Ck Eng Code P0251

[6speed]

I know it means fuel injection pump feedback circuit. Is it an internal pump issue or is it a electrical issue (plug) at the PCM? Rail pressure will not build above idle (5500) and when it does it is not pedal responsive, It go to maybe 10K PSI or a little more and then fall off back to idle numbers. After about 45 minutes it will build all the rail pressure it requires depending on throttle position and work fine. Replaced FCA and PRV. I am beginning to think maybe the plug at the PCM is possibly dirty, loose from when I did the PAC Brake 12-13 years ago.

 

[cerberusiam]

FCA on the CP-3 is not responding correctly, time for a new one or check the harness for connection issues or broken wires.

 

[6speed]

I replaced the FCA, I'll check the plug

 

[6speed]

What about the throttle position sensor? If the FCA does not see pedal response, could it be culprit? It seems that when the ambient temp is warm it works fine.