Im working on my buddies 97 F350 flatbed, 242k. Was originally an automatic and somebody replaced it with a ZF5. Very underpowered cold, barely does 20MPH. Exhaust backpressure valve issue? When it starts, the engine revs up and down between 500-1100 rpm and wont stop this untill you tap the throttle. Once warm runs OK, has excellent off idle and low rpm power, but after that it just flattens out and does not have near the power it should above 2000RPM. Underboost maybe? He took it to a Ford dealer to orginally have diagnosed and they came up with a list of things which not all I can believe, they claim the turbo housing is cracked, has low compression on three cylinders, three bad injectors, and bad glow plugs. I looked over the turbo and saw nothing that even resembled a crack, when it wants to run good i definatly can't agree with low compression claim or that 3 injectors are bad, I would believe one or maybe two, and I'm sure it does need glow plugs. ICP and IPR readings all look fine. Tommorow I will be doing a injector buzz test and a cylinder contribution test. What I'm wondering is if any of you have had similar startup issues, with it reving up like that and wont stop untill you tap the throttle and because someone swapped trannsmissions and not ECMs if the stack of automatic trannsmission codes present are affecting any of these symptoms? Any help or suggestions would be greatly appreciated!!

 

This is absolutly just a guess...... but I think you answered your own question.I think you could check the ECM's at an aftermarket supplier and if they're different numbers (probably are)that could be the whole deal because it does make a big diffence in gas jobs.

 

I have heard that if you don't do something with the wiring that you will get a lope idle. I will PM you a link cause I think the mod will take it out of my post. It for a thread at the other forum.

 

The PCM is different from an auto to a manual. I'd start there.