GM Bypass Ignition System Operation (part 1)
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- เผยแพร่เมื่อ 8 ก.พ. 2025
- Part 2 • GM 3300 Intermittent n...
This is a unique design when it comes to ignition systems. One where the ignition module can control spark completely independent from the engine computer and is something GM used for many years. Starting with their computer controlled distributor ignition systems in the early 80s and continuing in many different waste spark designs well into the late 90s.
The engine being discussed is an older GM 3300 but the material can be applied to all GM bypass ignition systems.
This lecture was given to my class in connection with the following case study:
GM 3300 Intermittent no start rough idle (shorted injectors)
• GM 3300 Intermittent n...
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Topics discussed
How a bad ignition module can cause a no injector pulse condition with good spark.
How electronic spark timing works
What is the difference between "Module mode" and "EST mode"
what the "reference "wire is used for and why you want to remember the wire color
how to perform a bypass test on the reference circuit to check for injector pulse
Playlist
(Chapter 22) No Spark Troubleshooting, Ignition Coil & Module Testing • (Chapter 22) No Spark ...
For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available at www.scannerdanner.com as an eBook or paper book.
Want even more diagnostic training? Whether you are a DIY trying to fix your own car, someone looking to become an auto technician, or a current auto technician that wants to get more into diagnostics, subscribe to ScannerDanner Premium www.scannerdan... There is a 14 day free trial.
On ScannerDanner Premium I will bring you right into my classroom at Rosedale Technical College. You will find page for page lectures taken right from my book as well as exclusive classroom type case studies. What is so special about these classroom case studies? I pull live problem vehicles directly into my classroom and we troubleshoot them in real time, using and applying the theory and testing procedures we learn during the classroom lectures. There is no better on-line training of how to troubleshoot automotive electrical and electronics systems anywhere!
Disclaimer:
Due to factors beyond the control of ScannerDanner LLC, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. ScannerDanner LLC assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. ScannerDanner LLC recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of ScannerDanner LLC, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not ScannerDanner LLC.
Thanks for the very clear explanation. We need more guys like yourself, who understand scanning but aren't committed to one manufacturer.
Absolutely love the way you present information Paul. Even when I understand something very well, I have trouble explaining in easy to understand ways. Thought I was a pretty smart guy until I began teaching. Found out pretty quick how much I didn't know. Keep up the great teaching!
For sure, being a teacher, you really have to learn the subject, more than you ever thought you needed to.
Thank you!
@@ScannerDanner please make videos on how one touch auto up and auto down windows works on any car... Thanks in advance.
I love the classroom videos. My better part of being an advanced engine performance guy was when I started using theory of operations and a labscope. Rosedale Tech should be so fortunate to have such a passionate instructor
WOW! I'm quite impressed and now more knowledgeable on ignitions than my mechanic and electrician skills use to be. You make me want to sign up for school now...
I have an online class on my website if you're interested www.scannerdanner.com
@@ScannerDanner sir, let's take an example about ckp sensor.
1. The car starts well, everything ok. Now, while engine is still RUNNING, if the ckp sensor is unplugged or removed, will the engine stall??
2. I removed the ckp sensor and had someone to crank the engine at the same time, I'm creating blocking and unblocking the magnetic sensor quickly with metals fast enough to send signals to the ECM. At this manually signal inputs to the sensor, will the engine CRANKS AND RUNS??
@@tnamen1307 1. depends on the car and the design of the cam sensor signal, in general almost all of the older cars will immediately stall
2. nope, the crank sensor is timed mechanically to piston position (top dead center of a cylinder) and you will never be able to match the correct timing signal by doing that
@@ScannerDanner hi there sir i been working on cars along time i pick up a 95 Camaro 3.4 it has spark but no injection pulse i put a new fuel pump and new gas tank do yea any ideas on how to fix it i have gone broke trying to get it going
@@JonOffgrid do you have fuel pressure? Any trouble codes? Is this a sequential injection system or a group fired system? Can't remember. If it is group fired like the 2.8 and 3.1 of this era, one single shorted injector can cause this
The way the bypass system was explained was simply awesome. Thanx
Absolutely fantastic video I think I learned more in the past few minutes than I have in the past couple years about cars
Paul you are the legend of diagnostic electronics vehicles. I like the way you teach.
Hey Man, good video. I've wrenching for a lot years and you just made my day. I mean I've been doing this for 40 plus years - but usually hard way compared to yours. Actually been watching your channel awhile. Been supporting myself pretty well wrenching for myself 17 years near Denver.
Anyway, caught this one right on time. My neighbor moving on after 30 years in the house gave me a '89 Pontiac 6000 STE (AWD) in go condition except busted 3100. he'd pulled a 3100 supposedly from a '93 said was running, but what I saw was later OBDII. My good friend Brien - great dude - is dying from cancer, talks through a hole in his throat and never smoked. Doesn't have long. He's driving this worn out Envoy thats junk. (Actually trying to get the security to relearn a key and he using my truck for his medical stuff) Brien likes this car. So it;s over here. He dropped the subframe w/powerchain. I switched out the engine, everything bolts up. Also, was told is was pulled from a Pontiac but one different mount. Was side by side comparison to a 99 Buick Century perfect match.
We'll have to modify the fuel lines and egr, then figure out how to wire it in, its electronic without a vacuum line, and heater hose routing. The guy brother had scrapped the 89 intake and throttle body, but saved the injector harness and it plugs into 99 injectors. All 6 have same color code and I could only guess the routing. It has 2 crank sensors, one to the coil pack match. extra one at harmonic. Also, cam sensor. Same coil pack just different location. Engine is in, it's back on the ground, just trying to find time/money to finish. Probably fire is up in a few days. But this kinda matches this vid and had to say thanks.
And again for your scanner stuff. I mean I used a solus pro for years and now I have a modis edge. Trying to learn everything. I'm learning the low amp probe, secondary coil stuff. I have a little website that I have back up after being down 5 years. Going to link this video there, probably on Tim's Build's button. www.timthemechanic.com/
Thanks Again for all your vids.
This video might be an 'oldie' but it is certainly a 'goodie'. It influenced me to open the factory service manual on my '93 Chevy Corvette 5.7L LT1 to see which ignition system it has (wiring diagram)..... it's a bypass type. Thanks for the inspiration to learn more about auto electronics Paul
That was the most distilled and concise explanation I've heard, describing construction and function of a bypass system. You young techs need to pick up Paul's book. I have been in the trade for 31 years, and grew up in the business prior to that. I Just purchased the book myself... I could have made a lot more money if material like this was available back when I started out. Thanks Paul, you are a good ambassador for our trade. I Haven't seen any gdi or multiplex? Got vids?
Thanks bro! Would you mind providing some feedback here?
www.scannerdanner.com/feedback#add-comment
As for GDI, I have some stuff on my premium channel but nothing in print yet.
Thank you!
I really like the way you are able to un-pack your topical info...and I believe your viewers would greatly benefit from you taking a moment to review construction and function of the component you're field testing. i.e. looking at spark on a waste spark coil....many techs don't know what that is. It's just a quick reinforcement. I've seen you use reinforcement in class, and it would be good to see in your field work. I will be happy to provide a review of your book; I will be joining your premium channel once I have pre-read your book materials completely. Have a great weekend.
ScannerDanner Premium i have the bypass wire the tan and black wire cut and the car runs but not that good it wont run over 120 km could it be from the bypass wire do i need to fix it or is it ok to leave it cut ? thanks man love ur videos by the way ur the best
The design Paul described and explained in its natural settings was to perfection
Saw this after watching your 2.2 S10 video. I didn't know about bypass ignition systems until today...thanks ScannerDanner!
yep from the school of hard knocks :) (bad calls in the field)
Also it helps to teach. You really think beyond the repair when you are teaching the subject. Of course reading articles, going to training classes, talking to other technicians all plays a part too. This will be 21 or 22 years of field work for me now, with 14 of them spent full time teaching, and I am far from knowing it all. In fact the more I learn, the more I learn I don't know. :)
Man I've been looking for this video for 3 hrs. Thanks man needed a standard ignition breakdown. Awesome job!
I don't know how this channel is less than 1 million subcribes! Good job my master!
this was the best class i've ever taken
Well described. I had a really good bite on this before the video. I'm now 100% on board! Thank you!
Thanks for your videos, i purchased the book several days ago and have been watching your videos. You are a talented instructor and your students are lucky to have you. We need as many well trained techs as possible in our changing industry. There are too many hacks out there armed with a $40 code reader giving real working techs a bad name. Cars are not the same as in the 60s and 70s. Consumers should watch some of your vids and see what actually goes into a proper diagnosis
Very good video, explaines ignition system input and output signals in a very easy to understand format. Paul Danner for President!!!!
I was looking for something different when I came across this video. You produced a really great instructional video!
+Pef273 thank you!
This video just suggested one of mine for ESC. I was kinda proud,lol.
Wow, Cool you pinned that. Now that I know you are paying attention let me say thank you. I've used you as a reference point to go back to whenever I get ahead of myself on something. It's good to solve problems when you are working. Like mental exercise
Good Evening ScannerDanner 🙏 ✨ Have a great day, take care ScannerDanner,God bless you 🙏
Great tutorial thank you 👍
Nick Ayivor from London England UK 🇬🇧
Really thanks from Spain. Now I can understand the GM ignition and my Vette 87 problem.
Very very good video.
Congratulations
+GEARHEADSOLUTIONS.ES sweet!
Thank You. Been dealing with an intermittent no start on an 01 Blazer that is a complete no start now unless using ether(starts EVERY time). This is a big start in solving it. New fuel pump, plugs this past summer. I'll be checking this asap.
@scraiga66 I don't have a video on that but check out the wiring diagram on a 1993 Chevy Cavalier 2.2 (VIN 4) engine compared to a 1994 Chevy Cavalier 2.2 (VIN 4). The 93 version is a bypass system (CKP sensor goes to ICM) and the 94 is completely ECM controlled (CKP sensor goes to ECM). So for no spark diagnosis we need to treat these systems differently. Thanks for the comment
Excellent explanation.
I never made the association between GM and Ford EST/SPOUT.
This really clarifies it.
thanks
@trad444 Thanks for the book purchase and comment! The CKP variation learn is for crankshaft acceleration rates (frequency increases) for each cylinder firing event. I believe this CKP learn is for proper misfire monitoring to take place, not for the 1x and 3x signals, as this is only one of hundreds of designs.
SUBSTANTIAL Sir ScannerDanner
Tutorial great ❤ it thank you 👍 👏 👌 God bless you and all your family around you Sir ScannerDanner
Sir ScannerDanner
From Nick Ayivor from London England UK 🇬🇧
Very good information. Thank you for the explanation. Presentation is top notch.
That's rocket science to me. I am grateful I am specializing in Diesels.
@felmar39 Thank you for your purchase and comment! I am glad you find the information in my book useful.
wow i wish i knew just a 1oth what this guy knows. I hope you keep puting these vids up. Im getting smarter by the vid. Thanks, going to buy your book for sure.
It takes me awhile to start in the morning without my coffee :-) just kidding
I need to know a little more about what your working on to help.
Thank you Paul 😊 Hope you and your beautiful family are doing well in these times Have a very Merry Christmas 🎄 and a happy New coming year your a Great Teacher
This has been quite helpful with my 1993 chevy 7.4L system. My bypass wire does not read in volts but millivolts so I'm hot on the trail ! My truck will start quickly but idle kind of rough with the bypass connected and smooth with it not.
Lol, I've just been doing this for a long time. I really not that smart.
Thanks for the comment
I have seen a completely plugged exhaust cause that. Also a bad coolant sensor which was causing as immediate flooded condition. Also I have seen these early design injectors only short out when under "stress" and test fine with an ohmmeter
Damn you Paul why do you have to be so freaking through!
Always got to do everything right...
@vader2492 Thank you very much. That was a great compliment. It is true what you say about consumers needing educated on why they need to pay for diagnostic time. Most of them think all you need to do is plug in the "computer thing" and it will tell you what to fix. The "free diagnostics" that the parts stores offer hasn't helped this train of thought either.
@fivefortyeye540i Yes they will. Also keep watching, I plan on doing more ignition system design type stuff. Also thank you for the compliment! I really wasn't sure if this type of video would work well or not.
Excelente tema Excelente explicación Tecnica.. Son pocos las personas que trabajan este tipo de información por este medio, con explicaciones de circuitos que nadie describe, y si lo conocen, lo hacen y explican de manera muy superficial, seria muy interesante relacionar este sistema de encendido en Derivación Chevrolet, especificamente en los Impalas 2000 al 2005 motores 3.8 , ya que presentan demasiados problemas con su sistema de ignición y el sistema anti robo ó Passlock.. mucho se le agradeceria si lo hace de la forma tan magistral como explica en esta Clase de este Video
Scannerdanner, will a data base such as Alldata, Mitch tell u what type of ignition system u are dealing with? After watching ur vids I find that I dont know a 1/4 of the stuff I thought I knew. This is the first vid I've seen that shows systematically how it works the sequence in-which what component relays signal to next component to get the system up and running. Very easy for the brain to digest. Excellent 5 stars Scannerdanner !!
you can still have spark on this design with ECM problems. If it is a no start with good spark, the next step would be to check injector pulse. If no pulse you can still have a bad module even though you have spark. If the ICM is sending an RPM signal to the ECM then you have an ECM problem
most times the VAT security system known to crank engine key must be read through the ignition switch sensor that sends the key code to the BCM from BCM to the PCM/ECm tells the injectors and fuel pump and electrical volts to the coils to kick on and start . the ingnitions in GM with computer those pass key ingnitions on most gm known for going bad they sensors get fried out or drop below true voltage signal. i just replaced a ingition switch after the chevy dealership said they could not get it to read on there big Computer that there was no comunications obd with BCM and the PCM/ECM they had 5 of there best Machanics working on it for a month, tore it all apart and they still could not figure it out. this car belongs to a friend of mine, so he got it towed back to his house. i went over there changed out a relay and got my scanner to work reading the obdII system i did a full modules scan and got codes, so next i dug into some researching on these 2001 to 2005 gm vehichles and little do you know, they have had bad issues with the ingnition switches 8 recalls on gm electrical stuff on them. well on the chevy impalas 8 recalls . 5 on the chevy silverados anyways they all have the same Passlock sensor ingnition switches security ingnition lock sensor. make a long story short i got another ingnition switch from a junk yard for 50.00 bucks with 2 keys to it like brand new. placed it in plug in all wire connectors and shifting cable in , and did the relearn key in ingnition procedures steps and walla 4th time started right up. easy peacy. just thought i shared that with ya or for anyone that has had issues trying to figure out why there gm vehicle wont start no crank just clicking.
I like you profecional explanations videos , God bless you.
Get the engine warm and tap on the crank sensor with a long screwdriver. Be careful of the serpentine belt and crank pully. If the engine stalls then you need a crank sensor. As for testing it, I actually have a 3800 crank sensor video that I haven't uploaded yet. I'll try to get that up soon.
Got an example of a GM with ICM that the CKP runs to the PCM? Not the misfire crank sensor. Love your stuff by the way.
When it doesn't start see if you are getting a reference pulse on the purple/white wire coming out of the distributor connector. IT should be a 5v square wave pattern.
excellent work by the Master, i like to know about other system where the crank sensor is directly wiried to the pcm however the cam sensor is wired into the icm
check compression next. if you have spark and it will not start with a fuel source then compression is next. these are known for timing gear issues i believe.
What voltage range does the computer send to the ICM through the WHT wire once it has been bypassed with the 5V through the TAN-BLK wire?
Mitchell On-Demand, best diagrams for us aftermarket guys!!!
Very good video and by the way .I did get your ebook and is very good , thank you so much for sharing your experience with us, good bless you my friend
Got a question on that bypass system got no spark got no fuel it's a 1995 Chevrolet but I've got no spark if I unplug the bypass under the dash if I have a bad ICM can it cause it not to have spark. And it has no fuel control either nor spark control
Interesting video is a 86 corvette part of this system it starts but won't run lots of cut rewired and jumped wires from previous owners
I have a question, you have 4 cable, which cable should be connected to create a bypass. Red/blk and white
@Mark1944089 it's called a multi function switch. the steering wheel have to come off. and if it is a tilt wheel system these can be tricky. the new harness gets fed down the steering column on the inside. not a real fun job
hey paul so on this this dising is it possible to have 170 psi of compression on all cylinder, 45psi of fuel presure key on egn off, and 37psi egn crancking, have injector pulse, and spark on coils, have no shorts on any of the injectors 12.5 of homs on each one, have cmp and crank signal, and still have a no start? i had one like that few years ago it was 1994 buick century customer replace pcm, icm, cmps, ckps, he brought it to out our shop to see if we figure it out but no luck.
Just found your link, I have a 1999 Chevy 454 Vector 7400 V8 7.4 L installed on a workhorse chassis- class A motor home. I have a no crank no start, I replace the starter and I have crank, but no constant spark, I replace the crank positioning sensor and it spark and then stop. so I have crank some time spark, ICM or ECM?
This video is really improving my understanding. Although I was a physics major and understand a ton about wiring, it's hard to find good information on older automotive systems. Any recommendations? Also where do you instruct at?
I'm getting a electric spark timing is grounded code 42 .. do you know what this could be .. i have changed the optispark, coil, ignition module, air flow mass sensor, and pcm .. working on a 95 caprice. Any suggestions?
I haven't forgotten about you. I just need to look at this diagram a little more when I have more time. This is a weird design
how does it work on gm vehicles with no crank sensor or cam sensor. does the timing connector on the firewall disconnect the computer and just reply on the ignition module for starting and running?
Nice demo
Hello I am new in the industry and building my tool set. Do you or your organization offer any sort of scholarship or grants to people like me just beginning in this field? I am interested in buying some basic diagnostic tools and maybe a scope
Paul do you have a link to the case study you did where the work van had a viper alarm system short causing no inj pulse? I swear I saw the video before but can't find it.
I have problem here my gm starter selenoid has R terminal and I want to use it to help my start in winter but aperantly my positive linear dashboard regulator dont alove it ore I did some thing wrong because my dash fuse poped, I have singel hei coil E core type my distributor has a induction triger and the gm 4 pin ignition module is inside the delco distributor as well how can I solve this problem? Reversing the conections on the starter selenoid? ore atach in other place ore terminal on the ignition coio it self? Any way are dc boost converters ore amplifiers a good choise instead? I wuld like to also build oil cooling contained for my ignition coil those hei coils are nice they can take good punch but the wiering confuse my I have a old Opel Monza 82 model the wiering is prity shity in that thing evry thing goes on 1 wire so Im cinde of in big problem when winter comes
Good talk. I'm assuming that the bypass function is to make the engine start quicker because the Ecu takes a few revolutions to initiate the spark because it has to Calc the rpm and thus the engine rotates a few times more before starting. Am I correct in my thinking?
I have a 93 gm Buick 3.8 intermitted no start/spark j think is the crank sensor what wire I need to check?
First let me say thank you and God bless you for you education and help have you provide. I will be very grateful for you answer. The question is pertaining to the information provide in this email. I will like to know if, the GM 3.4 V6 Ignition Control Module can fire its Coils without the ECM/PCM signal and the fuel injectors remain in functioning order with spraying fuel?. I car understand these two signal are LO and HI 3X reference signal. If the ICM need this signal to fire the coils, where can the circuit get the LO/HI 3X reference signal from? Can it be gain from the LO 3X signal on the crankshaft sensor reference signal and the HI 3X reference signal come from the camshaft sensor?.
Thank you Sir
What determines this (bypass system or not) is where do the crank sensor wires go? If they go to the ICM first, then it is a bypass system and spark is controlled by the ICM directly during cranking. If the crank sensor wires go directly to the ECM first, then the ECM is always controlling spark. Make sense?
Learn from the best
Wow! Got a '93 3300 that *always starts*, "turn key"instant stalls,from 1-30 seconds on average. yesterday it ran for 15 minutes twice!.. then stalled when I tried a test drive. I've ruled out fuel by fully testing, all is textbook pressures. It started 3 months ago, on warm engine after a load like going up a freeway on ramp. the next weeks, it settled into a shut down at any speed, throttle position, temp. Have new ICM,CPS,fuel relay. Now I'm lookin for a broken wire... any thoughts?
on this bypass ignition system what would happen if you lost the sync signal but still had rpm signal. would it long crank and start or complete no start?
Love your class, dam 13 years ago I had a spine😂😂😂😂 my wife ripes it out my ass and let's the dogs chew on it and slides it back in before I wake up😂😂😂😂keep up the good work ❤
Have you ever came across having to swap distributor when changing engine due to the new engine not having a crank sensor? I have a 95 Blazer and yhe old engine had crank sensor. Tbe replacement engine doesn't. Please help. I swapped the heads and CPI already to the new engine.
No problem, and thank you
after looking at the diagram. I don't think it can be done. you cannot interrupt ICM power or ground, you will lose your input to the PCM for injection. The only option is the EST line you mentioned but I think the ICM will still fire the coils in "module mode" with an EST line fault. If the coils where not mounted on top of the ICM it would be a different story.
hey paul if you were to do a by-pass test with a ''FUSED'' jumper wire and lets say we put a low amp fuse in the jumper like a 3 or 5 amp fuse, if you got the polarity wrong would you still cook the driver, or would the fuse blow and save the circuit??
My old distributor has a ECM connection however I replaced it with a new one and there is no ECM connection . So the question is what do i do with the ecm wire that connects to the distributor
@chetsjug You need to watch Part 2, sorry I didn't label it that way. Here is the name of the video "1991 Buick Century 3300 Shorted Injectors" this is what was wrong with this car and it sounds like this could be your problem.
Interesting... So... I have a 1976 cj7 jeep with 258 engine and recently installed a gm 4.3l rebuilt tbi unit with ecm on it.. It starts and runs but has check engine light on.. Shows codes 42 and 43... These are for the spark control, which I haven't installed.. What is the best way and most economical to install in a upgraded ignition system in a cj7 jeep that the gm ecm will be able to control the timing? (the throttle body is for gm models 1987-1991 with 4.3l v6) :)
by the way, I have the bypass GM system
Hi Paul, what is the point of firing the coil from the CKP if the ECU / Injectors are not at the party. Is this to clear out the cylinders of residue or something during crank? regards Mike
You mentioned that using bidirectional control, you can fire 🔥 a Chrysler computer. How on the scanner would you do that ?
lol, never heard of that. don't mess with the EST line, you'll just set a DTC. The module will still control spark without the EST signal. what is your ignition set up? is it a waste spark? or is this a distributor engine?
so if the plugs have fire and the fuel pump whirrs but doesnt pulse the injectors in the throttle body what should we do next
You most likely have shorted injectors. Watch my videos on GM shorted injectors. I have three of them up. A quick test for this is to unplug your injectors one at a time and see if the car starts. IF it does then you found your problem. Keep in mind though that you may have more than one injector shorted. In fact the last vette I did had 5 out of 8 injectors shorted.
The only sensor I didn't replace is TPS. I have a cardone select distributor. NEW. My 89 s10 pickup throws a code 25 even though I replaced the IAT. I have a harbor freight timing light. Timing mark moves back and fourth a couple degee and engine idles fine. It's when you drive the engine holds back. When it reaches operating temps the engine wants to stall when coming to a stop. Can the red brick force the truck to run right. Is that a bidirectional scanner?
disconnect the EGR vacuum hose and drive it, see what it does. My guess is your EGR is sticking open, causing the rough idle and almost stall. This will also heat the intake to a point of setting an IAT code
could be a Fuel Pump going weak/ to Bad .check your fuel pressure and Fuel Filters might be plugging up.
HI, Where do u get such diagram, when i see All data i dont see such good diagram, do you get it from manufacturer or mitchell. please advies
Very good video! Very detailed
Hi Paul I have question 95 ram 2500 v10 no spark. this PCM need Crank and Cam sensor for spark, so PCM to ICM to coil. so should I have 2 pulse from PCM to ICM?.. From PCM have two Ignition Module wires to ICM key on 5V,, Cranking only one pulse the another drop to 0V..
I got a 98 Deville same concept but a V8 how would I keep my injectors going but shut off ignition by a push button switch? Would it be the EST wire? Its for my flame thrower kit. Its not working by killing the 12v to the ICM because the pcm is stopping the injectors.
great video, where can I get this diagram that you are using ?
Here is a DIY version of what I use eautorepair.adtrk.biz/?a=10817&c=24&p=r&s1=
You can pay for access to a single car, for a month, for $20
Ran into a problem today. 2005 Trailblazer no crank/no start. Checked ignition switch and found it wasn't getting correct voltage. Replaced ignition switch and have good voltage. But now passlock is on and still won't crank/start. I understand on this vehicle the PCM controls the starter signal and disabling the fuel pump relay. Hence why i don't get any signal to the starter when cranking. Also now i have a Theft Deterent code P1631. Where do i start to diagnose this? Would really appreciate your inputs. Thanks!
Leave the key on for 10 minutes (up to three separate times) for the pass lock system to relearn. Once the theft light stops blinking, it has relearned
go to youtube there is a 3 set precedure steps to relearn the ignition system it will take about 32 minutes or so. be patient .
STEP(1)
turn key on like your going to start the engine up release the key let it stay in run postion For 10 minutes then security light should stop flashing
turn ignition in the off postion do not remove the key at all wait 30 seconds in the off position,
STEP(2)
now try to start again let go let it stay in the run postion another 10 minutes security light in dash will stop flashing if not not worry turn ignition off wait 30 seconds again in the off postion. DO NOT REMOVE THE KEY
STEP (3)
turn key on like your going to start the engine up release the key let it stay in run postion For 10 minutes then security light should stop flashing
turn the ignition in the off postion do not remove the key at all wait 30 seconds in the off position,
STEP (4) START THE CAR . NOW YOUR PROGRAMED IN AND READY TO GO!!!
other info.
if not start then try the 1-4 steps again.
if not work then , then you have a faulty Ingnition Switch.
REPLACE A.S.A.P . there is no bypassing the theft system till it reads in the code # from the key , key code number is from 1 digit to 2 digit code starting with #1 through 15 there are only 15 numbers thats it for a chip key on all gm , but through the ignition to have the code placed back in the on board computer . once you are able to start the car.
then you can put in a bypass . 20a on and off toggle switch under the dash requires snipping 1 wire out of the 3 coming off the front side center of the ingnition switch sensor white yellow and black wires most comon on all GM made vehicles. the yellow is the one you would snip then run each end of the single yellow to the switch.just like hooking up a light switch in your house to turn on your kitchen or bathroom light and walla .now you can disarm the security theft or enable it by using the on and off toggle switch. simple and easy bypass fix. again i repeat can only do this after you relearn the key and ignition to start the vehicle first. have a nice day.
having issue with 2002 buick century no crank no start I took the resister out the key and place it directly on the wire plug at the bottom but still no crank no start I notice when I turn the ignition to start position it shuts off the ignition lights and turns back on when I relize the start position
if you were do do that while cranking it would fire correct?
Paul, on thie design is it possible to have spark during cranking and to have something wrong with the ecm and still have a no spark no start? Is it common?
Mr Danner would this also apply to older gm models I have an 89 k2500 with a 5.7l and when est wire is unplugged for ignition timing setting, runs ok,
I have voltage on signal from ICM once engine is running I have no voltage out put from pcm on the EST bypass wire, is it safe to say I may have a bad pcm, I have checked all powers and grounds and all good did I miss something
Yes, it is essentially the same system. Just remember that the ECM may force "module mode" with an EST fault. This is done by shutting down the voltage on the bypass wire. You could still have a bad module cause this condition.
Thank you Mr. Danner for taking time to answer my question. Cant wait for your next video
I have a 89 chevy celebrity 2.8mpfi. Is the wiring schematic same as a 3.1 in like the luminas? Im fighting an issue with my 2.8 i have fuel i have spark my fuel rail is about 45psi car just wont fire.
we need to check these injectors for a shorting condition, watch part 2 of this series!! We get into the injectors I believe and they are shorted!
@@ScannerDanner will do that was my plan to do so tonight. I removed dash from the car and it ran going in shop. Then after pulled dash went to start and she wouldnt no longer. So im stumped and dont wanna junk car
@ chetsjug Stalled once a wk, then 3 times a wk, no reason. Cold, Hot, Load, Idle. It would go days in between. Each time it would start right back up. It went 2 or 3 months like this. The last day on the road it died a few miles from my house. I took another car up and drove the Buick home. It was really bad, dying every few miles. Had to push it out of several intersections. Letting it cool helped a tad, but not much. Except for the 2-15 min. runs, it's just 1-30 sec. run time.
Great vid! Do you have anything on bypassing / troubleshooting PATs on Ford Mondeo (Ford)?
Will a false or weak fuel pump cause this either
Hey paul ive vie got an 89 mustang. When I look at my pip wire on my scope the top right corner of the square wave is cut off. Is this normal? When I unplug the spout connector the square wave comes back to normal. I don't understand why this is happening and I thought it was causing a poor idle issue. Any idea why my signal waveform would be changing like this. Thanks! Love all your videos
It is normal for the pip signal to do just add you described, however those "cut outs" should be even and uniform. Does it run better with the spout unplugged? (It will not rev as well due to minimal timing advance)
Ok thanks Paul! Cut outs are even and uniform. Runs the same with spout unplugged.
Car idles ok but just sounds a little off maybe a misfire. I will be checking secondary waveform soon. Injector balance looks good. Everything else I could think of checks out ok.
Staci Haskowitz
Okay cool, then you're okay with the PIP circuit. Keep looking :) I agree, secondary ignition waveforms would help. Maybe a compression test.
Will do! Compression better be good engine was rebuilt last month. Waiting on compression gauge in the mail. Also is the wise secondary ignition probe compatible with snap on scanners? Or just pico