pro but I find on cranking the spark was not at tdc this was a good running car no faults this car has a 3 wire waste spark system am I doing something wrong or is this normal to have a spark but for tdc ? Ps it has a super charger if that makes a difference.
I am directing all help requests to my forum. Sign up (it's free) and create a new post. Be sure to add a name under "alias" as this is the name that will appear in the post. Here is the link to the forum. www.scannerdanner.com/ForumRetrieve.aspx?ForumID=3226 Thanks!
I would like to see this too. Maybe even show the in cylinder compression test waveform with the manifold vacuum waveform. You might be able to show that a bump in manifold pressure corresponds to the peak in compression on that cylinder or something along those lines.
Dennis Rindlisbach Vacuum gauge can reveal a valve seating issue for sure. The key is having a really good and reliable gauge. I have used many gauges over the years and unless you know the gauge is 100% good, there can be to many variables and unreliable readings. But with a good gauge, and exhaust valve seating issue will show up as low vacuum at idle, but pretty steady needle without many fluctuations. An intake valve seating issue allows air to return into the intake manifold causing a sort of "back pressure". This back pressure decreases the vacuum in the manifold, so it shows up on your gauge as a 1-7 in. hg vacuum drop every time the cylinder compresses (needle fluctuation) Vacuum gauge testing is still a valuable and valid test method today, but because of the possibility of variables, there are other tests that are just more reliable.
I have a P0307 briefly pending, then seconds later a P0300 stored on a 2000 5.7 GMC savana only around 2000+ rpm. SES light starts flashing until returning to idle speed. Where should I start? problem is I dont feel a miss. I restart the engine and the pending code goes away until High rpms again. I cleaned the distributor, installed new plugs, tested wires, around 2k ohms. i kind of want to change the cap and rotor and ignition coil, but maybe its a faulty cam sensor confusing the computer?
first I'm not sure 40 percent is considered good. That's just what that gauge said. And no, you would not hear that much air coming from the throttle body on a good cylinder
as paul said , every engine has different spec.. i use to do this all the time in aircraft engine, and the law allow as 25% leak and yes you could hear it
I know this is an old video, but my first time seeing it. I noticed that when you set your cursors during the firstrelative compression test, the #1 cylinder cursor reading on your scope was 1.44 (144amps), and on #4 the cursor reading was 1.27 (127 amps). Mathematically this is an 11.8% differential between the two cylinders. But when you did the compression check, the #5 cylinder was at 150psi and the#4 was at 125psi for a 16.7% differential. I want to assume that the difference between the compression check and relative compression check is because #5 cylinder, which you didn't measure on the scope, would have been higher then#1 cylinder, or approximately 1.51 (151amps), which would have made a 16.7% difference between high and low cylinders. Is my assumption correct? Also, apart from the fact that you are in a classroom, can I rely upon the fact that there is an 11.8% (16.7%) difference between the high and low cylinder current draw and skip the compression/leak down test or is that a shortcut to trouble? Basically is the mathematical calculations based on current draw reliable enough for a diagnostics? Thanks
It is becoming more and more difficult to answer questions here. I have 80,000 people asking me for help now. So I have created a forum to help you guys better. It is free to join and we can exchange pictures, wiring diagrams and waveforms if needed to help guide you through the process of troubleshooting your vehicle. Thank you so much! Hope to see you there. Paul Danner (ScannerDanner) www.scannerdanner.com/forum/post-your-repair-questions-here.html
Paul I agree with you about the interpretation of in cylinder wave form very hard to make the call, a mechanic from other shop call me to diagnoses a ford Econoline the owner of vehicle had this at the ford dealer for this misfire on single cylinder they replace new plugs wires, injector and new coil pack misfire still present ,and they conclude it was mechanical problem they suggested to replace engine, they took it to a independent shop so when I was checking cylinder contribution on scanner only a single cylinder was misfiring under 1500 rpm only I did in cylinder pressure traducer , to compare different cylinder and expansion packet on valves looks different on misfire cylinder then the rest, I make the call bad engine . After they replace the engine same result misfire there same rpm same cylinder i did not what to do any way they call for some else to diagnose and he said it was bad coli pack they replace it and misfire gone . man I feel so bad my big question is how the coil did it it was brand new motor craft and is waste spark how did it occurred at idle and one cylinder only and not companion, why only idle I know the common fail is higher rpm because of demand of kv, I would like to hear from you about this from you how is theory behind it . will account that I am not good with my scope with pressure traducer and ignition system, may be the subject is out but I would appreciate your idea, nice video
Well you assumed a very expensive part was bad with an unreliable test in my opinion. We all make mistakes admitting and learning from them is a characteristic of a good tech. I am really careful with my guilty verdicts. I gotta be sure unless part is very cheap and time to confirm outways heavily. Its an engine bro. Be more careful with your customers money... And your shops as an honest one would eat it. WORD of MOUTH you dig. A damn 4.2 envoy kicked me hard with a damn sneaky coil. Recall for valves leaking too... Go with it?? Nope not sure yet. Running compression test time.. all good all time. No go keep digging.
How did it fail?? Huh? Cracked it, defective, abused during testing who knows who cares. Why was companion cyl. Ok? Because its output was perhaps. Never assume. Parts DON'T fail the same way all the time. I've seen a many coils that way buddy. Replaced many new parts again. Watch guys sit n wonder what to throw now when parts run out completely ignoing the possibility of installing a bad part and there best guess method actually was accurate. LoL not funny tho. I hate those noobs. Any monkey can replace parts
When I put on a bad part I know it cause I diagnose. I'm a tester not a guess-er. :) you are a human. It was a mistake and bad judgment. Put the fancy scope down and do a real test. Scopes are good but electrical stuff does some strait unearthly impossible weird stuff sometimes. If cylinder miss its valves and piston wouldn't move at same speed as rest. Think about it. Leak down compression off and on.
wai2machine823 history of vehicle for that misfire first was in independent shop they replace plugs and wires same no changes , second the the owner of the vehicle took it to the dealer they said wires and plugs were not genuine they are garbage we have to install from factory they did same misfire, the dealer did second call to owner saying they needed to replace the coil pack and the injector they did and misfire still present genuine parts, they got to the conclusion mechanical problem, third the owner of the vehicle took it to one of my friend shop and she was not asking for diagnostic she had the engine on the back of the truck already she wanted installation, because I have pressure transducer my friend call me to do some testing as a confirmation, I did test all current amp on all injectors and coil pack also I induce a misfire on each cylinder to check if computer was reading accurate remember misfire was under 1500 rpm only , I never scope the secondary side of the coil pack but I spray water around wires and coil pack no physical damage to coil at all , know is easy to know that was the problem because we already know.if the only cylinder was showing me differences on expansion pack was the one had the misfire comparing to the others . If I had started this diagnostic my self I do not know if I had done the call of engine.
I don't like that the piston is not at TDC. I think it might be easy for the compressor to push the piston down that way. When the piston is at true TDC, the rod is pretty much aligned straight up and down, and makes it real hard for the piston to move. I use a slick spring-loaded TDC indicator for that from Innovative Products of America, part# 7886, 7880, or 7891. It's a nice luxury.
As long as you hold the wrench firmly this is a perfectly fine way of measuring leakdown. In fact I purposely test leakdown by this method because i believe it to be much better than TDC method since TDC only measure leakdown in fraction of the cylinder while measuring as soon as the valves close measures the entire clylinder and can potentially find compromises in the cylinder wall that would be missed by testing at TDC -e.g. "behind" the piston.
But isn't most of the bore wear at TDC? I suppose if you started at BDC and slowly rotated it to TDC while watching the gage would be ideal. A "moving" leak down test might find issues only occurring in some parts of the bore.
It is becoming more and more difficult to answer questions here. I have 80,000 people asking me for help now. So I have created a forum to help you guys better. It is free to join and we can exchange pictures, wiring diagrams and waveforms if needed to help guide you through the process of troubleshooting your vehicle. Thank you so much! Hope to see you there. Paul Danner (ScannerDanner) www.scannerdanner.com/forum/post-your-repair-questions-here.html
All of your videos are insanely fascinating, and have already helped me in finding an issue in my shade tree garage that the over priced dealer couldn't figure out. I owe you a night of beers sir, thank you.. And this series on the H3 is pretty amazing.
+Gmtail thanks man!
KNOWLEDGEABLE Sir ScannerDanner
Tutorial great video brilliant 👏👌👍❤️ it
Thank you very much Sir ScannerDanner
From Nick Ayivor from London England UK 🇬🇧
Just when I think I cant be mind blown again, you do it again. Another priceless video. You've helped me by leaps and bounds. i cant thank you enough for your time and efforts
Another excelent video Paul, every step perfectly and academically explained, you take the teaching and the diagnostics process to the next level, thank you very much for sharing it. You know, some of my classes, I just wanted to finish as soon as possible, but 46 min fly when you are really learning,
Another great video Paul! Loving the old school leak down test. Keep the videos coming. I want to thank you for the chance you have given me to succeed, i have been through a lot in life and this is just the beginning. I'm only 18, i didn't graduate, i battled addiction, i didn't have much going for myself until i found you. I have always loved cars, my father is a mechanic for landrover, i haven't seen him in almost 9 years. You have changed my life and i am forever grateful, i can't thank you enough. happy thanksgiving!!!!!!!!
Thank you Max. May this path you're now walking cross paths with your dad someday.
Great example of old school mechanical concepts mixed with high tech tools. I love my scope, but you still have to know and understand how and why the engine components function.
Excellent video once again. Not many videos that can keep my attention for 45 mins, but your vids do it every time.
Keep up the hard work and god bless.
Hi paul , another great vid . I would leak down test all cylinders just to confirm no piston ring faults . Having gone this far , the extra 15 min would make me sleep well . Thanks again for a brill vid .
This is the best leak test I have seen on the internet bar none. I totally agree on a short stroke engine even with a whistle it's insane to get tdc. My only word of caution is on a 14 liter diesel if you put 100 psi in the cylinder and your not on tdc it'll take you for a ride. You have the best videos on the internet. I thought maybe the intake pocket should have been lower when running but idk. Maybe someday I'll have in cylinder wave forms figured out.
Paul, I learned about honesty from you. I liked when you say that even after 2 years you are not comfortable. How many are there who tell others they know everything when they read just manual. You are exception.
1) Million dollar benefit in this video, you gave a tip, that when you compare good to bad cylinder at idle, disable spark of both cylinder, so we are comparing both cylinder with similar characteristics..I have bought video like you who explained this and i remember his name John Thornton.. Even he have not given this technique.
2) I really thought you will stop making such vidoes in your free channel and you might post only to your premium, you proved that i am wrong, you have still got awesome videos to this channel and being worth to be part of this forum as well. You are balancing well between both channel and not letting down ..
3) I do like PICO then snap on especially on compression test with transducer becasue you can zoom to greater extent. Second, you might want to zoom and see the degree at which intake and exhuast is opening the valve. The one that is mechanically bad will open much earlier or in advance.. this is my 2 cents..
Last but not least, you never allow any of ur subscriber to think they learned everything. everynow and then you have got one or morething which is new for others. Unbelievable.. Great Job have no words..
Grate job Paul. This remind me when I was working on my friend truck and he had a miss fire code I went through all the steps. Last call was a engine leak down test. He took it to the shop they told him every thing was good.he told them to do a leak down test n they asked him how he knew about that lol. So they did the test n found bad vales seats in cyl. 3 it was on a 06 5.7L engine grate work thanks for all.also I have the wireless Verus scanner
Like always Paul, excellent video..
Learned a thing or two from watching this.Keep up the great work Paul..
Thanks for your time.
Great video Paul! look forward for the second part! The borescope sounds interesting!! Thanks again for sharing your knowledge with us!
Fantastic job, I fall in love with this field after all information u provide, thanx a lot
Hey Paul, great advice on using readiness monitors to see if codes have been cleared recently. On 2005 vehicles and up, you should find mode $0A or mode 10 available in your OBDII Direct menu. This will show DTCs that have been set in the last 400 days. This is very useful when a customer has been to a parts store and the nice young boy clears the codes.
Awesome vid man. Its this stuff that makes your channel the absolute best on youtube for sure. I like that we can learn along with you as you try to get a handle on the in cylinder pressure diagnostics. Speaking as a Tech who LOVES technology and everything new and modern when it comes to diag, I have yet to see anything in a cylinder pressure waveform that a simple leak down test wouldn't reveal lol. I am no expert at it of course, and I am sure as it becomes more common place there will be things that can be learned from it that are unique to it and this is when it will find its home as a standard test. I can say for sure however, that the good old leak down test has NEVER failed me in the field and it has always revealed the correct mechanical issue. Can't wait for the next vid man! You are a rockstar ;)
I agree with all of what you say, Jeffrey. In addition, what impresses me the most about great teachers like Paul and Eric is they are almost always humble, and freely admit uncertainty. You see nothing of the egocentric defensive airs that follow others around....
Hey Paul, was watching a couple of your videos back-to-back. Several Relative Comp tests. Noticed waveform looks cleaner with clamp on the Negative Bat cable. Interesting. HUGE FAN. Thanks for all your guidance.
ScannerDanner @ 35:12 in the oscillations of the manifold near the end, that little downward hump suggest bad valve seating, if you did the same test using your pico you would've had a lot better detail of it because of the pico's better resolution
And awesome video as usual :)
Paul i diagnosed one of these valve problems one time on a colorado with the same motor using a paddle probe looking at secondary waveform, you could see alot of turbulence in the spark line at idle, Funny thing was, it too was our shop truck and i believe it was also number 4 cylinder bad lol
Top man.
i loved both version of the test but the old school tool came out on top on this test for me,but the funny thing is i have a slightly diferent version of the old school tool , i used it for when i had to change valve seals without talking the head off, never gave it a thought for doing leakage test etc.
i will have to convert my old school tool now..
thanks Paul, for so many help you gave through your video channel.
Wow. This is great you must have the best techs coming out of your class
A lot of my online students now have TH-cam channels of their own 😉
Thanks man
Great thorough and detailed video..
Nice one Mr.Danner.
God Bless you Paul. Thank you for everything. I am actually a Professional Technician because of you.
Nice video. From my studies, referring to the book "Power Secrets" by Smokey Yunick, a racing engine cylinder leakage should average 5%. The general rule on a good street engine is no more than 20% leakage.
I think the pico is a better choice on the in cylinder waveforms. I dont have one and never used one but theres a reason why John Thornton uses one for his testing.
yeah it is a much better choice if you have one in hand, it has a lot more definition in the waveform
Looking forward to Part 2, thanks for posting this video
Thanks for the information you put on here,its a good source of information,its a credit to you.
Cheers Brett
awesome video Paul! Had a 03 Silverado with I think a 5.3l v8 with a p0300 as well. Found as the engine got hot the valves were sticking in their guides and not closing as they should. Found the problem with a vacuum gauge. Got the tip from your Brother James. You should hook a vac gauge to the h3 and see what it might show.
Misfires affect vacuum. Not a definite confirm. A valve hung up is an ugly miss like detonating well not as bad but a hard miss none the less often accompanied by tap or tick but not always. Did you check for what cyl were missing? P0300 means computer didn't or can't rule out offenders yet. All valves where sticking? Bull stuff. Plus only hot. More unbelievable. I've seen guys fix an intermittent problem real quick and tell me how all checky...... Face palm. Lord why are you tormenting me?
this truck had a P0300 which means a random or intermittent misfire on 2 or more cylinders. while looking at scan data 2 and 7 showed misfiring. but not showing a 302 or 307 code in memory. Did all the checks and found no problem. I took a tip from James Danner and he told me to drive the truck with a vac gauge connected to manifold vacuum. James told me these engines have valve train problems, sticking valves etc. I drove the truck up a long hill, pulled over, let the truck idle and the vac gauge was all over the place. The idle was rough as well but not real bad. We removed the cyl heads and checked the valves on the offending cyls. the valves were snug fitting in the guides and the stems showed galling. We replaced the cyl heads but suggested an engine since the truck had over 200k miles. After the repair all was good. I see the customer with this vehicle all the time since he is a good friend of mine. Face palm back to ya pal. Been doin this for nearly 40 years now and have seen a lot of weird stuff like this.
Face palming co workers. Don't know all you did. A vacuum check is a pointer tho not a conclusion. Rapid fluctuations are valves I believe.
I can fix any mis with a new engine. Unless ign inj driver.. ;))).
Awesome video Paul, keep up the great work. It greatly appreciated!!
Paul, another great lesson! Please perform the microphone trick again on your other videos, it really made me feel as if I was standing right next to you! Although, it was obvious in the video, I wish you would have performed a listening comparison between all of the exhaust, intake and cam cover outlets. For us viewers it would have really drove home the point that the problem was in the intake side. Thank you.
i would like to see some vacuum testing i use it for valve testing and clogging converter direction testing on the snap throttle dip and recovery rate. it is such an easy tool to use. i wonder if live scope data on the map sensor can be used for intake valve detection. great video your detailed explainations make it great
Gee, I never thought to disable a good adjacent cylinder when doing in-cylinder pressure testing to evaluate compression pressures. Makes sense, any study needs a good control. Thanks!
You just have to remember if you are doing running tests you now have two dead cylinders instead of one when doing comparisons.
The more I've learned about this, the more I realize the greatest advantage with in cylinder pressure analysis is done during cranking, not running because it takes the inertia (if that's the right word) out of the picture from good firing cylinders. The waveform can be altered, or affected by other good cylinders.
I see. Like exposing weakness in fuel delivery when you do a snap throttle, you may not see it at idle. At idle, compression in all cylinders is reduced so a slightly weaker compression in one may not be as obvious. Throw in more air and fuel, and the difference is exposed during hard acceleration or starting. The other thing I wondered about is how cam timing might affect waveforms. Presumably peak pressure shouldn't be affected much because all valves are always closed at that instant. However a bigger gulp of air should have some effect on peak pressures later....
you can also use smoke test into the cylinder 4 directly Paul..to nail the issue.
During a leakdown test also pull the radiator cap off and check for bubbles, for a leaking head gasket
yes, good point. That was never a concern in this case but great point and I should have mentioned that.
That will go into Part 2 for sure if there is one. Thanks!
ScannerDanner What do you mean if there is one?? lol…we want part 2 with bore scope pics! haha
You can watch you map pid specially during a back fire and that's a dead giveaway for a leaky intake valve if you don't have a scanner with misfire counter. Man I can't wait to get one of these compression transducers to try out on some European cars.
I’m surprised that the in-cylinder testing didn’t show as big of a difference between 4 and 5 given how bad the leak-down results were. I guess it did point you in the right direction, but the old school way nailed it. Looking forward to the borescope results.
from what i have learn it helps if you have a Transducer Compression Hoses (High-Strength) because you loose valve data from pressure lost true the compression hose also you have a pico scope right i i think it would have been bettter or what do you think also there is a tdc software that you use so that you can lay it over and see if exhaust or intake are advance or the opposite also with the pc base you could over lay them together and they should be a replicate of each other this is really fresh in my mind because i just took a class on that and the possibilities are endless
How many Bars (or PSI) of air presure did that Snap on tool put in cylinder when you did that test?
My tool body is kinda same look, but it shows how much presure you but in and next meter shows, how much of that presure cylinder holds. So that kind tool you have is new to me.
Problem with it is that slow valve can close and hold presure in cylinders with air, but in real runing car it may not, so makes misfires. Kinda loosing tool on our toolbox, but still great tool in times, like you show.
Outstanding presentation!
Hi paul this mechanical problem would it have shown up on a vacuum gauge sandy ps what is the video mic u r using
hi paul could you have used a vacuum gauge on the inlet manifold to check for a valve problem ,would have been nice to see what results you would have got ,keep the good work , cheers steve uk
Hi Paul, Great videos. I have learnt a great deal from following you. Keep up the good work.
Just a thought on your Hummer leaking valve issue. I am not familiar with the Hummer engines, there are not many of them here in Scotland. However before hauling the head off would it not be advisable to check valve clearances first? I remember following "Auto Nerdz", (not sure of the spelling) but they specialise in the Pico scope diagnostics and I seem to remember them doing a case study on a Wrangler Jeep which had very similar symptoms to what you have on the Hummer. Using the Pico scope they traced the problem to a faulty hydraulic tappet that would jack it's self open very slightly. Only a thought!
good thinking
Do you mind if you check o2 sensor 1 voltage for bank one and bank 2 to see what we have , lean misfire or rich
If we were to rate your videos this one would be in the top....hope we can see the borescope
The fourth place to check for air coming out is another cylinder. Cracked heads or blown head gasket can leak into an adjacent cylinder.
Great classes. I paid 14 grand for 9 months at ati..... I regret it everyday.
I was surprised to see that the 90psi you had on the leak down gauge pushing down on the piston didn't rotate the engine like I've seen before.
Great video, I have never pulled the head on a five cylinder, but the six cylinder 4.2, It is much easier to pull the intake manifold up with the head, In my opinion
Oh, and race motors we would like to see under 5% leakdown. Street motors, somewhere around 10% is acceptable, but preferably more like 5 to 8%. Over 10%, there's a problem somewhere.
We need a tool that is an oil cap with a small hole and whistle built into it! You could also hook up the pressure transducer to the oil fill hole with a rubber cone adapter, or an oil cap that's been tapped for a pressure transducer to screw into to actually measure the pressure leaking past the rings or broke piston.
Paul, thank you for your work & time.
Were you able to look for turbulances, on the secondary spark line which would indicate vlave sealing issues?
Great videos, Scanner Danner. I have used a relative compression test and in-cylinder compression test with the Pico Scope and Snap On products. Some of the professionals are getting away from the cylinder leakage test due to the time it takes to set up. When I used a cylinder leakage test back in my high school auto shop, I was taught to check the exhaust for an exhaust valve leaking air, the intake system for intake valve leaking air, and the oil dipstick or oil filler cap for air leaking past the piston rings just like you mentioned. But also we were taught to open the radiator cap to check for bubbles in the radiator or expansion tank for air leaks that can be due to a bad head gasket or a cracked head or block. Is that last test valid today when it comes to checking for internal cooling leaks from the engine?
Wow!, Man you are a really good teacher, God bless you!, you are s really good tech
Excellent video, thank you for filming this and posting it!! I hope the scope photos come out, I would love to see that valve seat. Will you also be filming the tear down? Thanks again for all your videos, great stuff!!
My class will not be doing the tear down. Our engines class would handle that part. So no video on that part, sorry. Thanks! But look for those scope pics (hopefully)
ScannerDanner Here is a business opportunity for your school Paul..Your class diagnoses the problem, then the engine class does the repair. Both get filmed! If the engine teacher gets on board with his own channel, he can piggyback on your success all the way to the bank lol.
Hello Mr Danner, thanks for that wonderful information.... I have a question: How can I configure my oscilloscope scale to recieve the signal from the trasducer, how much are the min and max values equivalency in volts?
You have no know the transducer specs. They are all different
Would have been cool to run a dynamic compression test. Just to get an idea where the problem lies intake or exhaust?
I too would like to see the correlation of engine vacuum here. I'm not convinced a standard vacuum gauge is always sensitive enough, and scoping vacuum with a pressure transducer or MAP sensor might be more revealing.
Thats a common problem! i was a former Hummer Tech for Gm and seen lots of them with that code!
The scope should have "relative compression test" mode in which it averages amperage for each cylinder and maybe display results as a bar chart. It wouldn't be a big deal for software to do that.
could you use the vantage pro and another of low amp probe and do the same relative compression test
great information
great vidio paul, you would think that with the pressure transducer giving the reading of good compression even running that you would safely rule out lack of compression as the fault and move on to other checks but I like the comment of putting a vacume gauge on it or the wps in the inlet to look for sticking valves. Just shows to more ways / tools you have of compairing readings the better. i was thinking of getting the wps500 but from this vid you dont seem all that keen on the results you have been getting with it, do you think its a worthwhile investment as in the uk its just over $1000 to buy, whats your favourite test/ faults found with it. keep up the good work
Thanks for the video Paul.
So can i use my 60A PICO clamp at my work on this test too(petrol cars) or do i need to use that high A clamp on that tool?
I have sort of a question reffering to the running compressions on cyl4 and cyl5.
I was diagnosing the same issue on the same vehicle a few months ago, and after ALOT of testing I concluded #2 cyl had a leaking intake valve. But what confused me was that when I did running compression tests (with a conventional compression tester) mine too had very close readings on all cylinders, but with a leaking intake valve shouldnt that be evident on a running compression test? I ending up using smoke in each cylinder when on compression stroke and monitored how much smoke came through the intake manfold and found that cyl2 leaked the most (a ghetto leakdown tests essentially.. lol, but it worked, i was having issues with my leakdown tester at that time))
Now I havent finished all the parts to this video so I apologize if this was covered.
The rounded bit shows a intake valve struggling to settle on its seat.
Its very subtle and could be just a characteristic.
my thought exacly
Besides scanner danner premium is there online courses available for RTI
Dan the man. Like a younger me. :))))
Hi Paul brilliant video, one thing I was thinking, the Verus recording a misfire, would the backfire through the inlet be an actual electrical misfire?..i can see how it can backfire through faulty intake valve...Fred Uk
the backfire I mentioned early in the video was actually not a backfire. It was an exhaust leak very near or at the exhaust manifold. sorry about that
ScannerDanner Hi Paul, sorry my fault, I didn't mean backfire I meant the firing through the inlet valve, would that cause a fault code...Fred uk
A misfire that severe I'm sure it would. He is showing a non conventional way of testing that is hard to master and rarely used but can really help save time and diag a fickle sob. If he showed the standard methods I wouldn't be here. Electrical diagnostic are everything in mondern autos.
Hello Paul , can all the test you did with the Verus on the vehicle , be done with a Vertic D7 ? Thanks .
When I press the gas on my hummer it’s not accelerating or it will only go to 30 -40 and engine light came on. I’m getting a PO411 air injection selenoid is there any way to test to make sure that’s what it is?
I'm really unhappy to hear your comments about not liking the in-cylinder pressure transducer test Paul. Gut instinct tells me this cannot be true! It's a sensitive thing, and somehow has to work. I have no experience with this, but I think we need to try a cranking test, idle test, and snap throttle test to get the most out of the in-cylinder testing.
Here's an interesting idea. What if we took shop air, split it two ways, and pressurized the cylinder (regulated to 100 psi or less) with one fork, and hooked up the in-cylinder pressure transducer with the other fork? At the very least, it would be a scoped leakdown test. I think I just invented that! LOL
I like your idea on this one..very "out of the box" thinking :) We would need hundreds or thousands of case studies with this method to make valid and scientifically valid data…but most likely the transducer would be redundant and reveal nothing that the leak down wouldn't already tell you.
Probably would just be an electronic leak down test that's recordable. But maybe something interesting would show up. Maybe you could rotate the engine by hand while pumping 50 psi into the cylinder and scoping pressure. As the valves opened or closed, maybe weird airflow oscillations would occur as the seat leaks. I just don't understand why we don't see it in a running waveform!
I still think that even if the transducer reveals little details like "carbon deposit holding intake valve open" while leak down test reveals "intake valve stuck open" the outcome is the same. Verification of mechanical issue resulting in head removal or condemning piston rings. :)
I think we could measure pressure at the oil cap to condemn or rule out rings and pistons, once we know what a good motor's pressure looks like. I don't mind that the result is the same, an accurate diagnosis of a valve problem. But I want to use compression waveforms to definitively determine if a valve leaks mildly, and which valve it is. Perhaps a simultaneous MAP or exhaust pressure test would help prove it out.
hey Paul you should sale those adapters on your tool page some of us cant get our truck guy to sale those to us. I have the versus and the verdict both the verdict is just like the versus edge but all blue tooth its so nice but its only 2 channel scope that's the down side but man it works good. snap on stopped the updates on it though. so 18.4 is the last i can get. its a shame really. but my tool truck guy wont sale those adapters or the stylus you have i would love to get one. try to see about it maybe you could help some of us out. just a thought. Thanks for all you do its been a big help to me and my boy. we really keep going back and checking for things we are not sure of and always watching for new videos and the old ones we have not seen yet. lol your awesome thanks again and keep it up please.
Thank you! Which adapters my friend?
Actually, raising the RPM to 1500 wasn't necessary to make the miss go away. I myself am an ex GM dealer tech, and what I found when ran into these with this particular problem is simply raising the RPM to 900-1,000 RPM's was enough to make the miss go away. It's actually kinda funny to me that GM still has this problem in the 08 model year, cause 07 and up 5 cylinders were supposed to have the updated cylinder head (GM recommended replacing whole head for the 5 cylinders, which already had new valves, seats, springs, and all put on it when you got it) installed at the factory. Key word there being SUPPOSED.
I'm curious as to what your fuel trim and o2 readings look like with this type of misfire? I would imagine the o2 is showing very rich with the fuel trim trying to lean the mixture.
I would really like to see them too but they won't be accurate due to that exhaust leak ahead of the O2 sensors
There are 4 spots to check when doing leak down. Radiator as well. blown head gaskets will cause leaks into cooling system.
I would like to ask you a question hopefully i would get and answer. I have a verus pro and i just buy the EETM303A05A inductive RPM tester. But i did not get any in fo on how to used this adapter it will check secondary ingnition. My question is do i have to connect the ground cable when i used the RPM ADAPTER. I thank youu very much for your responds.
I don't use that adapter much, and I am pretty sure you cannot get a waveform from it. It only provides the scope with an RPM input. You can trigger off of the RPM signal using the scope but it will not show you anything on the screen but a white + sign indicating you are triggering from the RPM data.
many thanks for such awesome videos.
can you please tell me what is the pressure value should I have on my injection rail.
my Hummer h3 2007 is running rich and has random misfire p0300 only when I hit the pedal.
and the code disappear when the vehicle is idling.
+Mohammed al-ani I'm showing 50-57 psi
these are known for valve problems, have you seen my Hummer series?
+ScannerDanner well, i've checked your other cool videos already for Hummer H3 and I will need a 10K USD equipments to perform those tests and diagnostics. XD.
anyways it gave me a better understanding for valves leakage types and how to indicate each type.
also a local GM mechanic said this could be a fuel pump or worn injectors problem, so yesterday i've built my fuel pressure test rig and i found that i have 60 Psi in the injectors rail. and it is constant under all conditions.
most notably that i have an DIY fuel pump assy. consist of two fuel pumps and one fuel pressure regulator all connected to a common tiny manifold then i have a filter outside the tank.
this is the common setup here (Iraq) because the OEM fuel pump assy. is not available here.
any ideas on where to start troubleshooting ? because mechanics here are having try-and-error approach and i have to pay for all their error tries...
+Mohammed al-ani sounds just like here my friend.
If you're psi is steady at 60 even under load, then it's not the fuel pump.
I should have asked. Is this the 5 cylinder in-line engine? (like in my video)
+ScannerDanner Premium yea it is the 3.7L 5 cylinders inline engine ( Vortec).
UTI does this with live cars they have for years
hey i know this is an old video but i am a new subscriber and am trying to learn how to use my scope (snapon modis ultra) and in another video you had mentioned that you needed to use the low amp probe on a starter positive wire to the battery. just trying to figure out how you can do the same test with using the amp probe on the battery ground. if you scanner or anyone has an answer for me that would be appreciated.
map sensor can be used for quick intake valve checking.
please explain for those who don't know
Jeffrey Wilson I think it will act like the needle of a vacuum gauge... since a map sensor is pretty much just an electronic vacuum gauge. Intake vacuum fluctuations should be visible when graphing a map signal. As with any method, one needs to know how to interpret the readings by knowing the good the bad and the "what the hell"? LOL
***** Thanks Thomas..ya I hear ya..for those of use used to reading analog needle fluctuations on a gauge reading a graphed MAP sensor is a whole different animal lol
Jeffrey Wilson
funny you say that. vacuum gauge and map sensor on a scope is being uploaded right now. I was learning on this one too!
Paul…excellent! Very excited to see this! Talk about perfect timing :)
Hi Paul I set up the compression test sinked with the trigger wire on a mini cooper s just to practice getting the waveform on my vantage pro but I find on cranking the spark was not at tdc this was a good running car no faults this car has a 3 wire waste spark system am I doing something wrong or is this normal to have a spark but for tdc ? Ps it has a super charger if that makes a difference.
I am directing all help requests to my forum. Sign up (it's free) and create a new post. Be sure to add a name under "alias" as this is the name that will appear in the post.
Here is the link to the forum.
www.scannerdanner.com/ForumRetrieve.aspx?ForumID=3226
Thanks!
timothy essex The spark isn't at tdc. Why the question? Do you know of something called ignition advance?
can this be done on a snap on vantage ultra? getting #1 coil signal and do relative compression testing.
yes
Question are you part of the Iatn? Keep up the good work with the videos
How about a vacuum gauge on the intake manifold, wouldn't it also pick up on the leak while the engine was running?
I would like to see this too. Maybe even show the in cylinder compression test waveform with the manifold vacuum waveform. You might be able to show that a bump in manifold pressure corresponds to the peak in compression on that cylinder or something along those lines.
Dennis Rindlisbach Vacuum gauge can reveal a valve seating issue for sure. The key is having a really good and reliable gauge. I have used many gauges over the years and unless you know the gauge is 100% good, there can be to many variables and unreliable readings. But with a good gauge, and exhaust valve seating issue will show up as low vacuum at idle, but pretty steady needle without many fluctuations. An intake valve seating issue allows air to return into the intake manifold causing a sort of "back pressure". This back pressure decreases the vacuum in the manifold, so it shows up on your gauge as a 1-7 in. hg vacuum drop every time the cylinder compresses (needle fluctuation) Vacuum gauge testing is still a valuable and valid test method today, but because of the possibility of variables, there are other tests that are just more reliable.
I have a P0307 briefly pending, then seconds later a P0300 stored on a 2000 5.7 GMC savana only around 2000+ rpm. SES light starts flashing until returning to idle speed. Where should I start? problem is I dont feel a miss. I restart the engine and the pending code goes away until High rpms again. I cleaned the distributor, installed new plugs, tested wires, around 2k ohms. i kind of want to change the cap and rotor and ignition coil, but maybe its a faulty cam sensor confusing the computer?
these engines have distributor cap problems a lot.
Looks like the problem ended up being cracked heads.
Premium fuel only wow that's a bummer. Would have been nice if it was easier fix
When you listen for the noise are you rotating the engine? I dont understand.
I rotated the engine to bring each cylinder that was being tested to its compression stroke (both valves closed)
Does that make sense?
Some fuel and air will leak at compression stroke and amount of exhaust gas returned To the intake may cause lean misfire . That what I am thinking
great tutorial :) will leavec you a replys when i find my cyl 5 misfire :)
How many miles did this occur
is there a reason you used a 2v scale and not 60amp current clamp preset?
yes. I'm trying to read 150-200 amps. It would bury the 60 amp preset scale
Would you still hear that much air leakage in the throttle body or exhaust if it was at the 40% acceptable level?
first I'm not sure 40 percent is considered good. That's just what that gauge said.
And no, you would not hear that much air coming from the throttle body on a good cylinder
as paul said , every engine has different spec.. i use to do this all the time in aircraft engine, and the law allow as 25% leak and yes you could hear it
GOLD!
I know this is an old video, but my first time seeing it. I noticed that when you set your cursors during the firstrelative compression test, the #1 cylinder cursor reading on your scope was 1.44 (144amps), and on #4 the cursor reading was 1.27 (127 amps). Mathematically this is an 11.8% differential between the two cylinders. But when you did the compression check, the #5 cylinder was at 150psi and the#4 was at 125psi for a 16.7% differential. I want to assume that the difference between the compression check and relative compression check is because #5 cylinder, which you didn't measure on the scope, would have been higher then#1 cylinder, or approximately 1.51 (151amps), which would have made a 16.7% difference between high and low cylinders. Is my assumption correct? Also, apart from the fact that you are in a classroom, can I rely upon the fact that there is an 11.8% (16.7%) difference between the high and low cylinder current draw and skip the compression/leak down test or is that a shortcut to trouble? Basically is the mathematical calculations based on current draw reliable enough for a diagnostics? Thanks
It is becoming more and more difficult to answer questions here. I have 80,000 people asking me for help now. So I have created a forum to help you guys better. It is free to join and we can exchange pictures, wiring diagrams and waveforms if needed to help guide you through the process of troubleshooting your vehicle. Thank you so much! Hope to see you there.
Paul Danner (ScannerDanner)
www.scannerdanner.com/forum/post-your-repair-questions-here.html
Paul I agree with you about the interpretation of in cylinder wave form very hard to make the call, a mechanic from other shop call me to diagnoses a ford Econoline the owner of vehicle had this at the ford dealer for this misfire on single cylinder they replace new plugs wires, injector and new coil pack misfire still present ,and they conclude it was mechanical problem they suggested to replace engine, they took it to a independent shop so when I was checking cylinder contribution on scanner only a single cylinder was misfiring under 1500 rpm only I did in cylinder pressure traducer , to compare different cylinder and expansion packet on valves looks different on misfire cylinder then the rest, I make the call bad engine . After they replace the engine same result misfire there same rpm same cylinder i did not what to do any way they call for some else to diagnose and he said it was bad coli pack they replace it and misfire gone . man I feel so bad my big question is how the coil did it it was brand new motor craft and is waste spark how did it occurred at idle and one cylinder only and not companion, why only idle I know the common fail is higher rpm because of demand of kv, I would like to hear from you about this from you how is theory behind it . will account that I am not good with my scope with pressure traducer and ignition system, may be the subject is out but I would appreciate your idea, nice video
Well you assumed a very expensive part was bad with an unreliable test in my opinion. We all make mistakes admitting and learning from them is a characteristic of a good tech. I am really careful with my guilty verdicts. I gotta be sure unless part is very cheap and time to confirm outways heavily. Its an engine bro. Be more careful with your customers money... And your shops as an honest one would eat it. WORD of MOUTH you dig. A damn 4.2 envoy kicked me hard with a damn sneaky coil. Recall for valves leaking too... Go with it?? Nope not sure yet. Running compression test time.. all good all time. No go keep digging.
Never assume a part is good because its new. Never.
How did it fail?? Huh? Cracked it, defective, abused during testing who knows who cares. Why was companion cyl. Ok? Because its output was perhaps. Never assume. Parts DON'T fail the same way all the time. I've seen a many coils that way buddy. Replaced many new parts again. Watch guys sit n wonder what to throw now when parts run out completely ignoing the possibility of installing a bad part and there best guess method actually was accurate. LoL not funny tho. I hate those noobs. Any monkey can replace parts
When I put on a bad part I know it cause I diagnose. I'm a tester not a guess-er. :) you are a human. It was a mistake and bad judgment. Put the fancy scope down and do a real test. Scopes are good but electrical stuff does some strait unearthly impossible weird stuff sometimes. If cylinder miss its valves and piston wouldn't move at same speed as rest. Think about it. Leak down compression off and on.
wai2machine823
history of vehicle for that misfire first was in independent shop they replace plugs and wires same no changes , second the the owner of the vehicle took it to the dealer they said wires and plugs were not genuine they are garbage we have to install from factory they did same misfire, the dealer did second call to owner saying they needed to replace the coil pack and the injector they did and misfire still present genuine parts, they got to the conclusion mechanical problem, third the owner of the vehicle took it to one of my friend shop and she was not asking for diagnostic she had the engine on the back of the truck already she wanted installation, because I have pressure transducer my friend call me to do some testing as a confirmation, I did test all current amp on all injectors and coil pack also I induce a misfire on each cylinder to check if computer was reading accurate remember misfire was under 1500 rpm only , I never scope the secondary side of the coil pack but I spray water around wires and coil pack no physical damage to coil at all , know is easy to know that was the problem because we already know.if the only cylinder was showing me differences on expansion pack was the one had the misfire comparing to the others . If I had started this diagnostic my self I do not know if I had done the call of engine.
Nevertheless superior tutelage Paul..
I don't like that the piston is not at TDC. I think it might be easy for the compressor to push the piston down that way. When the piston is at true TDC, the rod is pretty much aligned straight up and down, and makes it real hard for the piston to move. I use a slick spring-loaded TDC indicator for that from Innovative Products of America, part# 7886, 7880, or 7891. It's a nice luxury.
As long as you hold the wrench firmly this is a perfectly fine way of measuring leakdown. In fact I purposely test leakdown by this method because i believe it to be much better than TDC method since TDC only measure leakdown in fraction of the cylinder while measuring as soon as the valves close measures the entire clylinder and can potentially find compromises in the cylinder wall that would be missed by testing at TDC -e.g. "behind" the piston.
But isn't most of the bore wear at TDC? I suppose if you started at BDC and slowly rotated it to TDC while watching the gage would be ideal. A "moving" leak down test might find issues only occurring in some parts of the bore.
what brand video camera are you using?
+Poochie43124312 a 4+ year old panasonic HD camera (probably a $400 camera at the time)
thanks
Hello Paul
Why you no longer use PICOSCOPE?
next two videos in this series are with the Pico, uploading one of them now.
Went on long drive. All ok.
Next day rough idle. Plugged in OBD.
Have a P0308
Plug is good. Coil is good.
Suspect bad injector.
Yes .... No. ??
My H2 backfires put the pedal to da floor An won't get over 2 RPMs driving wise it won't get to 45mph without backfiring bad? Help
It is becoming more and more difficult to answer questions here. I have 80,000 people asking me for help now. So I have created a forum to help you guys better. It is free to join and we can exchange pictures, wiring diagrams and waveforms if needed to help guide you through the process of troubleshooting your vehicle. Thank you so much! Hope to see you there.
Paul Danner (ScannerDanner)
www.scannerdanner.com/forum/post-your-repair-questions-here.html