03 Loses pressure at temperature

[sdram03]

Just got on this site, was on a different site, called Michael who was very helpful and he assisted me in getting a manual. I am going to post on this site so that people may follow my issue, possibly help or I may possibly help them. 2003 Dodge diesel 2wd with a six speed. 144k on odometer. I recently installed 50 hp brand new bosch injectors, air dog 150. No tuners, but I have a Cold Air Intake and straight pipe. Recently had problems where it would die intermittenly. Check lift pump and when on the gas would lose pressure. Replaced the lift pump with the air dog. Now at around 180 degrees the rail loses pressure, significantly. Until 180 the set pressure and the rail pressure are very close and and fca appears to be working correctly. At 180 set pressure appears accurate, fca appears accurate but the rail pressure just drops. No visible fuel leaks and the air dog has constant pressure with a mechanical gauge. Relief valve is good, FCA appears good(has been replaced), cam sensor is new, no codes air cleaner is good. I am going to try to inspect some grounds, and go from there, I am sure I forgotten something so if you have any ideas pleas post the same.Thanks in advance, and thank you Michael for talking with me on the phone and access to the service manual. Artie:banghead:

[LiveOak]

Artie, Welcome to the forum! I'll have to fess right up and say that I know next to nothing about these Common Rail engines. Perhaps you have already checked but have you been able to find and capture any codes in the ECM/PCM. Something is causing the CP3 to loose pressure to the rail. I would think that would trigger a DTC code. If so, it may help guide you on the right track with your troubleshooting efforts.

[Mopar1973Man]

Just sent a Wild and Free a PM and seewhat he says about it...

[sdram03]

Last night after talking with Michael, I went back and checked lines, cleaned grounds, I pulled the filter off the airdog and reinstalled( i always thought it was louder than I had heard it was supposed to be), cleaned battery cables and checked connections. Good news is that the airdog was sucking some air, it is way quieter now. Except that now when it hits temperature the truck loses all power. If I cycle the airdog it start until it drains the rail and then start the process again. If the truck is cool it runs like a top. No visible leaks, but at temp the rail is moving the fuel somewhere. This is maddening!!!! At least the folks at Crown Royal are helping me through the tough times!! LOL I am seriously thinking the cp3 can not build pressure when it gets warmer, and that adding the airdog, and now making the airdog effiecient is making the issue more pronounced.No DTCs not even low or high fuel pressure. Thanks for the great forum and any and all help!

[Wild and Free]

I am seriously thinking the cp3 can not build pressure when it gets warmer.

I think you answered your own question. The early CR engines had a high pump and injector failure rate due to coming with 10 micron filters that have since been changed over to 7 micron.

[dorkweed]

Rail Pressure Relief Valve......RPRV. It's right on top of the rail.......about 2.5 inches tall with a fuel line coming off the top. Or one of the engine temperature sensors.........intake air, engine temp etc. To me it doesn't sound like a CP3 because everything is fine until "normal operating temps" are reached. It's gotta be a sensor IMHO!!!!

[sdram03]

Well I was just about to take it to someone with more brains than I have to see if they could figure it out. After angst, just for good measure I pulled the fuel rail completely off and retorqued everything again. Problem solved. It appears that when I tried to do it with a crows foot that the retorquing was not taking place. So when in doubt, do it the old fashioned way!!!Thanks everybody for your help. I still do not understand how temperature was related to all this, however at this point glad it is fixed.