I'm posting this for a friend of mine. He just called me and said his 03 just died on him. The CP3 seems to be getting fuel. He has an airdog fuel pump and it seems to be working fine. He said it will start but it takes a lot of cranking to get it to do so. It will run but when he hits the accelerator the truck dies immediately. He was wondering if it may be the CP3 or possibly the rail pressure relief valve. He disconnected the banjo bolt from the top of the relief valve and it has fuel downstream of the relief valve. Is this normal?

I figure someone here can offer a suggestion.

thanks
Dave

 

Is he throwing any codes? So many possibilities, FCA, APPS.... there will be fuel in the line off the rail relief valve(return line).

 

Sorry, I forgot to mention that the truck is not showing any codes.

Dave

 

I believe the FCA gets replaced far too often, when it is in perfectly good condition. Have him unplug the FCA, then see if it will start and rev, if it will not start with it unplugged, have him start it and then unplug it.

It's going to rattle like hell, and do not operate it this way, just a test. It will probably throw a code, though not always.