BMW325 starts, sometimes then stops

bmw
325

#1

Commencing a few years ago the engine would occasionally stall after starting. Restarting usually worked. Recently the restart may fail for several trys. Some days there is no problem whatsoever. Weather has no effect. It’s sunny Northern California after all!



Once or twice while on the road the car would lose power, maybe maintain 1000 RPM as if fuel starved, and die if taken out of gear only to restart with one or more trys.



Depressing the gas pedal after the start doesn’t really seem to help. It appears the Cold Start system is working but continuous fuel seems to be the problem.



Nothing else seems to malfunction except occasionally the ABS system light goes on when starting, but not related to failure to start. Coasting and turning the key off and on again with the clutch engaged corrects this.



Wha’s wrong guys?


#2

What year 325 ?

Without knowing that info I’d hazard a guess at:

Blocked fuel filter.
Sticking (failing) fuel pressure regulator.
Failing fuel pump.

I’d start with an OBC code check. If no codes are present change the fuel filter.

If this doesn’t fix it you’ll need a fuel system pressure test.


#3
  1. The problem is intermittant thus filter doubtful.
    It either is perfect or will not keep running after starting.
    Failing fuel pump should, I’d think, show problems when car is normal.
    Again pressure check. Why intermittant?
    I was thinking of sticking relays.

#4

Ah 86 - Then I’d start with an ignition /fuel diagnosis next time it refuses to start.

A couple of known starting problems:

#2 relay faulty and not energizing. The fault could just be it needs the contacts cleaning and refitting.

Corroded battery fuse link connection.

But you really need to determine the fuel or ignition symptoms before you can advance much further.