Truck dying

[jackel1959]

Today while backing our 5th wheel into the driveway, the truck kept dying on me. I finally got the trailer parked and immediately changed the CPS thinking that was the culprit. But the truck continues to die when it is under a load and only seems to be doing it in reverse I can duplicate the problem by standing on the brake, putting the transmission in reverse and when I hit 15-1800 RPM, the engine just dies out. It will start right up again and run fine. There are no codes being thrown so at this point I am looking for any suggestions as to what the problem might be. This is a 2002 7.3L with Auto transmission. Thanks in advance.
Jack

 

[Frankenstien]

Picked up your response off of the RV forum, apparently there was a wire that had chaffed, and as you put the truck in reverse that would cause the engine to shift a bit, allowing the chaffed wire to short on a bolt under the air intake tube.

 

[JLDickmon]

did you check the transmission fluid level?

 

[iracemine]

wat?

 

[DaveBen]

What, not wat.

Dave

 

[JLDickmon]

mine dies when I shift from a drive gear to reverse if the transmission fluid level is low.. (I mean REAL low, like three or more quarts... gotta fix THAT leak, too...)

I gotta ask my buddy Joe (the trans rebuilder) why this happens, but I'd say somewhow the fluid level affects the flow in the valve body and solenoids..

 

[Frankenstien]

Jakel took it to a dealer, they had found a chaffed wire, taped, tagged and repaired. He's up and moving now.

 

[JLDickmon]

I hate chafing...

 

[jackel1959]

Hey all,
Here is an update on what all happened when I took the truck to the dealer to diagnose and fix the problem I was having:
6/2/09 UPDATE: When I dropped off the truck yesterday the problem could not be duplicated. They spent most of yesterday trying to duplicate the problem and get the computer to throw a code. Never happened. I asked them to drop the transmission pan and check for debris then power flush and refill. Everything looked good from the fluid to no debris in the pan I picked up the truck this afternoon, checked it at the dealer and it seemed fine. Got it home 45 minutes later, threw it in reverse and power braked it and at 1300 RPM it stalled out. Right back to the dealer I went where the senior diesel tech met me when I arrived. After scanning for codes (there were none) he was able to duplicate the problem several different times and he is pretty certain it is not a tranny problem. He is convinced it is a chafed wire somewhere grounding when the engine is torquing over. He did grab and wiggle a few harnesses on the driver's side in the engine compartment and the shock tower and the problem did go away. He will try to locate the bad wire or harness tomorrow and replace it. Right now I guess I can drive the truck as long as I don't have to back the trailer. More to follow.

6/3/09 UPDATE/CONCLUSION: And now, for the rest of the story; I got the truck back from the dealer today and it turns out it was a chafed wire in the main engine wiring harness. The wire had chafed on a bolt under the air intake tube and actually polished the bolt pretty good where it had been rubbing. Once he located the bad wire he could pretty much make the truck stall at will. He explained that particular wire carries voltage to a number of relays for the entire engine so when it shorted out it just shut down. He repaired the wire, re-wrapped the harness and placed wire shielding to prevent it from occurring again. So far so good The other good news is that the repair was covered under my extended warranty. Thanks to all for your inputs, suggestions and support.

Jack

 

[DaveBen]

Good to here that you got it fixed.

Dave