ISX15 CM2250 LOW PRESSURE FUEL

[Rawze]

(06-01-2022 )Captain Donny Wrote:  Any ideas why the low pressure fuel is excessively high? Cummins spec is 145psi at high idle..

I'm at 225psi at the filter head test port. I also tried bypassing everything (cooler plate, filter and filter head) and still same readings. I jumped from my lines from the gear pump outlet to the high pressure pump inlet.

How else can I approach this problem without throwing parts at it?

you say it is a CM2250 engine...

Low pressure fuel codes are nothing at all to play around with on an common rail ISX. If the fuel pump is failing internally, it can destroy the entire engine in only a few days or so. Because of this, the first thing to do is pull the pump head off and inspect/test the guts of the fuel pump.

Also, if the pump has more than 400k miles or more than 8,000 engine hours on it then the pump needs to be pulled apart and all of its guts replaced any ways.. regardless of how they look.

-- next, is to ensure the engine passes a fuel rail leak-down test, as specified in this video ...
ref: http://rawze.com/forums/showthread.php?t...2#pid69262