re. Inconsistent fuel delivery

Ben Swann benswann at
Thu Nov 10 20:40:15 EST 2005


I think you have some unrelated things going on.

The idle problem sound like a bad idle switch - located at bottom of 
throttle body, which needs to be removed to replace.  You should hear a 
little click when the throttle is openes a little.  You should verify it 
goes from closed/continuous to open with a VOM.

The other sounds like a blown fuse, ignition switch feed or the load 
reduction relay.  Consulting the Bently wiring diagram would key you into 
the common failure point.  Even a bad ground could cause this.


[Date: Thu, 10 Nov 2005 13:37:51 -0600
From: "Matt Bliefernich" <bliefernich at>
Subject: Inconsistent fuel delivery
To: quattro at
Message-ID: <BAY106-F2225C777EA7C83C1F26DE6B0660 at phx.gbl>
Content-Type: text/plain; format=flowed

Patient: '86 4kcsq

Symprotms:  The car began by taking a long time to start,  I thought it
might be that fuel was draining out of the lines and needed to be pumped
back up before it would start.  Then it began to start fine and idles fine
when cold but once warmed up a little it begins to vary between 2K rpm and
the normal 900 to 1k rpm.  It will maintain the high rpms until the gas is
pumped, then it will settle down to normal for a moment and return to the
higher rpms.  This happens while driving as well to the point that while
accelerating you can feel it jump and settle under you.  Fuel Pressure
regulator?  Now yesterday on the way to work the windshield wipers, windows,
sun roof, heater blower and rear window defroster suddenly stop working.  (I
checked all the other electronic systems and they all seem fine.)

What I have done:  I checked all the fuses and relays and when I pulled the
Fuel Pump Relay it literally fell apart in my hands.  I got a new relay and
now the other electronic systems are working again with these few quirks:
Emergency flashers are on when the switch is off and off when the switch is
on,  dash lights no longer work, intermittent wipers no longer work nor do
they return to rest when the control is turned off.

Questions:  Could the fuel problems be the Fuel Pressure Regulator and could
that be being caused by the electrical problems?  Any other ideas on the
electrical problems?  Is there something I am overlooking checking out?  Any
help would be greatly appreciated.

Matt Bliefernich
'86 4kcsq
'03 A4tq] 

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