help diagnosing

[blk350on20s]

Hey guys. Trying to help a buddy dignose a truck via text. Heres whats goin on. The truck would randomly shut down on the guy. He took it to a place where they scanned it and they said it wasnt reading the cam sensor. They replaced the sensor. Got a no start. They replaced the FICM and pcm and got it to fire. That is all it will do though. Just idles. If you touch the pedal it will rev but if you WOT it it will shut off. I believe he said if you put it in gear it shuts off to. Any ideas. The truck is sitting outside now. Thanks. Ryan

 

[windrunner408]

The only thing I can think of is that it probably needs a crank shaft sensor too.

 

[blk350on20s]

Thats what i suggested as well. Anything else guys?

 

[Atsah]

Throttle position assy maybe..

 

[ITUKMOR]

Does it have any aftermarket electronics installed? (ex. Edge, Bully Dog, etc...) Anything that taps into or intercepts PCM and sensor signals

 

[Mdub707]

Any smoke? Anything done recently? What's the fuel pressure? So they replaced the cam sensor and then it wouldn't start? Sounds like it didn't need a cam sensor at all. Highly doubt it needs the crankshaft sensor either.

What's ICP actual/ICP desired/IPR duty when it's cranking/running if it is. Did this just develop out of the blue or was some work done on it recently?

Did this shop do anything with the "new" PCM. I think I remember reading on here someone said they swapped a working PCM off another truck and all it does is idle, wont rev or anything.

 

[blk350on20s]

I will ask on all questions. As per electronics i think its all stock

 

[Big Angry Hillbilly]

PCM needs to be programmed to truck.

Symptoms sound typical of engine harness chafing.

How did these guys arrive at the conclusion it needed a FICM and a PCM?