More Headaches From The VP Truck
 

Ok I've been having trouble with my '02, with all the current mods in sig and before any of them the truck seems to defuel about 2700. it will continue to pull but just barely to 3000 were the tranny shifts and it takes off again, pulls very well down low. I have changed map sensor, IAT, Checked the APPS with scan tool, shows perfect, had the truck flashed at dodge, and I've swaped from a truck that fuels to 3300 the PCM, ECM. still wont go. the VP and LP were replaced a week before I bought the truck, first think I did was put gauges on it and bone stock it would go to 0psi on fuel, so fass 150 went in, but I did drive it for 3 weeks before I found this problem, would that be enough to weaken the VP so it would not fuel up high. I dont mind putting a HRVP in if thats what the problem is but I cant get any VP death codes out of it, and would like to get this figured out before I throw anymore parts at it. anybody got any ideas?

I wouldn't change the pump yet, personally. It's just to much money until your sure. It's not out of the ordinary for a pump to be bad and not throw any codes, can't explain why but it happens all the time. As far as what it takes to kill a pump, it's a total crapshoot. I put over 3000 miles on my original IP with no LP working at all and it still ran fine for another year afterwards and some die right off the bat when the LP goes bad.

If the VP were bad I think you would have many more problems then just defueling. I've never heard of defueling being an issue with a bad pump either. No power is common complaint and lost fuel mileage. I would say this is probably a wastegate or computer problem.

Have you tried running the truck stock? What kinda boost and EGT's are you seeing while this is going on?

:pca1:

see if you can't get a drag comp box on it...then see what happens.

Oh yeah, waste gate is hooked, and the truck has done it since I owned it, and it was stock when I bought it, boost falls from 22-23 to 14-16 at about 2700, but I have done boost leak test and I can spool it and hold it as long as I want on the brakes. I have never been able to get temps above 1100, even when the boost falls off, so that would tell me it is a defuel issue, right? I have also added grounds and cleaned all existing connections of every type. As for the drag comp, why will a stock truck fuel to 3300, and mine wont no matter what I try, even with the ECM, and PCM out of the stock truck, and all conceivable combos on the comp and smarty. The only real reason I was thinking vp is just the fact that I've done everything else I can think of. I appreciate everybody's thoughts on this, cause its about to drive me nuckin' futs.

I don't really remember on the vp trucks...but maybe try an apps reset...I know on my old 91 sometimes the throttle shaft will slip and you don't get wide open when you step on it. but thats mechanical.

I agree with Phil............................ amazing huh :deal:

Lets start from the beginning. Was the truck modded when you bought it? If not then that rules out a lot of things that its not. I would try resetting the apps as a 1st step. If that doesn't take care of it, then its an ecm or Vp issue. It's not uncommon for a Vp to be bad out of the box. Were, who replaced the vp and lp?

Isn't a stock truck supposed to defuel at 2700 rpm? I know 98.5, my buddy's '01, and his brother's '02 do. That is, until Edge, Smarty, and TST get involved. :rock:

Truck was bone stock when purchased, APPS has been reset many times and checked by scan tool and swaped from properly fueling truck.Pump was put in by dodge house, it is a reman. What does the drag comp do that the smarty comp stack wont.