Crank No Start That No One Could Fix SBQM Free Video!

2009 GMC Sierra with a crank no start that several techs unable to diagnose but they are sure it's a Crank sensor signalling issue. Looks like they are right.
This video will be available for a limited time here just so the shop can watch the video on this channel- otherwise it will be on my paid content channel at www.schrodingersboxqm.com (Schrodingers Box Quantum Mekanix).
Download our free book while you are there!!
The Diagnosis and Understanding: Ignition Systems video is here: schrodingersboxqm.com/diagnos...

[@erikkirby1]

as a 25 years auto tech i can tell you we learn everyday! if you are willing to!!!

[@SchrodingersBox]

So true my friend!!!

[@502undergroundmedia6]

@@SchrodingersBox this video popped up in my suggestions and I can honestly say that I learned something. New Subscriber!!! Thanks for the tutorial.

[@miraclechikwem4987]

I like your teaching sir God bless you

[@robbieturnbull4253]

@@SchrodingersBox admitting your wrong when your wrong is the important thing unlike other people who find out what it really was and say oh I knew that all along you admitted your mistake and that’s very commendable I can see why they would of thought it was a crank or cam sensor your not stupid for not checking the ground first you were just performing tests don’t ever feel stupid for making a mistake we all make mistakes and learn from them peace for now my friend awesome video a lot of people won’t admit their mistakes you did that’s the important thing 😊

[@valdabromfield2369]

That's right we learn everyday...that's good troubleshooting...complex problem(s), simple solution(s); simple problem(s),complex solution(s). Very satisfying and rewarding when you solve the problem(s). Appreciate the vid mate n all comments. Be bless

[@frankvoynar6427]

I'll certainly agree with Matt that feeling never goes away, solving a complex problem than moving on to the next.

[@KG-vr3te]

Being a tech brings the money in. I do enjoy the characters I work with and landrover/Jaguar sends me many miles away from home on courses to learn the product. This is easily as good as the courses and I love watching from the comfort of my armchair. He talks perfectly to prompt your own mind thoughts. I love it

[@tinytim9453]

That was beautiful! When it comes to anything electrical, I'm dumber than a box of rocks. But with you, there is something about you that makes it so clear and understanding.

[@SchrodingersBox]

Thank you, that’s what I hope to achieve!! I’m most successful if you can do it!!

[@rgmeyers66]

Thought provoking intelligent content- delivered in a no fluff no nonsense manner. Logic applied over and over again. Thank you for sharing.

[@chicanobluesaz4191]

I knew the problem as soon as I saw the title. Very common issue. Any well versed technician such as yourself should find this issue every time. Good job and great video!

[@mlamont9999]

Can you explain better where this is located

[@chicanobluesaz4191]

Under the driver side exhaust manifold forward of the oil filter adapter, above the oil cooler lines. The ground is bolted to the engine block.

[@riblets1968]

You used your head, applied your knowledge, and fixed the problem. Excellent, sir.

[@SchrodingersBox]

Thanks!! sure beats guessing

[@jamesworsham2312]

Knowledge is the ultimate power. Sometimes we get wrapped up in what we're doing we forget to go back to the basis

[@ag1auto588]

Great video you remind me of Scanner Danner.. I've been a mechanic for 20 years, & I agree always start with power and grounds,, btw on Chevys is common to have problems with grounds especially with wiring traveling through parts that vibrate or under exhaust manifolds or close to them. My hat goes off to you sir for calling yourself a do it yourselfer, shows humbleness.👍

[@dougkelley1266]

Your classes have taught me a lot. I figured bad ground before you called it. Thank you for all you teach

[@jviews1]

My family buys old (> 20 years old) cars and I ALWAYS clean all ground straps I find as a week 1 checkout. . This is why. GREAT VIDEO. Loved how you came to the problem root cause..

[@tshephokgetjepe3162]

There is a reason why I subscribed to your channel, your methodology of fault finding is top notch....all the way from South Africa 🇿🇦

[@SchrodingersBox]

Thank you my friend!!

[@guledmah5872]

You deserve the best technicians award in the USA

[@graemer66]

Yes solving a problem can give you much satisfaction and save you money too. Thanks to you I've taken up your tried and tested advise to know how the system works otherwise you do not have an understanding on what you are working on. Over here in Australia I've found a lot of mechanics not interested in working on my 1999 Z28 Camaro but with your video's I have been able to solve most of the issues encounted. Thank you your friend in Australia. Graeme Redman

[@SchrodingersBox]

Great to hear! “No Worries” lol.

[@MarzNet256]

I've been binge watching your videos and am learning so much, so fast, it's kinda mind blowing. I've been using a DVOM, a knockoff power probe, and the XTool A30D scanner (same as a D7, but with BT and fewer special functions) and practice with it on my 2006 Matrix with 209k miles.

[@SchrodingersBox]

Great to hear! You will definitely be able to get the most out of those tools for sure. that setup is pretty similar to all I use in 90% of my videos.

[@MarzNet256]

@@SchrodingersBox Thanks!

[@nicklala4982]

Love your logical, rational approach to problem solving. Excellent job!

[@SchrodingersBox]

thank you!!

[@twoshedsjackson6478]

Thanks for another interesting video. Quite coincidentally, this is the second video in a couple of days I've seen on the same subject. South Main Autos channel had a customer asking for a second opinion on whether he really needed to spend the $4000 being asked the manufacturer's main stealer to replace his entire wiring loom. After diagnostic investigation, he too just needed to replace a corroded earth strap on the underside of the engine.

[@sheerwillsurvival2064]

Great video great job as usual 👊🏻 I remember as a Chevrolet goodwrench technician back in the 70s 80s living in the rust belt those grounds were always a problem. But I never thought that was the problem on this one looks are deceiving . 👊🏻

[@konyoha]

I haven't had any problems with grounding either...but you really add to my knowledge in understanding diagnostic problems. Thank you, teacher

[@user-sn2lj1jp6q]

Great demonstration and verbal communication. I’m 74, shade tree type, struggling to keep up with how stuff works. I’m a new subscriber. I also view South Main Auto and Rust belt Auto among a select view. Thanks Schrödinger Box!! I’m a builder/contractor so mine is a much simpler world . Dave in Omaha

[@TheCowgirlNiamh]

Fantastic work Matt! 👏👏👏 My initial thought was wiring because you said intermittent but I still would have followed your usual method because it really does help give direction 👍

[@SchrodingersBox]

Good call! Yes there are many many many things that can cause an intermittent that eventually becomes consistent. as you said it’s best to just follow the procedure and whatever it is will be found every time.

[@Kaunas-rx3qv]

Great work Matt. Thanks so much for another excellent diagnosis.

[@GreatDataVideos]

Thank you for taking the time to methodically teach us, as you always do.

[@SchrodingersBox]

My pleasure!

[@jazzstarish4186]

Greetings. I have a 2005 Chevy Zafira 1.8. No spark with new coil. The ignition coil connecter (5 wires 4 go to each one). The 5v reference on each on is around 4 volts. Does it have to have 5v to spark? Can I take a test light on positive battery and supply it to one to spark? 12v is too much. Thank you.

[@SchrodingersBox]

You could do that yes. but there also needs to be a 12V on one of the wires. has to be.

[@glennmiller5451]

@@jazzstarish4186 loop l.

[@LinoHart-fr2mj]

I have watched a couple of your videos and not only learned a few things but also entertained. Thank you

[@SchrodingersBox]

Thank you! I try to keep it fun.

[@paulgarcia1040]

Thank you so much. I'm checking the ground on my 99 gmc 5.7. The way you explained this is 2nd to none. Everett Garcia Wichita Kansas USA

[@Ravenshadowson]

Love your videos. I learn so much from your videos

[@shepherdguy]

At the very beginning of the video when you stated the shop had checked and replaced the cam and crank sensors with no luck, I was thinking in my mind you were going to discover a bent or damaged tone wheel, but that thought quickly dissipated when you showed the count and speed. I was not thinking a missing ground. Great information! Love your approach to troubleshooting.

[@SchrodingersBox]

Yeah good thinking on tone wheel- I actually have a video where that was the issue.

[@bludhoun9016]

@@SchrodingersBoxreplaced a transmission on 03 Silverado and now crank but no start . No spark from coils and no fuel from fuel pump . Constant ground from (A) and keyed power from pink . Still no start. Wat could this be that’s not allowing truck to start ?

[@SchrodingersBox]

What is the CKpS signal voltage showing?

[@xj31]

How easy it is to overlook the basics. Seems like whoever looked at it before you could not see the forest because of all the trees. Good no nonsense common sense diag there, thanks for sharing

[@Ben111778]

This was a great video! I appreciate the detail you go into, it provokes a great amount of thought with revealing connections so that in turn, I could figure out that I'm having back emf issues with my 73 Mopar 360 causing the plugs not to spark and am missing an engine to chasis ground on the tranny end of the engine!!! I think you just solved me a whole number of intermittent electrical issues I've been having! Thank you!

[@JohnDoesGarage]

I love those kinds of challenges myself. There is a very good friend of mine who is a factory trained technician with decades of experience and he told me he rarely ever sees a sensor failure. According to him the vast majority of the time it is a wiring issue. Case in point. Thank you for your amazing content.

[@SchrodingersBox]

Yes I have only seen 3 in almost 10 years

[@cpcoark]

The first big clue I picked up was the customer stated the no start was intermittent. Then not starting at all. More than likely that would be caused by a bad connection. Temperature affect would be second if it was consistent under hot/cold conditions

[@SchrodingersBox]

9/10 times that’s exactly how a crank sensor fails though. or a sticking IAC, or a failing fuel pump.

[@sandygrungerson1177]

@@SchrodingersBox yes i was curious what your initial opinion was on the cause, given the intermettant description, but i would think your diagnostic would work regardless as you would still see the ground/no-ground condition with the light

[@michaelszczys8316]

@@cpcoark bas connections will really mess with you. I have seen a bad battery connection completely imitate a ' last leg and down to dead ' condition when really it was fully charged and good for 100 cranks.

[@TheDisgruntledMechanic]

Nice hoodie Matt! Thanks for the shout out. I bet the Pico comes out on this video. Now back to the video.

[@SchrodingersBox]

Hahaha I actually already had it out of the case ready to go but never went that direction!!

[@bob8776]

You’re so right about the poisoned well. It’s been my experience that whenever there’s a general consensus about what the problem is yet the vehicle still isn’t working, it’s because everyone is wrong or don’t have any idea what they’re talking about. Go through the process of eliminating potential issues yourself and zero in on the real problem. You’ll waste less time and money and you’ll actually fix the thing. I literally just picked up a 96 Chevy for dirt cheap because it didn’t run. Guy said it was the fuel pump and had a couple other guys tell him it was as well. Ten minutes and an $18 coolant temperature sensor later I was driving away in a truck that runs great and is in pretty decent condition

[@minamcconnell9932]

Absolutely the most in depth video we have seen for problem solving a vehicle. We are definitely going to check our ground wires and see if our vehicle will start. Definitely got us as new subscribers. GREAT JOB!!!

[@SchrodingersBox]

Glad to hear. Just check for an open ground first. It will save a ton of time.

[@minamcconnell9932]

Will do tomorrow. We changed every sensor already and still crank no start😵‍💫 🤞 it's a ground. Will let you know how it goes. Best UTuber that we ever watched! Subscriber for life!

[@gilberthale7777]

From earlier on in the video my mind was screaming, "It's a bad ground!" Not just a gut feel, it was more that when you saw the injector signal was firing, and the test light clip on the positive terminal and no test light when you touched the ground circuit wiring, the jig was up. None the less, what a brilliant process, even if you did go to a few more tested areas than "needed." I am glad you did take a longer path to get to your end point, as it gave me a chance to learn more about that GM circuitry. My strength is more in the First Generation Mustangs Shelbys (1966 - 1973), and with Ford systems from the 70s and 80s back when I was working as a Ford tech in SoCal. I can tell you this for sure, your wiring diagrams are superior to the older Ford schematics I had (and still have) to work with, It was not until 1972 that we really began to see fairly decent wiring schematics, and 1973 brought us some even more decent diagrams,. Yet, the wiring schematics you showed are truly superior to the kind of detail I have from my schematics sources (all Ford publications). Anyway, I am a new viewer of your videos. I look forward to seeing more. And, I understand that "rush" when a hard to diagnose problem is finally tracked down and corrected. There was hardly anything more satisfying to me back in the day than figuring out a problem that had gone to so many other technicians, and even other dealerships, before I finally had the problem car come to me. Often the really obscure issues turned out to be ground related. I always enjoyed that logical challenge found in where I chose to begin my diagnostic approach, and why I then chose to go to one "next step" to check as opposed to another one. The logical diagnostic approach I learned in the auto industry served me very well when I went over to the computer industry. I loved solving programming and circuitry issues by applying logic. Now retired, I spend a lot of time sharing things I know about diagnosing and repairing First Generation Mustangs and Shelbys, which are applicable to all older Fords and even other makes. My KZbin channel has feeble content in comparison to what you have, so far. But, considering my narrow focus I am pleased so many folks have found it to be useful. Anyway, I get why you are sharing your videos, and appreciate your sharing back to the industry we love so much. An aside, I also appreciate when you leave in the goofs and erroneous.needless side trips you take in your diagnostic approach. It lets me get a better feel for where your thinking is. And, it lets me know that indeed it is okay to take a needless side path during a diagnostic approach. Some of my more powerful insights have come from taking needless side trips, where I have a happy discovery I can use at some other time. Anyway, Kudos!

[@SchrodingersBox]

Thanks, and yeah I totally can’t believe I didn’t check the ground while I was checking power but like I said, you can get your well poisoned and also it’s really really distracting when you are also filming. Had I not been filing I’d have tested the power and the ground and then checked signal.

[@gilberthale7777]

@@SchrodingersBox No matter, you rock! In the end you found the problem, and even demonstrated proof of the error before locating the point of actual cause of the error.. Who cares if a few extra paths were taken in the meanwhile? It will not be me tossing a rock at you! If I had to choose between efficient and effective, I would choose effective every time.

[@23hublock1]

You have the rare ability to explain complexity in a way that makes sense and is easy to understand. You would also make for a very good lecturer at a university....even just a few hours a week would benefit so many people.

[@SchrodingersBox]

thank you! I have been told this quite often. Maybe a gift.

[@onegurl9]

And hopefully benefit his pocket book too.

[@BellaRocko]

You are an amazing teacher and diagnostician! You fix cars by THINKING! Thank you thank you thank you for sharing!!!

[@SchrodingersBox]

Wow, thank you!

[@sergiorivera8170]

Very comprehensive analysis of the possibly causes of the issue. THANK YOU.

[@bernardaflores1720]

Great video. GM cars in the rust belt are known for electrical gremlins caused by bad grounds and grounding straps.

[@johnshinski2994]

An absolutely great lesson. Thanks

[@Briandutoit-sl2nd]

Thanks my man great lesson

[@richardbizzoco624]

great job. i just went thru a full-on diagnosis (crank-->no start) where current was interrupted and there are so many possible things it coud be. Mine was an older car with a ripped out alarm system and many cut wires. Ultimately it turned out to be an EFI relay that worked, but did not transfer current from pin 87 to 30 and replacing the relay brrought back the check engine light, which did not light up with key on. So solved. interesting and well done video.

[@jarrow708]

Just want to say thank you. I have a truck in the shop and it ran when it came in. I replaced the oil cooler lines on it. I went to start the truck and it was missing really bad. turn the truck off and would not start again. I did the same thing the other tech you talked about. I never thought about the ground. I bumped into your video late on a Friday. Just got in on monday morning and quick checked the injector pulse. It was working. checked the ground on the coils and there was nothing. Thanks for the help. I was really lost on this one.

[@SchrodingersBox]

glad to help!!

[@MagnumOpusSRT]

Excellent diagnosis. It seems many underestimate or overlook grounds. Your methodical approach is appreciated. Thank you

[@SchrodingersBox]

Yes even I overlooked it at first. in 9 years this is the first corroded ground I have ever run into.

[@DANNYN224]

Great diagnostic and love learning from you

[@SchrodingersBox]

Glad to hear it!

[@robertqman5751]

Great diagnostic skills ... Yes .. Your video's are very helpful. Just found your link recently and glad I did ... 👍.. Thank you for what you do.

[@Mark.N]

Thx very much for this..I heard "intermittent" at first...that clue made sense as well...now back to my son's 2008 Altima with a new alternator that is not charging the battery...wonderful...

[@grizz5431]

Stating the obvious, at 10:00, my brain was screaming "You need to check the ground!". That's something I learned back in the late 70's with the advent of computer controlled fuel and ignition. Because some of the manufacturers attached ground wires in stooooopid places like thermostat housing bolts. But, good job. I'm surprised someone didn't catch it before it came to you.

[@deanb949]

Problem is today, the techs are too young to have been exposed to the daily run down to the last wire of systems they diagnose today. Back in the 80's the automakers were still (sadly) cutting their teeth on EFI and all the wiring logistics that goes with it. I got out the buiz in the mid 2000's and still take the "check all the basics" routine first and foremost while they're relying on the analyzer's leading them to component failure.

[@SchrodingersBox]

Dean, What do you mean “check all the basics”? If you have a P0171 lean condition on a v6 engine what are the basics you use over relying on “misleading analytics?”

[@deanb949]

@@SchrodingersBox As I've stated I haven't been in this field in well over a decade. When we had codes, we backed up immediately with a multimeter or our 4 ch. Fluke storage scope what the related component's parameters were. We didn't just jump at parts replacement. The meat of my comment was aimed at the chaos of 3 domestic and a plethora of imports all doing their own thing before OBDII standards were in place.

[@deanb949]

@@SchrodingersBox Didn't say the analytics were misleading. The techs took the data as a set in stone parts order.

[@SchrodingersBox]

Not sure I follow that. Data is just data, it’s not a direction and certainly not a conclusion on a part. I don’t see how that could happen. Maybe an example of your method vs a young tech method on my 0171 situation I described?

[@at_3831]

I scored very high on the ASVAB test so I was fortunate enough to be trained in aeronautical electrical and mechanical troubleshooting it’s a skill not easily learned but very easy forgotten when not used. This video is extremely knowledgeable information for anyone learning how modern automotive and equipment work.

[@MasAUS]

Great video, and your ignition video is 1 off the best I’ve ever seen really nice explanation , and the most important think is the way you explain, it is so clear and understanding , you do put 100% effort to make sure others understand.

[@SchrodingersBox]

Thank you very much!

[@8307c4]

Wow... I have a 1995 Volvo 850 with this crank no start issue... I think I will follow your set of steps in the diagnostic, that was pretty incredible.

[@SchrodingersBox]

it works every time!

[@biglevstergarage]

Spectacular job Matt, good find as well. I had a couple experiences like that as well with my scope on a rope too. Someone a while back spent hours with a buddy trying to figure out why his 89 Chevy truck wasn't starting, they took out the fuel pump and half the top side of the engine apart. Truck still didn't start and they spent a good 6+ hours on it and scratching their heads, like why isn't it starting. The guy calls on me to check it out, go to try and start it, no start, look at the dash, no check engine light, pull out the trusty test light look for ECM fuse, blown fuse. They get a new fuse and put it in, starts right up, told them it may blow again depending on what happened to blow it the first time, but started it up a few more times and let it run and it didn't blow the fuse again. Spent under 10 minutes figuring it out, where the guy and his friend spent over 6 hours and half the truck apart trying to figure out what was wrong. Its thanks to many people like yourself on here that taught others like myself what to do, where to look and stuff. Great job!

[@SchrodingersBox]

Great story man!! Thanks for sharing that!!

[@JohnSmith-pb1dd]

Thank you, amazing video, you are a great teacher 👏

[@SchrodingersBox]

Glad you think so!

[@davidsheward2113]

Thank you so much! Having the same intermitten issue with a 99 Dakota. I Have replaced fuel pump, sensors, & key electrics ..now I will look for a bad ground!

[@TheDisgruntledMechanic]

Huh! I was wrong! no Pico. But to diagnose with basic tools is awesome! It was the hoodie you were wearing that helped you diagnose this!

[@SchrodingersBox]

it did help or I’d have frozen to death!!

[@InsideOfMyOwnMind]

The hoodie always helps.And if you have the baseball cap underneath it even better.

[@bchrisl1491]

Good clip. well done. Eric O had a similar case over on South Main Auto a month or so ago. turned out to be the ground strap between the motor and the firewall completely corroded away. BTY that connector is a called a ring connector, and that one is am “open barrel” design crimp. They take a special die to crimp, but they are better than the barrel type crimp electrically because they have more surface area between the crimp surface and the wire, reducing resistance of the crimp.

[@SchrodingersBox]

Hahaha I was trying to remember the name of the stupid connector lol!! Yes “Ring connector” was what I was looking for but my brain wasn’t working lol. Good to see you back again btw.

[@bchrisl1491]

@@SchrodingersBox I have shifted to working on marine diesel and boat issues these days. I was very pleased to see that a group of technicians wanted to see this clip as a learning device. I’m out there lurking most days.

[@wyattoneable]

Nice sweat shirt. Mike is a great guy. I smiled when it started. Following a path of solid diagnostics wins every time. Great video Matt.

[@SchrodingersBox]

Couldn't agree more- he is a class act and the sweatshirt is quite comfy hahaha. I wear it whenever I have to crawl under a car in the snowy weather so I don’t ruin my Schrodingers Box sweatshirt hahaha

[@scottallen5269]

I failed auto shop in high school. In my twenties and thirties, I always took my vehicles to a mechanic for everything. At 46 I decided to learn about my truck and wanted to do everything myself. I’m 50 now, and I’ve changed my oil and filter, ignition coils, radiator, brakes, starter, wheel bearings, heater core, fuel filter and lines, wheel hubs,power steering pump👎(that one sucked) And other tune up type stuff. But this!!! This problem with truck has been a pain in my ass for so long I’ve called it a demon… like Christine. Truck would start, sometimes it wouldn’t, when running the electrical system did whatever the heck it wanted to. Always resetting the system, and having to put in the code for radio and security, sometimes the idle was perfect and sometimes there was a slight hesitation… once in a while it would choke out. Even having to push the gas above idle to keep it running and not be stranded. Then it would run perfectly for months… and I run my truck. I’m always off road, in the mud, 4x4 driving( even fixed it when the actuator wouldn’t engage) And pushing 75 down the gravel road in my 2001 Chevy Silverado 2500HD 8 cylinders pumping… and doing donuts around corners… … … then it cuts out at the stop light on The way home… 🤔 After missing work today and troubleshooting it with this time, I concluded it has to be a contact problem. I need one of those testers… man that would help. What I did was, because my truck would loose power completely trying to start it this time, I left the key to on position… and started wiggling wires. I wiggled enough wires I was loosing hope. That’s when I found this one wire under the motor… tucked neatly and hiding for protection… I think? I found that f&@)%#!!! Wire. But first I wanted to listen to a professional before getting ahead of myself. That’s when I saw this videos title. I’m soooooooo glad I did. You helped to answer the “why” and technical terms and how your breakdown/approach for this situation. The moment that you were at a loss, and nothing was making sense… thank you for that. I felt like an idiot because it took me so long to figure this out. Thank you for filling the voids so I can better understand what I’m doing. I’ll finish this book now. I felt damn good and I pumped my arms in the air too, when I figured it out. Not bad, for a journeyman Carpenter/craftsman, that failed auto shop. It was awesome what you pumped your arms in triumph!!! Sooooo cool

[@spelunkerd]

That was a great case, I like the way you took us along to follow your thought process. I was a little puzzled by the wiring diagram, because we don't see all of the electronics there. The wiring diagram notwithstanding, it looks like grounding of the primary side is separate from the PCM, triggered by a simple square wave positive input along the signal wire. That would reduce the chance of inductive voltage spikes reflecting back to the PCM.

[@SchrodingersBox]

Thanks Dave!! Great to see you again!

[@spelunkerd]

I went back and looked at the Alldata wiring diagram for my old 2000 Suburban. It doesn't have as much internal detail but they do say that the trigger for firing is a ground signal that turns on and off inside the PCM. So, ground side switched on the signal wire, at least in my old beast.

[@mechanic_marky]

Nice find. I also love being able to fix problems that multiple others were unable to find. Keep it simple.

[@SchrodingersBox]

That's the plan!

[@miked1372]

Thanx! I had a no spark issue but ground ohm test was good. I checked my G102 anyway and sure enough it fell off with little effort. Corroded. It was dropping out soon as I cranked it, weak ground. Ran new ground and all good. Thanks for this. It was making me nuts

[@mynyasabut]

This is generally cause most technicians think in terms of 12v plus, ignoring ground issues or get lost thinking obout sensors, your aproach is more efficient i loved this video, i work audio systems and a client mentioned a problem with his engine, it turns out another mechanic forgot to reconnect the physical batery ground so the car was taking ground though the engine block wow! i just recconected it and voila! the engine problem went away when other 3 shops couldn't find the problem

[@abdul-kabiralegbe5660]

Great video! I read (see bottom) that the Low Reference on those ignition coils was an ECM sourced ground which is a dedicated ground for the coil electronics. The chassis ground is meant to supply a ground for the actual coil windings, but can supply the coil electronics too if the Low Ref is down. This system contrasts with Toyota's 4 wire ignition coil where the fourth wire is the ignition confirmation signal (IGF) telling the ECM that the coil fired. Source: There's a PDF titled "Coil on plug ignition - the wired differences" by Matt Dixon which explains this and more. A quick internet search will show this PDF in its result.

[@ChipperTheChipster]

No one thanked you for this wonderful source of awesome information!!!

[@abdul-kabiralegbe5660]

@@ChipperTheChipster Thanks!😊

[@simonilett998]

Hey Matt, love your work mate. I don't believe GM use the brown wire as a confirmation signal like Toyota etc. The brown wire in this design is a common low reference/ground internal to the PCM, shared by each coil igniter transistor, effectively it's a constant path to ground for all of the primary coil windings. The open ground you were chasing is of course the main ground for the secondary coil windings. However, the PCM may still be capable of monitoring this common primary/transistor ground for coil current/over current purposes, and maybe to detect misfires etc.👍

[@endurofan9854]

mornin sir, i lack knowledge in this, so i'm pretty curious, so that pattern ow wires on that coil means 2 grounds? one for primary leading to PCM and one for secondary leading tothe battery - terminal/body, and one positive from the battery and one positive fron the PCM aa the trigger for cut-off on primary... did i get it right?

[@simonilett998]

@@endurofan9854 Yep, pretty much spot on mate. One pin (pin D) is a shared positive supply fed via a fuse (one fuse for odd bank, and another fuse for even bank) to power the primary coil and internal coil pack electronics. One pin (pin C) is a square wave switched input from the PCM controlling the primary coil transistor. One pin (pin A) is a shared constant chassis/battery ground, probably for the primary coil transistor to switch to. The last pin (pin B) is a shared constant ground, grounded within the PCM, probably for the internal coil pack electronics to ground to, and maybe the PCM can also monitor this wire for self diagnosis functions etc. Pin A and pin B may actually serve oposite functions to what I've stated above but I'm not 100% sure, but I can confirm they are both constant grounds and can be tested as such. Hope this helps👍🇦🇺

[@SchrodingersBox]

@endurofan9854 correct.

[@daquilema2011]

Thank You Math, for post this video from your paid channel . Heats off

[@sseef11]

I have the exact same problem with my 2001 Tahoe. So I will be checking the grounds. Thank you for your videos

[@kartamap]

The Disgruntled Mechanic-subscribed !

[@TheDisgruntledMechanic]

TY!

[@randybeard6040]

I use to work with a guy that had a IQ off the Chart, he had Total Recall on everything he read, could resite a Dictionary and carve a Gun stock from a 2x6. This guy could make a couple checks on your engine and tell you what was wrong. I had a recently overhauled engine in my car-one night when we got off from work at 12 midnight, temp/ about 10 degrees, my car would not start, only turn over, he instantly told me that it had jumped Time, I told him that it was just overhauled several months ago-he said well they didn't replace the Timing Chain so he just advanced the plug wires on distributor and engine fired up as it should. He said now go back to the guy that overhauled your engine and tell /ask him why he didn't replace Timing Chain, of course guy denied that he left old chain on my car...

[@KWAHU93]

@@user-pl1uj5ks4mgoogle advancing a distributor.

[@SuperReznative]

@@user-pl1uj5ks4m hah , that the difference experience "brings to the table ". I understood the very thing he was describing about the timing/ plug, ..and it also took me back 30 years when I had to tow a car ,home from far away, because of that that issue. Time jumped.

[@robertbirdsall4571]

The Diagnosis Captain does it again.Well done.I now have a new direction of ingaugment to go..Thanks for your videos, worth every dime. Kalamazoo, Michigan

[@SchrodingersBox]

Thanks Robert good to see you again!

[@eduardoalba3012]

Man you’re amazing at what you do u make it look so easy and the way you explain things is at another level man ! God bless you and thank you!

[@SchrodingersBox]

I appreciate that! Thanks for commenting!

[@lanieeve1485]

yes,...it is always helpful and fun to learn from you with your knowledge and your sense of humor thank you very much for taking the time to make things easier...

[@SchrodingersBox]

What a nice comment!!

[@skoff1214]

Im into the same issue, crank but hard starting at cold start. thank you for this content and i will try this as reference.

[@BryTrapStar-op8sy]

Thanks for the information. I've literally been dealing with the same type of trouble with my 08 Tahoe and now I'm going to take a look amd i hope i am dealing with the same problem. I'll come back and let you know how it goes.

[@nickspua1096]

Mate, I am non technician but also have learned so much from you. Thanks.

[@SchrodingersBox]

Cool, thanks!! Always appreciate the DIY's since that's who we are!!

[@rodbeaty6704]

i yelled at the screen when you checked for 12v input and skipped streight to signal checking lol great video my brother

[@foreverwood1963]

You know how you can have several teachers that all teach math but you can't pass some teacher's class but there's that one. That's you! It's taught that way. I love to see your videos.

[@SchrodingersBox]

I do know what you mean. Thanks for the compliment.

[@TheMopar59]

Thoroughly enjoyed that, great explanation.

[@toddcott9510]

Pre supposing is something we all fall for. Great video.

[@raycook1503]

Such an awesome video. Shows that other areas can cause problems thatcwere never thought about. Also some ignition systems are hot at all times, and the ground is turned off/on to fire coils and injectors as needed.

[@user-pg8kh1pm2o]

I have a 2002 Chevy trailblazer. It just died. All of a sudden I change the fuel pump fuel filter, coil, packs spark plugs starter oxygen sensor fuel regulator, still cranks no start I am I just don’t know what it could be

[@SchrodingersBox]

What data do you have?

[@grenvillephillips6998]

Great to share in Matt's total chuffedness - I always enjoy a happy ending!

[@SchrodingersBox]

That sounds dirty lol

[@grenvillephillips6998]

@@SchrodingersBox To be chuffed is a British expression meaning delighted. I wasn't sure whether it was used in common parlance in the bars of Benson, Arizona. But soon maybe?

[@Back2dkicks]

Man, I truly appreciate you for making this video.

[@SchrodingersBox]

Glad you enjoyed it!!

[@biz4twobiz463]

great diagnosis!! The ground wire like that is very common on GM vehicles. Merci

[@jimmykulik3438]

Such a rush! Thank you Matt. Fixed with a $2 harbor freight test light. 😊

[@kinglangren]

ThTs so true about bad or certain information. I was looking at my friends truck and he said his fan wouldn’t turn on and it was overheating. Spent too much time looking at the fan , which it turned out to be a bad water pump and the fan was fine. If he hadn’t told me about the fan I would have found the bad water pump issue fairly quickly.

[@carlm2590]

Because you helped the poor with their auto repair I thumbs up every video you publish. God bless you. 👍 and I’ll subscribe to your pay content.

[@SchrodingersBox]

Thank you!! yes I have done a lot of free work lately including this one.

[@jamesankiewicz3141]

There is some deep fixing knowledge there! Thank you

[@Jmsrestomods4824]

You are amazing brother..... you have one heck of a way with teaching people. Thank you for all of your help and guidance!!!

[@SchrodingersBox]

Oh wow thanks!!

[@brettmills2470]

Great work and video, that’s about the best way to do it! I’m going to test that ground early on if come across this type of issues! Thanks! 🙏

[@Edi-01]

Men I have learn so much from this guy and I always try to explain to my friends how this things works and how they function your the best men

[@SchrodingersBox]

Much appreciated!! Thanks for watching!!

[@petermaina2281]

Thank you senior,you have helped me solve very many problems.❤

[@johnmorse5617]

Thank you for taking your time to educate me. I found you a good teacher, a vary human one . Thanks again sir .

[@SchrodingersBox]

Wow, thanks!!

[@michaelharmon3384]

Love your approach and my journey as a weekend laboratory(my garage lol) scientific diagnosis technician has definitely taken years. I am 55 years young and by the time i was 23 I figured out the value of a year specific service and repair manual was worth $300 in knowledge over a $17 haynes and $300+ in unnecessary parts. Cracking open that first one was like a zen Buddhist must feel when enlightened. No more "this is much too complicated for you take it to a qualified shop" from Alignment to complete Transmission rebuilds. It was the "RED PILL" of Auto. Escape from the wrench monkey matrix.😅

[@bromobb6510]

I'm definitely subscribing I changed everything and still nothing and now its in the shop and I just paid 600 for a ignition switch that I didn't need so when they fix the ground and it starts we should be even right lol.

[@JavierHernandez-vw2ny]

thanks for options you came up with some people wont share thank you

[@Mr2004MCSS]

Nice video. I was expecting you to check grounds after checking the power and was surprised when you didn't. I just subscribed to your channel so that I can see all of your info and videos.

[@SchrodingersBox]

Thanks 👍. Yep I absolutely would check grounds but as I mentioned I think I was so set on a CKPS issue I just forgot to do it!

[@ProfessorMikecarGuy]

Great explanation, don't forget your grounds!!

[@mintyperfectionable]

LOVE the videos. I’m not trained at all, but I do all of my own work until it gets to the really complicated or sensitive replacements, and these videos are insanely helpful. Side note, at least half of the time while you’re talking, your voice sounds to me like crispin glover 😅

[@SchrodingersBox]

Hahaha someone else mentioned that before too lol. I don’t see the similarity hahaha

[@davidmedley9652]

Great logic and clarity, thanks for another great video.

[@SchrodingersBox]

Thanks again!

[@A_Litre_of_Farva]

This proves yet again, check the simplest things first and don’t be quick to throw money at it with new parts! Thanks ❤

[@Ottonic6]

You always have great content. I need to subscribe to your premium channel so when you refer to the content I can watch and understand... For the price of a gallon of gas (well maybe not), even if I only chime in a few times a month it's still a win... On this diagnosis, Powers & grounds. A lot of times that's one of your first tests. Thanks Matt!

[@SchrodingersBox]

thank you! just a point though-Powers and grounds comes after you know what system is at fault. if you want to Check powers and grounds then you are going to have a long day because there are 400 on this car and many are shared.

[@edge24edge]

Great Video !! Grounds are important . Thank you Sir .

[@benniedonald]

I truly appreciate this video. I have a 98 dodge ram 1500 5.2. "Stop laughing" 😅 My starter burned up and now. I have this problem unfortunately I knew it had a parasitic draw. I eliminated all of them. At least I thought I had. Most of it was due to a poorly done radio installation. Watching this helps me understand the ground is probably the culprit all this time. Or at least gives me an idea what to look for. Thanks again for the troubleshooting tips. 🎉

[@SchrodingersBox]

Excellent!!! You are approaching it correctly for sure. You'll get it soon and its so satisfying when you solve it!

[@billmonroe8826]

I already fixed mine last summer at the same location for my 2007 silverado. lol Good video.