losing fuel pressure on my 2011 DD15 Cascadia

Did they pull an oil sample to see if it's leaking into the crankcase somewhere? Any leaks apparent on the engine, or puddles of fuel under the truck, esp. if you can restart it then let it sit in the same spot for a while?

 

There are a few recalls. I would think if a crack could develop a leak it could also suck air and let the fuel drain back.

They all sound related to the cheap Bosch stuff. It sounds like you had that replaced? It should of been free of charge.

I'm thinking on the back side of the fuel pump at the inlet is a check valve? Not sure on that engine, just guessing. A check valve is like the finger on a straw effect. But any leak at any connection or gasket would allow air back in and allow it to drain.

I remember reading a few months back about someone's right tank not feeding and there is a yellow fuel tank transfer handle inside the DEF door under the driver's area or something like that. The transfer is irrelevant but a bad gasket or connection would allow it to suck air. Just a thought.

 

Sad,that the dealer cannot figure how to use an vacuum hand pump to diagnose....

.... Philip

 

I had trouble with my 09 cascadia it turned out to be the shut off valves under the cab the long rod on them bouncing up and down causes them to leak around the packing nut since i never use the i had them replaced with brass fittings no more valves no more troubles. As for town and country they had my truck in december spent over a week there diagnosing a elc. problem in a wiring harness I told them when I pulled in there to just replace it but I'm only a stupid trucker well over 2500$ in shop time looking for the problem they replaced the 300$ harness and who-la it's fixed I would not set foot in that place if it was the last freightliner dealer on the face of the earth I'd have it towed to the moon there nothing but a bunch of smug ***holes the next time I see the Service manager it will be in court.

 

not sure if you solved problem i had the same issue .it was the low pressure fuel pump leaking due to being worn . the last couple of services i had small amounts of metal on the primary fuel filter screen .i was told its normal guess not .. btw power came up a fair bit after fix due to the slow wearing of the pump gears i hardly noticed how much it lost over time. mileage was at 650,000 miles when it went out no codes whatsoever

 

mr sandman, we just got a problema like the one you said we lost fuel pressure for no reason , our truck start fine one day and overnigth wont start.our mechanic it says it was a plate with sensors bye the drivers side on the engine , visible , well we took tha part out went to the dealer to look for , part it was to expensibe we talk to mechanis from the dealer and they say it was the problema the fuel pressure check valve. and I ask .. how big is it ? they dont have no idea. allways they replace the complete part. well another mechanic say you guys are wasting you time ..here is you check valve . it was just a regular check valve , wich is conected to the pdf plate, not in the pdf plate no , under and is not part of the pdf platetwo hoses conect there they are fuel lines there is you fuel check valve , good luck and is like 40 dlls part. good luck.