Onsiteservice
09-19-2009, 11:35 AM
1994 Chevy K3500 4X4 6.5 ltr
Long story short, customer intial complaint that it would start and die 3 times in the morn then run most of the day. Second complaint, turning corners intermittant die issue.
We informed the customer we could look at but it was a week out. Customer decided to fix on his OWN.....
We speculate that the truck only needed a new oil pressure sensor (intial two complaints) seeing on how when we finally got the basket case the fuel pump would not run after the unit started.
So customer somehow diagnosed it as an injection pump (electronic). He and some of his shadetree mechanic buds installed not knowing the pump had to be timed....yee haw already. After the botched pump install and it did not run they decided to drop the tank and install a new pickup, fuel pump and lines....once again botched.....we had to drop the tank to put the float back on the new pickup....So this is what we have done...
Removed front structure and intake....timed the injection pump...oh by the way another new one...they broke the cold start seleniod off of their first new one by prying it???? Installed the pump....installed a new oil pressure sensor, installed a new fuel filter housing...the other was siliconed together...truck runs great! Until you put it in gear....truck revs in park and has nothing once it's put in gear....the throttle is working and the PCM is showing 99% @ WOT. We have ohmed all the wiring in the circuit to the stepper motor....checks OK. We wanted to have the TDC relearned to just make sure....took to the dealer...they put a new PCM in the truck...didn't fix...then the diesel tech they had finally gave up after two days.
So heres the deal....the pump timing actual and desired are good...when you un hook the stepper motor from the pump the PCM defualts to a set fuel pressure and pump timing....the truck has power when you do this....as soon as you plug the stepper motor in the injectors change pitch and it goes back to no power in gear.....anyone ever heard of this??????
Long story short, customer intial complaint that it would start and die 3 times in the morn then run most of the day. Second complaint, turning corners intermittant die issue.
We informed the customer we could look at but it was a week out. Customer decided to fix on his OWN.....
We speculate that the truck only needed a new oil pressure sensor (intial two complaints) seeing on how when we finally got the basket case the fuel pump would not run after the unit started.
So customer somehow diagnosed it as an injection pump (electronic). He and some of his shadetree mechanic buds installed not knowing the pump had to be timed....yee haw already. After the botched pump install and it did not run they decided to drop the tank and install a new pickup, fuel pump and lines....once again botched.....we had to drop the tank to put the float back on the new pickup....So this is what we have done...
Removed front structure and intake....timed the injection pump...oh by the way another new one...they broke the cold start seleniod off of their first new one by prying it???? Installed the pump....installed a new oil pressure sensor, installed a new fuel filter housing...the other was siliconed together...truck runs great! Until you put it in gear....truck revs in park and has nothing once it's put in gear....the throttle is working and the PCM is showing 99% @ WOT. We have ohmed all the wiring in the circuit to the stepper motor....checks OK. We wanted to have the TDC relearned to just make sure....took to the dealer...they put a new PCM in the truck...didn't fix...then the diesel tech they had finally gave up after two days.
So heres the deal....the pump timing actual and desired are good...when you un hook the stepper motor from the pump the PCM defualts to a set fuel pressure and pump timing....the truck has power when you do this....as soon as you plug the stepper motor in the injectors change pitch and it goes back to no power in gear.....anyone ever heard of this??????