Cold start issues continue (84 4000 quattro)

[Fred Munro]

I can back up Steven's suggestion from my personal experience. I went
through a series of bad fuel pump check valves on my '86 5ktq. Typical
symptom was long cranking time, stumbling after it started, if you feathered
the throttle you could get it to rev up around 2000 RPM after which it ran
fine. If you opened the throttle too quickly the engine would die. It got to
the point where I made a fuel pressure gauge adapter that I could bolt onto
the fuel filter to see how long the system would hold residual fuel pressure
so I verify the check valve was doing its job. The Bentley has a spec on
this somewhere - FWIR it's not supposed to lose more than 5 psig over a 30
minute period, but it's been many years and 3 Audis since I had that car.
Might be worth checking out. 

HTH

Fred Munro
'97 S6 

-----Original Message-----
From: quattro-bounces at audifans.com [mailto:quattro-bounces at audifans.com] On
Behalf Of Steve Buchholz
Sent: August 11, 2010 6:13 PM
To: Scott; quattro at audifans.com
Subject: Re: Cold start issues continue (84 4000 quattro)

Let's see if I can repeat my earlier suggestion without getting spanked
again ...

I suspect that your residual fuel pressure is failing, either due to a leak
in the pump check valve or pressure regulator near the meeting head.  The
CIS system is an analog computer which uses fuel pressure as a variable, so
one of the first things I always recommend is to put a fuel pressure gauge
on the system & control pressures to make sure they are in the proper range.

Steven Buchholz (mobile)

----- Reply message -----
From: "Scott" <suffolkd at aol.com>
Date: Wed, Aug 11, 2010 1:41 pm
Subject: Cold start issues continue (84 4000 quattro)
To: <quattro at audifans.com>


If it doesn't start when cold what about the cold start injector?
and...........
Fuel Injector O-rings can be tested by spraying (FLAMABLE) liquid or 
either/starting fluid at them to see if his idle rises.

-Scott by BOSTON
quattro123.com

Message: 6
Date: Wed, 11 Aug 2010 11:23:44 -0600
From: "Ed Kellock" <ekellock at gmail.com>
Subject: RE: Cold start issues continue (84 4000 quattro)
To: "'Johnny B'" <pre95 at live.com>,  <quattro at audifans.com>
Message-ID: <785B0F29D9C045E2BCD7BBC8DB79C08D at Boonieslap>
Content-Type: text/plain;   charset="us-ascii"

Have you checked the injector seals?

Touching the gas and having the engine die sounds exactly like a too 
lean
situation.  On my 85 urq I went around and around and found that all my
injector seals were loose.  We removed each injector and just tightened 
each
seal and cured what amounted to a serious vacuum leak.  They're not all 
in
hoses.


Ed



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