2001 Tahoe, Cranks no start, no spark - SOLVED

[Firebirdracer82]

I have a newly acquired 2001 Tahoe with the 5.3 (standard)

When getting the truck, I switched the relays in the fuse box for the pump, and the Tahoe started. I almost didn't buy it, but I did.

Then, when it was time to drive it home, it made it around the block a couple of times then died idling. It did not restart.

I had the vehicle towed back and got to work, thinking it would be easy.

It started briefly when it got off the tow truck, then would not start again.

New battery has been added.

What has been done so far:

Fuel pressure tested at the shredder valve - 50psi consistently. Holds pressure.

Spark - tested with in-line tester - No spark. Tried using starting fluid, no fire.

All coil packs have 12v and ground. Ground tested to battery and to block. Still, I spliced in a jumper ground just to be sure. Still no spark on any coil.

Upon inspection, it appears that the Crankshaft Position Sensor has been replaced (unconfirmed).

I do not have a scan tool, but I do have a multimeter and test light as well.

I am beginning to think the PCM is bad or there is some other problem out there, but it if was, it would not have started I assume, at least initially.

What should be my next steps?

Thank you all!

 

[Jimmyy]

50 PSI is good. Hopefully someone will chime in on how to test the crank position sensor. Being replaced doesn't mean it good especially with all the cheap parts online. I'm not much help but someone will have an idea.

 

[Jimmyy]

l'm not sure if it should but does your tachometer show rpm's when cranking?

 

[Firebirdracer82]

50 PSI is good. Hopefully someone will chime in on how to test the crank position sensor. Being replaced doesn't mean it good especially with all the cheap parts online. I'm not much help but someone will have an idea.

Thanks Jimmy, I’m normally great at these things but I’m pretty stumped myself. I just don’t know what would cause an intermittent spark problem when it started and died after bouncing around on the tow truck.

I was hoping it was a ground problem but the black wires to the plugs all show continuity with ground

 

[Firebirdracer82]

l'm not sure if it should but does your tachometer show rpm's when cranking?

It doesn’t. Most of the videos I watched don’t have the tach bouncing when it wont start and don’t have a scan tool to check in real time.

 

[Firebirdracer82]

I can also make an absolute promise that if this gets fixed I’ll post the solution. I’ve just gone through too many threads that did not post the answer.

 

[jfoj]

I can also make an absolute promise that if this gets fixed I’ll post the solution. I’ve just gone through too many threads that did not post the answer.

These years have problems with their Anti Theft/Key system. Many people put a resistor in to bypass the Anti Theft system. Search around the web and YouTube University to see of you can find something about adding a resistor to bypass the key detection for the Anti Theft system.

But then the Mods will also move this to the proper section rather than the 2021+ section.

 

[Firebirdracer82]

These years have problems with their Anti Theft/Key system. Many people put a resistor in to bypass the Anti Theft system. Search around the web and YouTube University to see of you can find something about adding a resistor to bypass the key detection for the Anti Theft system.

But then the Mods will also move this to the proper section rather than the 2021+ section.

Crud did not realize I’m in the wrong section. Will see about that possibility for the antitheft bypass!

 

[viven44]

You are getting no spark, that it the problem. The anti-theft could certainly be it...

Start with the basics
- Ensure all the fuses and circuits that are responsible for spark are good

Would be good to print the wiring diagrams, and probe all the circuits and confirm voltage when Key is in RUN. Glancing at the wiring diagram there are a number of fuses/circuits that need to function to get spark to the injectors.

Check the output of all of the fuses below with Key in Run (not start/crank, just run), and ensure you are getting 12V

 

[Firebirdracer82]

De

You are getting no spark, that it the problem. The anti-theft could certainly be it...

Start with the basics
- Ensure all the fuses and circuits that are responsible for spark are good

Would be good to print the wiring diagrams, and probe all the circuits and confirm voltage when Key is in RUN. Glancing at the wiring diagram there are a number of fuses/circuits that need to function to get spark to the injectors.

Check the output of all of the fuses below with Key in Run (not start/crank, just run), and ensure you are getting 12V

View attachment 456410

Thanks and I will! It’s raining here currently so I have to wait a little bit. I checked all fuses to make sure none on the ignition circuit were blown but I have not yet checked to make sure they have power. As there’s power on the pink wire on the coil packs I’m hoping it’s got sufficient power.

 

[jfoj]

I think these chassis also had problematic ignition switches as well.

My 2005 almost always cranks no start on the first attempt, this is common problem that shows up later in life, initially it begins about every 10-20 start attempt, then finally gets to the 50/50 situation. Always starts on 2nd crank attempt if it does not start on first attempt. Many owners have replaced everything known to many and never figure out. I believe it is a problem with the key detection. On a 20+ year old truck/SUV a resistor is fine IMHO if it works.

 

[Firebirdracer82]

I finally found my code reader. It appears I have two stored codes for crankshaft position sensor circuit. P0335. I may go pick one up and try to replace that this evening.

 

[Fless]

I think these chassis also had problematic ignition switches as well.

My 2005 almost always cranks no start on the first attempt, this is common problem that shows up later in life, initially it begins about every 10-20 start attempt, then finally gets to the 50/50 situation. Always starts on 2nd crank attempt if it does not start on first attempt. Many owners have replaced everything known to many and never figure out. I believe it is a problem with the key detection. On a 20+ year old truck/SUV a resistor is fine IMHO if it works.

The crank-no-start then, on 2nd try, crank-start condition could be a missing cam signal, or the crank-cam correlation is off. A successful CASE relearn would rule that out as the cause. Obviously fuel pressure leakdown is another that could be in play, among others.

 

[jfoj]

The crank-no-start then, on 2nd try, crank-start condition could be a missing cam signal, or the crank-cam correlation is off. A successful CASE relearn would rule that out as the cause. Obviously fuel pressure leakdown could also be in play.

This is a pretty well known problem in the 1999-2005 GM Truck/SUV world. I did some research and some people have replaced everything under the sun. Seems the 50/50 crank but no start will go on for a LONG time. I have been too lazy to really dig into it. May get into once I get some things done on the 2024 Yukon.

I know if is not fuel pressure leak down. And I am pretty sure cam and crank sensors are not the problem. As mentioned, I did a lot of research and decided if it ever hard fails, I will be able to find the exact problem pretty quickly!

 

[viven44]

I think these chassis also had problematic ignition switches as well.

Yep an ignition switch could do that.... there are a number of circuits that are typically getting power from the ignition switch.

A few months ago, my 78 quit in the middle of the road on the way back from work. No spark. Swapped with a cheap spark ignition module, no bueno, and my suspicion was the ignition module wasn't getting power so I used a piece of rope to keep the choke open, and used the 12V from the electric choke to get back home, lol.. when I got back home, I found that an old redneck crimp splice on the ignition switch harness wires going to the module had broken from years of vibrations/fatigue....

@Firebirdracer82 I think your approach is methodical and correct. Definitely check for 12V with key in run as well... You might want to get a cheap $25 scan tool on Amazon and see if there are any codes. Sadly, even by the late 90s/early 2000s there are a bazillion things that need to work in order to get spark at the right time.... sometimes you can get lucky and a code may be set that can help you get to the problem quicker.

Update: Nevermind I just saw you pulled up codes... good luck !

 

[viven44]

A successful CASE relearn would rule that out as the cause.

This comment made me go back and look at the other 2021+ post ... and even found the that this case involved the elusive P0016 code involved in the recent 6.2 recalls. Small world.

Engine shuts off while driving - SOLVED

So, just after 2 hour drive, approaching my parking my engine just shuts off, and i get a message saying restart engine. I go to restart it but it cranks and doesnt start. While waiting for the tow truck, about an hour and a half later the car starts up just fine. I drive around for a but and it...

www.tahoeyukonforum.com

 

[Firebirdracer82]

Yep an ignition switch could do that.... there are a number of circuits that are typically getting power from the ignition switch.

A few months ago, my 78 quit in the middle of the road on the way back from work. No spark. Swapped with a cheap spark ignition module, no bueno, and my suspicion was the ignition module wasn't getting power so I used a piece of rope to keep the choke open, and used the 12V from the electric choke to get back home, lol.. when I got back home, I found that an old redneck crimp splice on the ignition switch harness wires going to the module had broken from years of vibrations/fatigue....

@Firebirdracer82 I think your approach is methodical and correct. Definitely check for 12V with key in run as well... You might want to get a cheap $25 scan tool on Amazon and see if there are any codes. Sadly, even by the late 90s/early 2000s there are a bazillion things that need to work in order to get spark at the right time.... sometimes you can get lucky and a code may be set that can help you get to the problem quicker.

Update: Nevermind I just saw you pulled up codes... good luck !

I’ll hopefully update tomorrow if the part comes in. Normally would use AC delco but went with the next day TRQ option. I wish it was in a more easily accessible place.

 

[Fless]

I’ll hopefully update tomorrow if the part comes in. Normally would use AC delco but went with the next day TRQ option. I wish it was in a more easily accessible place.

Consider doing the CASE relearn after replacing either sensor. Even if the engine runs decently, a mis-correlation between the two can cause random misfires (P0300). It's a quick and easy process once the engine is at operating temp.

 

[Firebirdracer82]

Well, I promised I would update land the crank shaft position sensor fixed it for the moment! I just drove it 40 miles and running well. I may have it taken to someone with the scan tool to do the relearn process, but for the moment I want to also make sure I get the 26 gallons of gas it’s been sitting with for the past year out of it.

Thanks for all the help everyone!

 

[rockola1971]

I think these chassis also had problematic ignition switches as well.

My 2005 almost always cranks no start on the first attempt, this is common problem that shows up later in life, initially it begins about every 10-20 start attempt, then finally gets to the 50/50 situation. Always starts on 2nd crank attempt if it does not start on first attempt. Many owners have replaced everything known to many and never figure out. I believe it is a problem with the key detection. On a 20+ year old truck/SUV a resistor is fine IMHO if it works.

PASSLOCK does NOT keep an engine from starting. It shuts the engine down after about 5+ seconds if the PASSLOCK has a problem or the key is not detected.