That's a great diagnosis. But the problem is how do you get paid? This industry rewards ignorance and stupidity. If I told the service manager that I need 4 or 5 hours diag time (@ $200.00 per hour) he would get another tech to fire the parts cannon. Managers love it, the mark up on parts along with labor to install. Not a care in the world if the problem is solved. I've been in dealers for 48 yrs, and each one is the same.
Diagnostic techs hurt the financial bottom line, that is why we are frowned upon. I think the way this man and many others who are very good at diagnosing and have very good equipment get paid by having a successful you tube channel, and they work for themselves. A half hour video means many hours before editing, how much do you think the Corvette owner was charged? Do you think he was charged for every hour this man spent on it? Not to mention how many hours of studying, research and investment on equipment. With all that said, I am very thank full for this you tube channel and others like it. These guys are very good at what they do, and help many of us furthering our knowledge.
@@rodvan-zeller6360 Guess I should start a utube channel, just so I can get paid to diagnose vehicles. My boss sure isn't go to pay us. We only get paid to install parts. More parts, more pay even if it does not fix the problem. It's the life of flat rate.
Great job! I think the hardest part of analyzing scope patterns is knowing what looks valid and what doesn't look valid, especially if you are in a shop that works on every make and model.
I have learned so much from watching your videos. Thank you so much. I've been a mechanic for about 4 years now, but im starting to want to get more into the deep diagnostic side of things with scopes and reprogram and flashing awsome awsome video blessings and shout out to your boy the camera guy 🙌
The microcontroller clock is usually very robust and not a common exception reset source. There are many other reset sources that are much more likely to cause a ECM strategy reset, for example a faulty power supply or brown out event. It is clear from the scope trace that the ECM reset and batch fired all of the injectors at once, which means they overlap (occur at the same time). There are other indicators of ECM reset. One would be a freeze on real time data from a scan tool. Meaning if a scan tool was set up to get periodic real time data from the ECM it would show that when the car shut down the communication also stopped.
That depends on how long the reset occurs if your scan tool freezes or not. I had a Jeep Commander with the same issue as this one with a stumble and intermittent stall, but it was caused by the failure of the PCM's flyback zeners for the ignition coils. The zeners wouldn't clip off the flyback intermittently and cause the excessive flyback to reset the controller. I had a Autel Elite scan tool connected watching data and it never stopped updating during the events.
This may be tool or network dependent, I have a MaxiSYS MS909. Your Jeep may use a gateway to the PCM (Chrysler was one of the first to use a OBD II gateway), which would be different than the Chevy in the video, which has an OBDII powertrain high speed CAN bus directly available at the DLC. When your jeep reset did you see any data PID dropouts that would indicate the module reset? I am not sure of what type of ignition system your jeep has, but if it is coil on plug with the ignition amps (no smart coils) in the module then the driver is a protected IGBT, with uses an active clamp internal to the device to clip the flyback pulse (at around 430 Volts) at the ignition output. I have never seen a separate flyback Zener used to clip flyback energy. But I have not worked on a Jeep Commander. When the Chevy Corvette ECM resets you will lose both fuel and spark at the same time depending on how the pulse processor enters its reset state. You should be able to see a simultaneous failure caused by a module warm boot (microcontroller reset) in a number of ways. For example monitoring cylinder #1 injector and cylinder #2 ignition pulse (the corvette has smart coils). Both will drop out at about the same time and then reappear at about the same time. You really don't need eight channels in my opinion to spot an ECM reset. The reason the vehicle hiccups is the ECM reset time (boot time) is very fast probably under 100ms, meaning the vehicle may or may not actually stall at idle. @@Discretesignals
In the case of the Chevy Corvette the only bank fired port injection (high impedance) engine family is the L98 C4 (excluding the ZR1) which was superseded by the LT1 in 1992 which had sequential fuel injection using high impedance injectors. With the L98 all injectors fire at once. Although, there are actually two fuel injector output pins one for the left bank and one for the right, both originate from the same power driver within the PCM. If you look at a 1990 Ford Mustang, for example, it had sequential port fuel injection using high impedance injectors. I don't think I have ever seen port peak and hold fuel injection on domestic vehicles, just with throttle body injection, which used two injectors.@kafax123
@@windward2818 It was a 2007 Commander with a 4.7L that I had diagnosed about 10 years ago. It does use a gateway module (the front control module) between the DLC and the network. I honestly don't remember if any PIDs were dropping out, but communications never was lost. I still have the scope captures and its coils' flyback was over 400 volts. If my scope wasn't attenuated, it would have blown the front end right off it. I figured out it was resetting or halting because the NGC was tripping the ASD relay right after a coil kickback event. That is when I focused on coil primaries. It uses two wire ignition coils and the coil drivers and suppression diodes are in the NGC. To be honest I am not sure how the spikes are clamped inside the NGC, so I'm guessing a zener or some form of suppression is used. I didn't realize the kick back voltage was abnormal until after all other possibilities were exhausted and I replaced the NGC. I even replaced all coils and plugs with dealer parts before condemning the NGC because for sure I thought it was an inductive kick issue. When I replaced the NGC it fixed the problem. I rescoped and found that normal flyback was suppressed to around 280 volts. That is why interpretting waveforms is difficult if you don't know what is good and what is bad. Interpreting comes with experience and sometimes that can get expensive or time consuming unless you have a known good vehicle to compare to. The reset time was 250 microsecs. I agree, you surely don't need 8 channels to see a reset. I wonder if this year Vette uses a batch fire strategy during first start and goes straight to sequential firing? Good luck finding that in service data. By the way, happy holidays.
That is outstanding troubleshooting. Narrow down the problem and isolate the issue instead of shotgunning. I did much of the same when diagnosing networking issues.
What you're explaining here is 100% spot on what is happening to my 2005 Dodge Ram 1500. I don't have a scope. I've been thinking for awhile, it's my PCM. I think I'm going to just take a shot in the dark. And change it. It runs for 5 mins-10 mins and shuts off. Happens while driving as well. It will buck and keep going. Gets slightly better as it warms up. I've also noticed it charges over normal. Which is not normal. Changed crank sensor, plugs, wires, coils, checked everything. Still stalls just like that corvette. I think the voltage regulators in the PCM is going bad. My PCM is around $300. Think I'm going to change it.
Video of the year, good video to wrap up the year with. Thanks for all details and tips. BTW, the camera man, AKA your son. does an outstanding job filming and zooming in so close to show us everything. Thanks both.
I’m 24 minutes in and I’m getting impatient 😁 but I shouldn’t because you are showing us your diagnosis process of excluding one component after another instead of just showing the cause of the issue. This is much more informational and valuable and it’s why I like watching your videos so much! Thanks! Happy holidays!
Thank you for actually diagnosing the issue and proving the problem. Not many technicians do! I’ve been watching a lot of Bernie Thompson’s videos and will now be watching yours, too.
29:06 I‘d love to know that saying! 😁 30:50 I’m here for the camera work! 👍😁 33:38 Yes, you definitely need a scope for the less obvious faults. You also need capable technicians who know and understand how to use them.
The importance of using an oscilloscope is vital - as demonstrated here fully. Just today I got off the phone with a potential employer - Honda dealer , their position on scopes is “We haven’t used those for years, we use scan tool data” - I thanked them for their time. Keep up the good work fellas!!
Had a similar scenario on a OBD 1 TPI 7730 setup.... Gm 350CI engine, Gm Fastburn heads and LT4 Hotcam, GM sold it under the "ZZ430" crate engine... Once the car was being tuned properly and the AFR ratios being dialed in via VE Tables to properly reflect the modifications made, it suddenly out of nowhere developed this rare "TIP IN" dying out situation like the Vette in this video.... You could start it and leave it in P/N and rev it, or idle all day long until it drained the gas tank dry..... But soon as it went in gear, 50% of the time it would sputtered out...... Worse part is it wouldn't throw a code that stayed due to engine quitting each time having to restart... Would start back perfect and idle every time! It finally took doing a data-log and watching it via playback to see what was happening... Code 33 would flash for a split second (CODE 33 = HIGH MAP) reading and the engine would go crazy when it would happen even though it was just a split second event. Once MAX MAP was set from (67 KPA to 80 KPA ) due to overlap of cam, (PROBLEM SOLVED)! Never had that issue again.,.. So whenever you install a cam with overlap or that can cause less vacuum at certain spots, be sure the settings in the ECM are changed to compensate it. But none the less, it took a logger like this to find it... Anyone can be a "PARTS CHANGER", and keep throwing parts at something, then still have the issue... A real "MECHANIC" properly diagnoses the problem, figures it out, then fixes it for good or tries to..
What a great video, showing how you can use a scope, with a step by step diag plan, to exclude or confirm each component that could cause the issue. Very informative! Unfortunately my Hantek 8 ch scope doesn't have anywhere near the same specs & features as your AES wave scope. But I don't actually wrench for a living, so it fits my needs. I'm an internal service "advisor", but I have a lot of old school experience & doing all I can to learn the new tech, so I can try to help out my young, inexperienced guys.
I can say for sure, if this car was in my bay I’d be holding my breath until the repair was made. Because these types of problems, there’s no one single test that tells you what the main issue is. Good job
Highly unlikely crank or cam sensor could reset the ecu, both low power 5 or 12 volt reference, hall effect (magnetic) - so very little ability to spike anything. 3 common faults with electronics especially at this age are: Faulty capacitor(s) (not usually an issue in automotive electronics) , weak component (often from static damage - which can occur early in life but show up much later) or most likely a dry solder joint. Solder is basically crystalline, oxidation forms along the lattice structure causing bad joints - or just badly soldered to start with. Temperature cycles put stress on the solder joints over time. Holden VN V6s had common failures of ECMs at 160K Kms/100K miles. Resolder was an easy fix. Worth a visual inspection of ECU connectors and board - and using a soldering iron (proper electronics one) on and any (or just all) even slightly dodgy looking joins.
I had a 2007 with 39k come in my shop with this problem. Lucky it had a code complaining about a internal module failure. I replaced the battery and module. Nice work with that scope!
I've been dealing with a similar problem with a Pontiac 1996. But this one is double firing injectors. Cam and Crack signals good. Pwr grd good. We called it a pcm. Customer is waiting till after the holidays. So hopefully that is it. But you are right like barnie said need more channels in the scope. Specially me with a 4 channel.
The best channel for transparency and diagnostics. Anyone can change a part but proper diagnosis ability wins the race. Excellent channel! I`ll recommend it to all my moto people.
This guy is a great teacher & he can really read a scope. I haven't seen GM put the PCM in the wheel well in a really long time. Usually there are in the engine bay. Reminds me of the old days when they had cracked solder joints on the PCM. The test was to tap it lightly to get it to work again Then you knew it was bad.. Great video.
Great job , I agree with your diagnosis procedure / process 100 percent . I watch Ivan, scanner danner, Eric o Bernie ect.. all work logically and decisively . I understand this part , i have been doing this type of work in a different industry for many years , automotive repair as a hobby. What i would like to know is how do you charge for a job like this? Thousands of dollars worth of test gear , hundreds tied up in software subscriptions for wiring diagrams and specs and hours and hours of diag time. Thanks for any incite
Most shops bill their hourly rate for diagnostics. I coordinate and communicate service for a living and diagnostic communication about complexity and cost is one of the more difficult parts of the job. Give or take your area that hourly rate for a high quality shop capable of this level is nearing $200 an hour. At the end of the day diagnostics are not normally where a shop makes money. A lot of diagnostic time is given away for a variety of reasons and even if you bill for all your diagnostic time you could have been knocking out three brake/fluid services making more money with easier work. There are exceptions to this but, as a whole, shops are just looking to cover their time in it and move on to solving the problem and selling more work.
Been a one man band shop owner for 40 yrs. Hear me out haters, so you have at least 4-6 hrs. proving a bad pcm, then putting on a junkyard unit? I say check powers, grounds and load the cannon. Most times you have pattern failures that will save a lot of time. Yeah prove the crank and cam signals, maybe replace them with factory parts, then go for the pcm. Of coarse you should keep customer in the loop! In my shop I can't afford to putz around for a day proving a bad pcm. On normal vehicles they are not that much with programming vs. time spent proving it. Just my humble opinion. Good video though, nice shop too!❤
Just did this exact thing and I buy all my tools as I need them. Best part is when I'm done at the end of the day all my tools can be used for my hobbies too. Same thing with learning: just do it gradually over time
Great video! The one thing about those scopes is that there isn't any channel labels. I would get confused running 8 channels without labels to remember whats what when I went back to look at the captures.
In some of our previous videos we show how we use small dry erase boards to keep track of leads. Definitely can get confusing if you don't write them down.
Wow. Amazing to see how a multi decade technician explains how he thinks. Diagnostics can lead you into a rabbit hole no doubt about that. What caused the ECU to fail?
just sitting here thinking of other tests you could do to to eliminate what is causing a reset condition. Could you run a bi directional test, such as commanding the purge valve duty cycle, lets say 50%, with the KOEO. That's as long as the bidirectional test doesn't have a timer. Watch the purge valve signal at the valve itself using your scope. If a reset occurs, you should see the purge valve command signal drop off. If it drops out, you just eliminated coil spikes, excessive AC ripple, CMP/CKP glitches, etc.
i had a similar issue on the A/C module of one of my cars ( Alfa romeo 146 td 1996) the only electronic module it has, 15 minutes running and then turn off hahaha. There i learned to read schmatics... thanks Good video !!
Good job Sherwood. I remember back in the OBD1 days with GM ECMs and their failure prone issues, we would give the ECM a few light raps with a screwdriver handle and get them to cause stumbling/stalling issues. Wonder if this might have helped identify the PCM as the issue?
Had that on a 1989 Regal with a reman Delco unit . Get it hot and it shut off . Spank the heck out of the ECM and it stumbled and shut off . IDIOT shop has put complete exhaust , CAT , coils and plugs !
The old "Tap Test". Did it many times. Doesn't really work on modern modules. The reason it worked back in the day was the problem in the module was usually a connection issue (solder joint). If I knew then what I know now we could have probably fixed them rather then replace them. Except for the GMs that the board would crack.
Ats is a good scope but i dont like how you have to buy everything ats to work with this scope. From pressure transducers to amp clamps and secondary ignition. Pico will work with any custom probes. Otherwise its a great scope
Sounds like the mosfet drive circuit took a hit during the jump start that causes the mosfets to all close circuit at once. MP detected this and shuts down. Had a Nissan doing the same thing but only on one injector.
Great video, nice scope. Keep in mind the Fast Fourier Transform (FFT) analysis is looking at the frequency content and relative power contained in each frequency bin of the time based signal out of the sensor.The bottom axis is frequency in HZ many those anomalies are digital signal processing phenomena or electrical noise. Probably more useful just to look at the time based signals out of transducer, and overlay it on top of a good trace of the cam sensor. The vertical axis is only useful for relative signal power and comparison purposes. Especially if your vertical axis is displayed in decibels. You really can’t scrutinize the FFT plot unless you have a baseline plot of a normal functioning sensor response. So if you see new frequencies at high amplitudes that weren’t present before, you know something is wrong
THANK YOU SO MUCH FOR CALLING naturally aspirated A engine, I ask others what are you going to call your tesla a engine? No they will call it a drive MOTOR they won't call it a engine, so thank-you fir calling it a engine, sry for rant. Grt video, and when you are as professional as your shop is, always grt to hear you refer to people as your client versus customer, we're not at autozone lol
I actually scoped the crank signal, cam signal, coil, and a couple of injectors on my first capture. That's my normal process for a shutting off problem. I want to see what i lost then make a decision based on that data.
We send those to the dealership and fix it after they diagnose it for us! That way customers can't blame us and we don't have to buy $1,500+ Scanners and Accessories!
Love your videos. I have the escope and it's really nice that someone besides Bernie uses it to make diag videos. Those that have a pico this can be don't using the math channel feature on pico. But it's way way way easier on Bernies scope. The escope has so many more features that are way more user friendly. I have used both and escope wins for sure.
10:46 I had a Super Trooper moment! Mac: "What about that little fella?" Thorn: "OH, that little guy, I wouldn't worry about that little guy". Man I enjoyed that movie! 😂
if the ecm is bad, it would probably wouldnt throw a code, since it bad it wouldnt self diagnose an issue with it self, im glad the ecm did not blame something else and initiate a rabbit hole run
I yelled at you the whole video. It's the CKP, it's an intermittent shorted injector. It's a PCM. You took the right steps, and I have learned something. Thanks brother. P.S. take it easy on the cameraman. He can make you look good, or he can make you look bad. Great video.
Never fails when you have an issue but as soon as you tell someone about it it will make a liar out of you happened to me a few times it drives you crazy
I have question its this, on chrysler jeep vehicles, that add aftermarket headlights, tipm always has codes for these, what is tipm looking at or for that causes codes, when headlights wrk, my guess is some sort of power and or resistance change it sees, but see all the time when scanning, says headlight and if park light circuit codes if Led bulbs used, can you cure this after using aftermarket lights, not huge deal but didn't know, what tipm uses to determine u changed bulbs, MERRY CHRISTMAS
If I didn't have a scope and like you said no codes could I use a break out box to get to the right direction of the problem ?? Thanks again you guys are 10 stars ! keep the videos coming
You're going to get a ripple but you may have downward spikes. If you do have spikes the the diode trio is bad. Most people just replace the alternator, which will fix that problem. Hth.
29:00 I just want to know what you couldn’t say on TH-cam. I’ve been working on computers forever and I agree, computers almost always fail due to bad maintenance or an associated gear failure.
Ever try just reprogram the module? I have had module issues multiple times on equipment. Combine, tractor, sprayer, loader, different equipment. Reprogrammed it and fixed the problem. Software went goofy. Every time the dealer or tech told it won't fix it. Never had one when the issue came back when a reprogram fix it. Doesn't take long and can often cost only time. Just a thought.
Folks that just hang parts, before a shop as you gets to look at it, they spend all there money and leave none sometimes for the real answer, almost like copying off my paper in school, cuz they don't want to put the time in, and they get my d or f, thanks guys. MERRY CHRISTMAS FROM ADVANCED ALIGNMENT, Princeton. ILL.
That's a great diagnosis. But the problem is how do you get paid? This industry rewards ignorance and stupidity. If I told the service manager that I need 4 or 5 hours diag time (@ $200.00 per hour) he would get another tech to fire the parts cannon. Managers love it, the mark up on parts along with labor to install. Not a care in the world if the problem is solved. I've been in dealers for 48 yrs, and each one is the same.
Diagnostic techs hurt the financial bottom line, that is why we are frowned upon.
I think the way this man and many others who are very good at diagnosing and have very good equipment get paid by having a successful you tube channel, and they work for themselves.
A half hour video means many hours before editing, how much do you think the Corvette owner was charged?
Do you think he was charged for every hour this man spent on it? Not to mention how many hours of studying, research and investment on equipment.
With all that said, I am very thank full for this you tube channel and others like it.
These guys are very good at what they do, and help many of us furthering our knowledge.
@@rodvan-zeller6360 Guess I should start a utube channel, just so I can get paid to diagnose vehicles. My boss sure isn't go to pay us. We only get paid to install parts. More parts, more pay even if it does not fix the problem. It's the life of flat rate.
@@scrappy7571 Flat rape.
Most places only pay for manual labor, not brain labor.
Replace dont chase
@@rodvan-zeller6360
As with most of us who do it daily, we usually bill 50% of our diagnosis time to be fair!
Lots of distractions etc
How squeeze years of knowledge, experience and butt kickings into a 35 minute video!
Great job! I think the hardest part of analyzing scope patterns is knowing what looks valid and what doesn't look valid, especially if you are in a shop that works on every make and model.
That scope is incredible. My dream tool. Great video. You guys are next level. Professor is an incredible teacher. And shout out to the camera man. 😂👍
There are quite affordable automotive 8 channel scopes available. From $€ 125
Who make 8-channel scopes & what are the pros & cons of each?
@@gfbemc0256 this scope is an ATS eScope elite8. It’s top of the line but it’s expensive.
@@Conservator.Like which brands?
@@doomkid02 just search “8 channel scope” to find brands and prices.
I have learned so much from watching your videos. Thank you so much. I've been a mechanic for about 4 years now, but im starting to want to get more into the deep diagnostic side of things with scopes and reprogram and flashing awsome awsome video blessings and shout out to your boy the camera guy 🙌
The microcontroller clock is usually very robust and not a common exception reset source. There are many other reset sources that are much more likely to cause a ECM strategy reset, for example a faulty power supply or brown out event. It is clear from the scope trace that the ECM reset and batch fired all of the injectors at once, which means they overlap (occur at the same time). There are other indicators of ECM reset. One would be a freeze on real time data from a scan tool. Meaning if a scan tool was set up to get periodic real time data from the ECM it would show that when the car shut down the communication also stopped.
That depends on how long the reset occurs if your scan tool freezes or not. I had a Jeep Commander with the same issue as this one with a stumble and intermittent stall, but it was caused by the failure of the PCM's flyback zeners for the ignition coils. The zeners wouldn't clip off the flyback intermittently and cause the excessive flyback to reset the controller. I had a Autel Elite scan tool connected watching data and it never stopped updating during the events.
This may be tool or network dependent, I have a MaxiSYS MS909. Your Jeep may use a gateway to the PCM (Chrysler was one of the first to use a OBD II gateway), which would be different than the Chevy in the video, which has an OBDII powertrain high speed CAN bus directly available at the DLC.
When your jeep reset did you see any data PID dropouts that would indicate the module reset? I am not sure of what type of ignition system your jeep has, but if it is coil on plug with the ignition amps (no smart coils) in the module then the driver is a protected IGBT, with uses an active clamp internal to the device to clip the flyback pulse (at around 430 Volts) at the ignition output. I have never seen a separate flyback Zener used to clip flyback energy. But I have not worked on a Jeep Commander.
When the Chevy Corvette ECM resets you will lose both fuel and spark at the same time depending on how the pulse processor enters its reset state. You should be able to see a simultaneous failure caused by a module warm boot (microcontroller reset) in a number of ways. For example monitoring cylinder #1 injector and cylinder #2 ignition pulse (the corvette has smart coils). Both will drop out at about the same time and then reappear at about the same time. You really don't need eight channels in my opinion to spot an ECM reset. The reason the vehicle hiccups is the ECM reset time (boot time) is very fast probably under 100ms, meaning the vehicle may or may not actually stall at idle. @@Discretesignals
In the case of the Chevy Corvette the only bank fired port injection (high impedance) engine family is the L98 C4 (excluding the ZR1) which was superseded by the LT1 in 1992 which had sequential fuel injection using high impedance injectors. With the L98 all injectors fire at once. Although, there are actually two fuel injector output pins one for the left bank and one for the right, both originate from the same power driver within the PCM. If you look at a 1990 Ford Mustang, for example, it had sequential port fuel injection using high impedance injectors. I don't think I have ever seen port peak and hold fuel injection on domestic vehicles, just with throttle body injection, which used two injectors.@kafax123
How much time in testing did you have for an issue like this?
@@windward2818 It was a 2007 Commander with a 4.7L that I had diagnosed about 10 years ago. It does use a gateway module (the front control module) between the DLC and the network. I honestly don't remember if any PIDs were dropping out, but communications never was lost. I still have the scope captures and its coils' flyback was over 400 volts. If my scope wasn't attenuated, it would have blown the front end right off it. I figured out it was resetting or halting because the NGC was tripping the ASD relay right after a coil kickback event. That is when I focused on coil primaries. It uses two wire ignition coils and the coil drivers and suppression diodes are in the NGC. To be honest I am not sure how the spikes are clamped inside the NGC, so I'm guessing a zener or some form of suppression is used.
I didn't realize the kick back voltage was abnormal until after all other possibilities were exhausted and I replaced the NGC. I even replaced all coils and plugs with dealer parts before condemning the NGC because for sure I thought it was an inductive kick issue. When I replaced the NGC it fixed the problem. I rescoped and found that normal flyback was suppressed to around 280 volts. That is why interpretting waveforms is difficult if you don't know what is good and what is bad. Interpreting comes with experience and sometimes that can get expensive or time consuming unless you have a known good vehicle to compare to. The reset time was 250 microsecs.
I agree, you surely don't need 8 channels to see a reset. I wonder if this year Vette uses a batch fire strategy during first start and goes straight to sequential firing? Good luck finding that in service data. By the way, happy holidays.
As usual a superb presentation with a step-by-step elimination of all possible causes , enjoy watching and learning even at my age 😊
That is outstanding troubleshooting. Narrow down the problem and isolate the issue instead of shotgunning. I did much of the same when diagnosing networking issues.
What you're explaining here is 100% spot on what is happening to my 2005 Dodge Ram 1500. I don't have a scope. I've been thinking for awhile, it's my PCM. I think I'm going to just take a shot in the dark. And change it. It runs for 5 mins-10 mins and shuts off. Happens while driving as well. It will buck and keep going. Gets slightly better as it warms up. I've also noticed it charges over normal. Which is not normal. Changed crank sensor, plugs, wires, coils, checked everything. Still stalls just like that corvette. I think the voltage regulators in the PCM is going bad. My PCM is around $300. Think I'm going to change it.
Video of the year, good video to wrap up the year with. Thanks for all details and tips. BTW, the camera man, AKA your son. does an outstanding job filming and zooming in so close to show us everything. Thanks both.
I’m 24 minutes in and I’m getting impatient 😁 but I shouldn’t because you are showing us your diagnosis process of excluding one component after another instead of just showing the cause of the issue.
This is much more informational and valuable and it’s why I like watching your videos so much! Thanks!
Happy holidays!
That's a hard one for a lot of top notch techs.! Great find.! Congratulations..!
Thank you for actually diagnosing the issue and proving the problem. Not many technicians do! I’ve been watching a lot of Bernie Thompson’s videos and will now be watching yours, too.
29:06 I‘d love to know that saying! 😁
30:50 I’m here for the camera work! 👍😁
33:38 Yes, you definitely need a scope for the less obvious faults. You also need capable technicians who know and understand how to use them.
The importance of using an oscilloscope is vital - as demonstrated here fully. Just today I got off the phone with a potential employer - Honda dealer , their position on scopes is “We haven’t used those for years, we use scan tool data” - I thanked them for their time. Keep up the good work fellas!!
Dealers don’t diagnose cars. They do the parts cannon approach to repair
You covered alot great diagnosis guys . Alot of shops I remember didnt have scopes due to the cost.
Had a similar scenario on a OBD 1 TPI 7730 setup....
Gm 350CI engine, Gm Fastburn heads and LT4 Hotcam, GM sold it under the "ZZ430" crate engine...
Once the car was being tuned properly and the AFR ratios being dialed in via VE Tables to properly reflect the modifications made, it suddenly out of nowhere developed this rare "TIP IN" dying out situation like the Vette in this video.... You could start it and leave it in P/N and rev it, or idle all day long until it drained the gas tank dry..... But soon as it went in gear, 50% of the time it would sputtered out...... Worse part is it wouldn't throw a code that stayed due to engine quitting each time having to restart... Would start back perfect and idle every time!
It finally took doing a data-log and watching it via playback to see what was happening... Code 33 would flash for a split second (CODE 33 = HIGH MAP) reading and the engine would go crazy when it would happen even though it was just a split second event.
Once MAX MAP was set from (67 KPA to 80 KPA ) due to overlap of cam, (PROBLEM SOLVED)! Never had that issue again.,..
So whenever you install a cam with overlap or that can cause less vacuum at certain spots, be sure the settings in the ECM are changed to compensate it.
But none the less, it took a logger like this to find it...
Anyone can be a "PARTS CHANGER", and keep throwing parts at something, then still have the issue... A real "MECHANIC" properly diagnoses the problem, figures it out, then fixes it for good or tries to..
What a great video, showing how you can use a scope, with a step by step diag plan, to exclude or confirm each component that could cause the issue. Very informative! Unfortunately my Hantek 8 ch scope doesn't have anywhere near the same specs & features as your AES wave scope. But I don't actually wrench for a living, so it fits my needs. I'm an internal service "advisor", but I have a lot of old school experience & doing all I can to learn the new tech, so I can try to help out my young, inexperienced guys.
I can say for sure, if this car was in my bay I’d be holding my breath until the repair was made. Because these types of problems, there’s no one single test that tells you what the main issue is. Good job
Highly unlikely crank or cam sensor could reset the ecu, both low power 5 or 12 volt reference, hall effect (magnetic) - so very little ability to spike anything. 3 common faults with electronics especially at this age are: Faulty capacitor(s) (not usually an issue in automotive electronics) , weak component (often from static damage - which can occur early in life but show up much later) or most likely a dry solder joint. Solder is basically crystalline, oxidation forms along the lattice structure causing bad joints - or just badly soldered to start with. Temperature cycles put stress on the solder joints over time. Holden VN V6s had common failures of ECMs at 160K Kms/100K miles. Resolder was an easy fix. Worth a visual inspection of ECU connectors and board - and using a soldering iron (proper electronics one) on and any (or just all) even slightly dodgy looking joins.
I had a 2007 with 39k come in my shop with this problem. Lucky it had a code complaining about a internal module failure. I replaced the battery and module. Nice work with that scope!
I love the Hz plot feature... Great video
Glad you were able to diagnose the problem. Great work great video.
Good call,I also check 5v reference when having a ecm reset
Great job! The scope doesn’t lie.
Thanks Sherwood for this valuable information on diagnostic every aspect of this vehicle.
I've been dealing with a similar problem with a Pontiac 1996. But this one is double firing injectors. Cam and Crack signals good. Pwr grd good. We called it a pcm. Customer is waiting till after the holidays. So hopefully that is it. But you are right like barnie said need more channels in the scope. Specially me with a 4 channel.
The best channel for transparency and diagnostics. Anyone can change a part but proper diagnosis ability wins the race. Excellent channel! I`ll recommend it to all my moto people.
ATS escope 8 channel is On my 2024 wish list for sure
Bernie Thompson yourself in 2024. If you could get it from G. It would cost you less than $6,000. Happy Holidays seasons
Great stuff Sherwood. Need more like you.
Another great video with absolutely great info
I love these scope videos. Keep em coming! I also like any video showing the shop dog!
This guy is a great teacher & he can really read a scope. I haven't seen GM put the PCM in the wheel well in a really long time. Usually there are in the engine bay. Reminds me of the old days when they had cracked solder joints on the PCM. The test was to tap it lightly to get it to work again Then you knew it was bad.. Great video.
Another great ONE !! Thanks to the Camera Dude : )
That escope is amazing. Got to use it for a week at the shop. Need to invest and buy one
Great job , I agree with your diagnosis procedure / process 100 percent .
I watch Ivan, scanner danner, Eric o Bernie ect.. all work logically and decisively . I understand this part , i have been doing this type of work in a different industry for many years , automotive repair as a hobby. What i would like to know is how do you charge for a job like this? Thousands of dollars worth of test gear , hundreds tied up in software subscriptions for wiring diagrams and specs and hours and hours of diag time. Thanks for any incite
Most shops bill their hourly rate for diagnostics. I coordinate and communicate service for a living and diagnostic communication about complexity and cost is one of the more difficult parts of the job. Give or take your area that hourly rate for a high quality shop capable of this level is nearing $200 an hour.
At the end of the day diagnostics are not normally where a shop makes money. A lot of diagnostic time is given away for a variety of reasons and even if you bill for all your diagnostic time you could have been knocking out three brake/fluid services making more money with easier work. There are exceptions to this but, as a whole, shops are just looking to cover their time in it and move on to solving the problem and selling more work.
Been a one man band shop owner for 40 yrs. Hear me out haters, so you have at least 4-6 hrs. proving a bad pcm, then putting on a junkyard unit? I say check powers, grounds and load the cannon. Most times you have pattern failures that will save a lot of time. Yeah prove the crank and cam signals, maybe replace them with factory parts, then go for the pcm. Of coarse you should keep customer in the loop! In my shop I can't afford to putz around for a day proving a bad pcm. On normal vehicles they are not that much with programming vs. time spent proving it. Just my humble opinion. Good video though, nice shop too!❤
Just did this exact thing and I buy all my tools as I need them. Best part is when I'm done at the end of the day all my tools can be used for my hobbies too. Same thing with learning: just do it gradually over time
where you getting your service info from?@@omnicode
Thank you guys for filming and sharing this!
I remember the old guys who had the old analog scopes and parts books thicker than 4 telephone books!
Learned fifty years ago the value of a. Ancient scope when cook guy captured my car I. A garage avd said figure it out . I did and it was great
Great video! The one thing about those scopes is that there isn't any channel labels. I would get confused running 8 channels without labels to remember whats what when I went back to look at the captures.
In some of our previous videos we show how we use small dry erase boards to keep track of leads. Definitely can get confusing if you don't write them down.
Wow. Amazing to see how a multi decade technician explains how he thinks. Diagnostics can lead you into a rabbit hole no doubt about that. What caused the ECU to fail?
The client stated he had had a lot of battery problems and had jump-started it several times. We believe this is what damaged the ecm.👍
Very interesting, these type problems is what separate's the men from the boys as far as mechanics are concerned.
Scopes are one of my favorite tools to use. But I was never brave enough to do my own shop....
Other problem was places down playing the diags. Its like ummm no youre not waving the diag.
Nice shout out for Bernie! Nice job!
Great diagnostic tutorial.
Thank you AND the camera guy for another great video! I hope you and your families have a wonderful Christmas!
That's really helpful technology right there
just sitting here thinking of other tests you could do to to eliminate what is causing a reset condition. Could you run a bi directional test, such as commanding the purge valve duty cycle, lets say 50%, with the KOEO. That's as long as the bidirectional test doesn't have a timer. Watch the purge valve signal at the valve itself using your scope. If a reset occurs, you should see the purge valve command signal drop off. If it drops out, you just eliminated coil spikes, excessive AC ripple, CMP/CKP glitches, etc.
Great diag for sure!! You’re going to have to take over for Bernie if/when he retires!
Haha, I don't think I could ever be at his level. But thanks!!
Great video and explanation- I would t ever own anything to that caliber but it is great to see.
i had a similar issue on the A/C module of one of my cars ( Alfa romeo 146 td 1996) the only electronic module it has, 15 minutes running and then turn off hahaha. There i learned to read schmatics... thanks Good video !!
Good job Sherwood. I remember back in the OBD1 days with GM ECMs and their failure prone issues, we would give the ECM a few light raps with a screwdriver handle and get them to cause stumbling/stalling issues. Wonder if this might have helped identify the PCM as the issue?
Had that on a 1989 Regal with a reman Delco unit . Get it hot and it shut off . Spank the heck out of the ECM and it stumbled and shut off . IDIOT shop has put complete exhaust , CAT , coils and plugs !
The old "Tap Test". Did it many times. Doesn't really work on modern modules. The reason it worked back in the day was the problem in the module was usually a connection issue (solder joint). If I knew then what I know now we could have probably fixed them rather then replace them. Except for the GMs that the board would crack.
Excellent skills
Ats is a good scope but i dont like how you have to buy everything ats to work with this scope. From pressure transducers to amp clamps and secondary ignition. Pico will work with any custom probes. Otherwise its a great scope
Sounds like the mosfet drive circuit took a hit during the jump start that causes the mosfets to all close circuit at once. MP detected this and shuts down.
Had a Nissan doing the same thing but only on one injector.
Great video shout out to your son good work.thanks for sharing
Great video, nice scope. Keep in mind the Fast Fourier Transform (FFT) analysis is looking at the frequency content and relative power contained in each frequency bin of the time based signal out of the sensor.The bottom axis is frequency in HZ many those anomalies are digital signal processing phenomena or electrical noise. Probably more useful just to look at the time based signals out of transducer, and overlay it on top of a good trace of the cam sensor. The vertical axis is only useful for relative signal power and comparison purposes. Especially if your vertical axis is displayed in decibels. You really can’t scrutinize the FFT plot unless you have a baseline plot of a normal functioning sensor response. So if you see new frequencies at high amplitudes that weren’t present before, you know something is wrong
Great work 🫡
THANK YOU SO MUCH FOR CALLING naturally aspirated A engine, I ask others what are you going to call your tesla a engine? No they will call it a drive MOTOR they won't call it a engine, so thank-you fir calling it a engine, sry for rant. Grt video, and when you are as professional as your shop is, always grt to hear you refer to people as your client versus customer, we're not at autozone lol
What made you decide to scope all 8 injectors first? Thanks for sharing!
I actually scoped the crank signal, cam signal, coil, and a couple of injectors on my first capture. That's my normal process for a shutting off problem. I want to see what i lost then make a decision based on that data.
We send those to the dealership and fix it after they diagnose it for us! That way customers can't blame us and we don't have to buy $1,500+ Scanners and Accessories!
Most dealer techs would not be able to diagnose a problem like this
Great Diagnostics. That's what people pay for.
Very informative. Really good video. Was able to learn a lot. Thank you guys.
Happy Christmas, Royalty Auto Service
👍
From Nick Ayivor from London England UK 🇬🇧 ⏰️ 20:24pm Good Evening
Thank you 📷 man, your son
That was great 👍🏼 ! Thanks
Love your videos. I have the escope and it's really nice that someone besides Bernie uses it to make diag videos. Those that have a pico this can be don't using the math channel feature on pico. But it's way way way easier on Bernies scope. The escope has so many more features that are way more user friendly. I have used both and escope wins for sure.
10:46 I had a Super Trooper moment!
Mac: "What about that little fella?"
Thorn: "OH, that little guy, I wouldn't worry about that little guy".
Man I enjoyed that movie! 😂
if the ecm is bad, it would probably wouldnt throw a code, since it bad it wouldnt self diagnose an issue with it self, im glad the ecm did not blame something else and initiate a rabbit hole run
Intermittent faults are the most difficult to diagnose.
How many hours of diagnoses did you charge versus how many hours you have into it?
Great one. Thanks for sharing 🙏
I yelled at you the whole video. It's the CKP, it's an intermittent shorted injector. It's a PCM. You took the right steps, and I have learned something. Thanks brother. P.S. take it easy on the cameraman. He can make you look good, or he can make you look bad. Great video.
Did it get repaired? Do not see a follow up video? This stuff is well over my head but I enjoy watching and learning.
Never fails when you have an issue but as soon as you tell someone about it it will make a liar out of you happened to me a few times it drives you crazy
Great video, I am surprised there was no code in failure records.
I have question its this, on chrysler jeep vehicles, that add aftermarket headlights, tipm always has codes for these, what is tipm looking at or for that causes codes, when headlights wrk, my guess is some sort of power and or resistance change it sees, but see all the time when scanning, says headlight and if park light circuit codes if Led bulbs used, can you cure this after using aftermarket lights, not huge deal but didn't know, what tipm uses to determine u changed bulbs, MERRY CHRISTMAS
If I didn't have a scope and like you said no codes could I use a break out box to get to the right direction of the problem ?? Thanks again you guys are 10 stars ! keep the videos coming
I don't see any way this could be diagnosed with a definitive answer without a scope.
More like this please
Sure do appreciate all that you do it's impressive thanks
Agreed ! 100 % !!
Good show.
Beautiful car.
Thank you, camera man
Thats awesome that you can call Bernie for advice, even the best techs need help sometimes. But who does Bernie call? Probably God.
What if In a case were you do an AC ripple test on an Alternator and you have no ripple effect. What does this translates into. Nice job here
You're going to get a ripple but you may have downward spikes. If you do have spikes the the diode trio is bad. Most people just replace the alternator, which will fix that problem. Hth.
I just realized y'all were in the Kings Bay area. I might have to bring something down there if I find myself struggling to diagnose it...
29:00 I just want to know what you couldn’t say on TH-cam. I’ve been working on computers forever and I agree, computers almost always fail due to bad maintenance or an associated gear failure.
4 channel scope would work. Been a nice capture of a current ramp of the injectors when they all fired at once.
love all the information and great find just want to know if you able to find this without a scope
Should set a code, but what about a 5V sensor pulling 5V reference to ground.
That does happen but it wouldn't reset the clock.
Ahh, ok. In certain Chrysler products the AC pressure transducer would short out and cause a stall.@@theroyaltyautoservice
Well, I'm just gonna change the module and see if it helps
Now if I can just get my shop to buy the ATS scope and tablet combo.
Ever try just reprogram the module? I have had module issues multiple times on equipment. Combine, tractor, sprayer, loader, different equipment. Reprogrammed it and fixed the problem. Software went goofy. Every time the dealer or tech told it won't fix it. Never had one when the issue came back when a reprogram fix it. Doesn't take long and can often cost only time. Just a thought.
Great idea to reprogram
The proper term your looking for is "VOLTAGE SPIKES"
I saw the problem right away. The car is not a 1993 Celica or other old Toyota. No charge for my diagnostic service.
Do you work for free?? Good for you!!
Hi u had a/c videos u said u will make more didnt see them
They are coming.
Legend
Camera guys rules
Camera guy!
How do you charge the customer for all that time you spent on it
Folks that just hang parts, before a shop as you gets to look at it, they spend all there money and leave none sometimes for the real answer, almost like copying off my paper in school, cuz they don't want to put the time in, and they get my d or f, thanks guys. MERRY CHRISTMAS FROM ADVANCED ALIGNMENT, Princeton. ILL.