Engine/Transmission (1998.5 - 2002) Problem after new VP44

[Jetson]

I put a reman VP44 from cumminsstuff.com a few months ago. It runs fine up to 2500 rpm, then power drops, boost drops 3-4 lbs, then picks back up slightly. Lift pump pressure is running 11 lbs. WOT. The lift pump doesn't seem to have a problem keeping up. I think that is because I'm not using much fuel anyway.



The reduced power seems like the drop at 2800 rpm before the pump change. It also feels like a missfiring gas engine as the power drops, picks up a little and drops again. I have been running the VA box and 275 inj. I never connected the Edge box since the pump has never felt right.



Any ideas?

 

[BrandonF]

sounds like your injection pump might be going out again. Also could try crank position sensor.....

 

[Sticks]

Do a check for codes. If none, check you connections at the CPS (Crank Position Sensor) and the main plug to the VP44.



Did you reman VP come with a warranty?

 

[Jetson]

Code check revealed an overboost code. I had not hooked the boost module back up after diagnosing the pump originally.

That explains why it always seemed to cut back at the same rpm. It went overboost and a second later cut back fuel. I hooked up the boost module and then was getting a low map sensor voltage code. Cleaned the contacts up and now it runs good, so I hooked the Edge box back up.



Now I know why I was running dead even, pulling 12,000 lbs uphill, beside a Duramax that was pulling an enclosed race car trailer. Normally all it takes is the VA box to outpull them on hills, but the computer was cutting back the fuel.