Engine/Transmission (1998.5 - 2002) Part # ?

[Nyoest]

Could anyone give the part number for fuel pressure relief valve on the VP44? I can never get this search thing down... ... ...


TIA

 

[ARoss]

On my 99 the part number is 3941156. I just installed it and my fuel pressure problems are gone! I wouldn't be surprized that this has been the cause of many an LP issue. $25 from Cummins beats having to part with $$$ for a new LP!

 

[Nyoest]

Thank you very much! I just did the Vulcan line kit with a new pump a month ago and at idle I have 7 psi, 60 mph pulling a hill I have 12! It just cant be the lift pump this soon with this setup.

 

[ARoss]

I was having the same problem. If I sat at idle I would see 10 or less. As soon as I gave her some throttle, the gauge jumped back up to 13. Since the install, rock solid PSI. I had gone through the entire fuel system before trying this. Hope you're as successful as I.

 

[JKinney]

I thought the relief valve was inside of the vp44? can some one explain the replacement procedures?

 

[ARoss]

The check valve is part of the banjo fitting that retains the fuel return line to the VP. If you examine the existing one, you'll see that there's a ball bearing showing on the hex head end of the banjo. When you remove the banjo, you'll see a spring and smaller ball bearing inside. This spring can weaken and cause the check valve to malfunction. I'm not exactly sure which pressure it regulates (I believe it's the internal pressure of the VP), but if it's not working correctly it can cause your fuel pressure to take a dive. Maybe one of the diesel gurus will chime in with a more complexed description of how it works ... hope you got the gist!