CC Cummins Fuel Supply Problem

[hiker john]

2008 CC Inspire 360 FE with 50k miles with ISL CM 2150. Last fall drove from SoCal to OR and had no start after two months in RV park with several starts while parked. Both filters were new before trip and tank was full. Called Cummins Coburg for three hour service call...engine started and ran for 15 seconds but quit and no start. Towed to Coburg for nine hours of service and engine started and ran fine for drive home to SoCal. Techs documented low fuel pressure code and assumed that problem was fixed. Started engine weekly for four months and again no start. Bypassed water separator/filter and engine started and ran ok for another month until no start condition reoccurred. Bled air from tank supply line and engine started and ran weekly for another month. Now no start again. Cummins suspects lift pump failure....lift pump operates but fuel goes to engine with no start....I add anywhere from 1/4 cup to 1 cup fuel over each of ten lift pump cycles. Suspect fuel is going back to tank in return line. Cummins Care & Coburg somewhat helpful suggest replacing lift pump..."lift pump has check valve that may bypass fuel." CC listed Cummins Serial Number as 467 832 29 but the Maint Manual Flow Diagram page D2 shows components in different locations....shows lift pump behind ECM cover plate. RV is parked at home in Solvang about midway between Cummins Ventura and Bakersfield. Called several local diesel engine service numbers but no response yet. Any ideas? Hiker John

[Smitty77]

I'd go ahead and change the fuel filters. If you can get the primary filter cut opened, it might reveal algae bloom. If so, then get Power Services product and spike the tank to kill off the algae. (Or, see if a mobile fuel polisher might be available to clean the tanks fuel.).

Suggest if not running the coach and engine to temperature, that periodic starting/idling or even fast idling - is really not helping (And could be hurting.) the engine more then it's helping...

I do also recall reading of a fuel problem being tracked down by a mobile tech doing a temporary install of a pressure gauge between the fuel line and the Lift Pump - that could show if you have a fuel supply problem to the Lift Pump. If so, back up, and have the tech move that gauge to in front of the Primary Filter, and see if you're having a Tank Fuel Pickup Problem.

I'll follow the thread to see what other's suggest, and also as you work our way to a solution...

Best of luck,
Smitty

[Gary Wittig]

Might look into the installation of a FASS fuel system....

[hiker john]

Smitty,
I detected a fuel bypass while filling the fuel filter....after multiple cycles of boost pump operation, the filled filter would deplete various amounts, but engine would not start. Cummins Coburg had discussed fuel bypassing to the tank at the boost pump, but they never verified. Replaced boost pump and engine started and ran for a few minutes, then quit. Finally found an air ingestion point at the swivel joint at the water separator/filter. Local independent diesel tech replaced fitting and engine operates well. Spent over $2k for 3 hours road service and 6 shop hours at Cummins and they could not figure it out. All of the computers and tests do no replace good trouble-shooting technique! Thanks for sharing your experience! Hiker John

[randomledder]

Just curious if it was the fuel water separator housing with the black plastic primer pump built into it?

[Smitty77]

John - Glad it's fixed!!! And really appreciate you posting what you found, as it may help others in the future researching fuel related problems!

And that sure does not sound like a common problem, so some understanding on how it was missed by earlier tech's (NOT that that makes it any easier on the pocket book!).

Travel safe, have fun,
Smitty