II 85% CP3 Losing RP.

[Dozerdog74]

I was getting my truck tuned the other day and I have some questions. The truck has an II CP3 (85% over), Extrude Hone 60% over injectors, DP S468 charger, built trans, intercooler, lift pump, etc. The truck started losing rail pressure on the dyno at 694hp so thats where we stopped. This doesnt sound right to me. If this pump is what it says it is it should make more then this. The truck does have the same AD 2 filters on it, it had when I bought it, could they cause the loss in RP? I know these pumps have a bad rap but isnt that usually right out of the gate? This pump is 4 years old, give or take. I have been monitoring my rail pressure and the Desired is real close to actual (Edge CTS). Any guesses, Thanks!!

 

[WisconsinHick1]

How many miles have you put on it since the AD 2 install?

 

[SmithLBZ]

I would start with the problem being II

 

[Dozerdog74]

Everything that is done to the truck, was done when I bought it. I agree Smith, not an II fan but it is what it is until I can save up my pennies to swap it out.

 

[Xternal]

Very good chance filters need changed

 

[diesel-max]

Not sure when you bought it but to start with the filters is the cheapest,easiest...Id try that.

 

[Harbin_22]

Need a low pressure fuel gauge. My AD165 with stock pick up, did over 900 many times on the same dyno and in never lost pressure with dual stock pumps and 60%

 

[plowboy_lbz]

I would start with filters. Next you need to check your lift pump pressure at idle and wot. Yes II pumps are junk. Very good chance it could be shot.