"OT: E36 328 fuel rail not holding pressure with key off"

[Jon K]

Posting this for a friend trying to trouble shoot why his E36 backfires sometimes through the intake while cranking, and takes a lot of cranking to start (megasquirt 2, but setup just like my and other cars):



Symptoms: Car has issues starting, esp after engine is warmed up. Long cranks, intake backfires indicating lean mixture. Once the car does start exhaust has dark smoke in it.

Found the fuel pressure rail holds 0 pressure after cycling the ignition on/off. I even had a helper check immediatley after the car was off and already the pressure had dropped so much not even a drop of fuel exited the schrader valve on the fuel rail!

Where in the fuel system of the car (1996 328 OBD2) will it have a check valve?

fuel pressure regulator, fuel filter, fuel pump, fuel pump assembly?

[winfred]

the fpr is by the filter at the frame rail to the left side of the tranny

[Jon K]

winfred, what part contains a check valve? Ie. what should he replace?

[winfred]

i've never really had to screw with one beyond popping in a new fpr, it's the new style unit that's just held in with a big clip, pull the clip and pry out the fpr lube up the new one and pop it in, i've never been a huge believer of the bad check valve theory, ok so the check valve craps out, after a second or two the system is pressurized and up to snuff, i think it's more one of those things that you only notice when the car is ****ing up from something else, i can't remember if that thing runs 3 or 3.5 bar, 3.5 if i had to bet