From digest.v7.n605 Mon Nov 17 12:48:52 1997
From: bmrfamly_at_nwlink.com (Dan, Marilyn, Phil Patzer)
Date: Mon, 17 Nov 1997 03:30:08 -0800
Subject: 535i bucking, smoking problem
The standing fuel pressure for the injection system is controlled by how
much fuel is returned to the gas tank in this recurculating type system.
When fuel pressure regulator fails to open fully, the pressure at the
injectors will rise and the engine will be forced onto a very rich diet.
Running at full speed will clear up all the symptoms. Slow running, or
Idling will result in snorting, smoking, stalling.
Continued driving will result in failure of the oxygen sensor, the
catylist and potentially a catylist fire.
I've seen the interior carpets scorched by the heat of after-burning
The pressure regulator is at the front of the fuel delivery rail on a
'87' 535i, and is quite easy to remove and replace. Use extreme caution in
removing the regulator as there can be considerable pressure behind it.
Some would advise removal of the fuel pump relay with engine idling as
this would allow the pressure to bleed down considerably prior to removal
of the regulator.
Doing this on an otherwise cold engine would be recommended. Wrapping
the regulator/fuel rail junction with lots of paper towel will reduce the
"explosive" spray of escaping gas. All common sense warnings come into
Lubricate the pre-installed O-ring well with something like vasoline, and
the O-ring will draw into place as the regulator is bolted in evenly
turning each bolt just a couple of turns at a time.
the CyberWrench 425-259-3601
from Bimmers Only http://www.nwlink.com/~bmrfamly/
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