03 Dodge looses power when warm
 

Just bought an 03 Dodge 2500. Nice truck runs fine around town but at freeway speeds around 10-15 minutes after initial start will barely climb a hill at the speed limit. I put my foot in it and get very little response and if it down shifts I'm hosed (all rev and no go). After running for awhile the power does come back. Can't figure out what's happening. I've replaced the fuel filter, installed a Banks intake with Super Scoop, I've gone through the APPS reset procedure, checked my ground straps, looked for wiring harness shorts. The codes it's throwing seem to be inconsequential and probably due to the Diablo Predator programmer. That was until I just checked them again. It was throwing P0633, 0602, 2509, and still is... but just now it threw a new more ominous code 0251 (Fuel Injection Pump Mechanical Failure Fuel Valve Feedback Circuit) It still runs the same as I mentioned above so it's not like a complete mechanical failure - Does anyone have any ideas about what's going on?

What does your fuel pressure look like?

I have no way of determining what my fuel pressure is. It feels like I probably don't have the pressure I'm supposed to have but why would that change after it initially warms up and then comes back to life a little while later? I have the in tank lift pump and there is a yellow paint mark on the cp3... the kind you see from salvage yard parts. I just don't understand why the inconsistancy in the power.

Well you need to get a fuel pressure gauge. I am willing to bet you are not getting enough fuel.

Yea... I'll need something I can read from the drivers seat. Do you know a good guage that isn't too expensive?

P0602 Checksum Error

P0251 CP3 Pump Regulator Control

This is indicative of an FCA failure, its the only part on the rear of the CP-3 that has a wiring harness to it.

Obviusly, checking fuel pressure is a good idea to rule that out. Just get an oil pressure gauge from the local car parts store and temp mount it if you don't want to drop the bucks on gauges. Otherwise The EV2 ISSPRO gauges are some of the best.

I had the same issue , i have a 03 2500 and on long highway trips is would act up just as you describe . What my problem was at normal pedal the FRP was fine but when i would get a little aggressive the FRP would drop to 4,500 psi so my lift pump was going out so i put a fass 95 water / fuel system in and fixed the problem ..:tu: but your lift pump feeds your cp3 so be ready to change both . I know it only a matter of time before i replace my CP3 . I found the fass for $575 . Good luck :tu:

OK - I've done alot of things since I was on here last and it's still guttless. I've installed a new FCA - nothing, I've installed a new Air Dog II so plenty of pressure to the CP3 now - nothing, The Offroad shop I've been sending it to said "99.9% sure that the rail pressure relief valve is shot" - capped the relief valve - still nothing, I've adjusted the valves - nothing, I found out that my Predator will read the real time rail pressure and boost - looks like there's plenty of pressure and boost. It will puff a little black smoke on take off but then nothing. It just seems like the timing is off or something. It's only throwing a 0602 and 0633 but I'm running the "Performance" Predator tune which usually throws them. I'm at a loss as to what it might be now. My mechanic is scratching his head as well. Any thoughts?

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Also, when it gets up to operating temperature it stalls constantly even while rolling if I let off the throttle - had to restart it a dozen times this morning - it usually works through this issue and runs without stalling the rest of the day - but still no power.

torque your fuel tube nuts, they have loosened up

But wouldn't that cause a hard start issue as well? My truck starts just fine... even right after it stalls.