I have a 2007 5.9 that I need help with. I was driving home from camping pulling my camper and all of a sudden it started running really rough, I was able to limp home, and then took it to a shop in town. they said I had a bad injector, they replaced it. It ran ok for 2 days and then started running rough again.


I got the truck home pulled all the injectors cleaned them(they did have a little carbon on the tips) installed a new injector wiring harness and now the truck will start and run for about 5 minute then start running rough and die.


I borrowed a scanner that allowed us to see fuel pressure and when we first started the truck(Cold) we had about 6500 psi the longer the truck ran the lower the pressure got until after about 5 minute the pressure was at 2700 and the truck died again.


What do I try next?

 

More info, I took the FCA out and I did not hear anything when I shock it?? I took the one out of my sons truck, could not hear anything when I shock it either, and installed it on my truck and it does the same thing.

 

Have you checked the output of the transfer pump

 

I have not check that yet, what is the best way to do that?

 

Procedure for testing CP3 pump

 

Had same issue, spent a bunch swapping stuff to no avail, re torqued injectors and problem solved, took about an hour and cost nothing but a couple of beers :-)