Fuel Pressure Problem?

["Gregory Ott" <ottg001@xxxxxxxxxxxxx>]

Hello all.  I am about to drop some money for a new fuel pump for my 89 325i
and I wanted to bounce my diagnosis off you all before I did.
Initially, car was difficult to start occasionally.  It seemed at first like
it was only after it sat for some time (1 hour or more), but it was not
consistent.  If I cranked the car over for about 5 seconds a couple of
times, it would eventually fire up.  I thought it may be a fuel problem.  I
checked the fuel pressure both at the fuel rail, the pump with the engine
off and the pump running and it was OK.  Initially, the pressure did not
hold at the rail when I secured the pump, but I found a small leak in my
test rig and I thought it was causing the loss.  When I checked it again, it
held.  With the engine running, the fuel pressure was 35psi, about 8 psi
low.( I could get it to go up if I pinched off the return line) Although I
did not think this was causing the starting problem, I replaced the
regulator.  Did not fix the problem.  I have concluded that the check valve
in the fuel pump is probably intermittently sticking open and the loss of
hold pressure I first saw was due to it.  What do you all think?  Thanks in
advance.

Gregg (ottg001@domain.elided)
89 325i
99 323ic

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