Truck stalling out

Tiny
SBRENTON
  • MEMBER
  • 2004 CHEVROLET SUBURBAN
  • 5.3L
  • V8
  • AWD
  • AUTOMATIC
  • 245,000 MILES
My truck is stalling out at random times without any rhyme or reason. Fuel pump has been replaced and some wiring under the battery plate fixed from being frayed. When stalling I have measured a consistent 58 psi so I do not believe it is with the fuel system unless it is after the fact at the injectors. One thing I do notice is the check engine light does not come on when I cycle the key to the position just before starting. I believe that is telling me the PCM is not going through its initial startup sequence.

I have also had a couple problems where I cannot shift the car from park and that usually fixes itself quickly by cycling the key on and off.

Is it possible the ignition switch is causing communication issues with the PCM circuit? If not any other ideas?

I do not have any active or pending check engine codes.

appreciate any help. Thanks!
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Friday, June 23rd, 2017 AT 11:33 AM

6 Replies

Tiny
KEN
  • ADMIN
Hello,

A couple things come to mind, first is the crankshaft angle sensor which will stop the injectors from working, here is a guide to help with that.

https://www.2carpros.com/articles/crankshaft-angle-sensor-replacement

and it you may have an ignition switch going out as well.

Here are some diagrams (below) on how to change the switch out.

Please let us know what happens, we are interested to see what it is.

Cheers, Ken
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Monday, June 26th, 2017 AT 11:44 AM
Tiny
SBRENTON
  • MEMBER
Is the crankshaft angle sensor the same as the position sensor? I am not a mechanic so I dont always get all the terminology right. My following comments assumes they are one in the same.

I replaced the ignition switch a couple days ago but still have the stalling. I have not replaced the crankshaft position sensor yet. This was actually one of the things I was thinking about as well as the camshaft position sensor. I will take a shot at the crankshaft position sensor as you suggest and let you know if it solves the issue.

Hey. Actually. If memory serves me right that is right above the starter motor, correct? When starting the suburban it starts after a second or so but after firing it sounds like the starter motor spins for a few more seconds even after I release the key. Could that be an indication of the crankshaft position sensor failing?

Thanks in advance!
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Monday, June 26th, 2017 AT 1:16 PM
Tiny
KEN
  • ADMIN
Hello,

Yes, the crankshaft angle sensor is the same and its in the same location as the guide.

Here is a video of the job being done.

https://youtu.be/sKo7xRWVNqY

Please let us know what happens.

Cheers, Ken
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Tuesday, June 27th, 2017 AT 10:49 AM
Tiny
SBRENTON
  • MEMBER
OK, I did the crank sensor and that was a pain. There is near no room for that starter and laying on my back in a driveway does not help much either. Well I hope this solves the problem and will update you after I drive it a couple days with no stalling. Thanks for the advice and help.
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Tuesday, June 27th, 2017 AT 7:16 PM
Tiny
SBRENTON
  • MEMBER
OK, it stalled after this sensor change and after a few days of it working great it sat for 24 hours and now it won't start at all. I am not getting any spark at all 8 plugs using a smart tester. Juice is getting to the coils tho. I also have 55psi fuel pressure and all inspectors are pulsating the noid testers. Any other ideas?
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Tuesday, July 4th, 2017 AT 9:27 AM
Tiny
KEN
  • ADMIN
A couple things come to mind, first is an oxygen sensor that can be shorting out, please disconnect all of them and try to start it.

Here is the engine wiring diagrams (below) and some guides to help you test for power in the system

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

and

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Please run some tests and get back to us we are interested to see what it is.

Cheers, Ken
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Wednesday, July 5th, 2017 AT 2:44 PM

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