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.