Re. Strange cold start on 84 4000 quattro

[Ben Swann]

Steve,  

The engine is either CIS or CIS-E - that year saw both versions, but both systems have
similar typical liklihood of vacuum leaks. 

I didn't want to get into details with my original reply.  Although I partly agree with
Huw that it may be a sensor causing this problem, odds are greater that there is a
vacuum leak.  It is also easier to see, hear, smell, sense an air leak allowing one to
rule in or out as an obvious problem.  I think it is also a good place to start on
sorting out the engine and becoming more familiar with it.

Yes it is old news for folks who have owned many variations of the 4kQ/CGT - at some
point these engines will likely have a failed temp sender or other electrical sensor
problem, or even broken wires.  It is more likely to have vacuum hose and injector seals
needing replacement.  The convoluted ISV/crank breather hose can be problematic as there
is a small orfice valve that gets clogged, or it gets mushy and collapses, is cracked
and leaky.  There are plenty of places to check for leaks and a routine air-filter
change will reveal a lot of deferred maintenance.

Therefore my suggestion is to start with the obvious and easy to fix.  It makes no sense
to start testing sensors and fuel pressures when there is a cracked ISV hose staring you
in the face.  It really is kind of confusing to tell someone who is not intimately
familiar with CIS to start checking the WUR, fuel pressures, ECU Temp Sender resistance,
and other idiosycracies  that might be a source of trouble, when there still is a lot of
basic sorting to be taken care of.  After taking care of the obvious and doing full
tuneup, if the problem still exists, then look at the more difficult stuff.

Ben

[Date: Sun, 8 Aug 2010 21:49:06 -0700
From: "urq" <urq at pacbell.net>
Subject: RE: Re. Strange cold start on 84 4000 quattro
To: <quattro at audifans.com>
Message-ID: <003101cb377e$33093700$991ba500$@net>
Content-Type: text/plain;	charset="us-ascii"

IME leaks don't reliably go away most of the time ... 

I meant to reply earlier ... I wanted to check if the '84 4kQ has CIS-E or not ... still
haven't done that ... I *think* the comment that you have an ISV means that you have
CIS-E, but I'm not sure ... 

I'm most in agreement with Huw's comments.  The first thing I'd do is to hook a fuel
pressure gauge up and see if the residual pressure is non existent.  The comment that it
fires right away after cranking a few seconds and then shutting off and attempting
restart says fuel pressure to me.  You may have more than one problem going on too ... 

Good luck!
Steve Buchholz

-----Original Message-----

Ok well pretty sure you hit the nail on the head here. I noticed a lot of oil seapgae
just beneath the X tube above the valve cover which is prone to failure. I ordered the
silicone replacement for the X & ISV tube from 034 as well as 10' of vacuum tubing. I am
going to replace it all when it arrives and check over everything with chemtool to
ensure no more leaks... 

From: benswann at verizon.net

Nothing strange about it - you have a vacuum leak (or several vaccum leaks).
>From your description, you have a massive leak.

If you don't find anything obvious, pull injectors and replace the O-ring seals.  They
are probably due for replacement anyway.

Ben


http://www.gtquattro.com/FAQ.html]