<E28> Ongoing Idle / Stalling Issues.. Post New FPR..

["Ron J" <ron@xxxxxxxxxxxxxxx>]

Hi All,

Well after a few days of the properly calibrated 3.0 BAR Fuel Pressure
Regulator in the car, it has started to misbehave a bit again.  Not quite a
severe as before, however still a PITA.

I was out driving the car yesterday and it would stall at low RPM.  As soon
as I turned the key again, it would start back up without an issue, and run.
There was no hesitation in the engine at all, however when coming to a stop
after getting off the gas, the cars RPM would dip down below 500, and either
stall, or almost stall, and then bounce back up to about 700 RPM, and then
go back down again, almost stall, and then even out.  If I stabbed the gas,
it would rev up, and then as soon as the pedal was released it would drop
below the 500 RPM mark and do what I described above.  The car stalled on me
a few times in traffic, so I pulled over and tightened the slack on the
throttle cable to keep the rpms up.  The car idles at about 800-900 now and
wont stall out, and sometimes idles at about 1000.  This is most likely due
to the tighter throttle cable, but slacking it off seems to cause the
stalling problem.

Another issue that is occurring is when the car starts.  It stumbles a lot,
and if you give it gas, lots of grey smoke comes out of the tailpipe, and
the car hesitates, while climbing RPM.  As soon as its warm it goes away.  I
think the problem is connected to the one above.  Possiblities might be a
leaking cold start valve as someone suggested earlier.

The car is going in for a diagnostic tommorrow at a trusted wrench that I
know, since there is way too much snow up here, and I dont have all the
tools to do it myself.

The car has a New Dealer bought Fuel Pressure Regulator, new Idle Air
Control Valve, both seem to be working fine.  The bellows has no cracks in
it, and I have hunted around for a vacuum leak in all the hoses with no
luck, or unluck as one might see it.

There is also the issue of the broken white wire on the O2 sensor, that
might be contributing to the issue..

Any suggestions would be great

Cheers
Ron J
85 535i
73 911s 2.7

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