Rough Running 90q

[DePenning, Charles [EPM/MTN]]

 Well, I think I can scratch the cat off the list as possible problems to my
poor running 90q- this morning I took the cat off at the exhaust header and
started it up- same exact behavior as before.  Plus, the cat looked really
good from the front anyway. This is driving me nuts- there are only so many
inputs to the equation to make the thing at least run decently... 

Bad OXS?
Vacuum Leak?

Any BTDTs?

Thanks for any help!

Charley

'89 90q
'84 4kq
'83 5kT




-----Original Message-----
From: TEX  TERRY,  II
To: Charles.DePenning at EmersonProcess.com
Sent: 3/19/04 8:00 AM
Subject: Re: Rough Running 90q

Hi Charles  -  I receive the digest form of the list, so little bit late
in
responding.

Did you ever get any helpful response (to your message below), or do you
still have the problem?  Since you said that you had very little
difference
(in engine running) when you pulled each spark plug lead, I would guess
that all the cylinders are firing.  This would also mean that you do not
have any clogged injectors.  The build up of the back pressure, caused
by a
clogged catalytic convertor, can definetly give the same symptoms you
are
having.  I had this happen on my '83 5kt.  I disconnected the cat,
cleaned
it out, put it back on (just for test purposes), and it made all the
difference in the world.  Due to many different items coming up, I have
not
been able to finish working on the car (think I have a faulty cold start
injector now), but hopefully I will have it back on the road this
summer.

Tex Terry, II
83 5kt sedan (non-quattro)
Franklin, PA  USA

> Message: 4
> Date: Thu, 18 Mar 2004 11:24:05 -0600
> From: "DePenning, Charles [EPM/MTN]"
> 	<Charles.DePenning at EmersonProcess.com>
> Subject: Rough Running 90q
> To: "'quattro at audifans.com'" <quattro at audifans.com>
> Message-ID:
> 
<619264F5DAF02344BC3B7F279A474245071684C8 at mxsfrcomtn1.na.emersonprocess.
com>

> 	
> Content-Type: text/plain
> 
> Hiya, I'm looking for some technical help with my '89 90q.  Here are
the
> symptoms:  Starts ok cold & warm, but runs very rough, like it is
missing
on
> one or more cylinders.  It idles ok some of the time, then devolves
into
> roughness, shaking, sputtering.  If I rev it up a bit and hold the
throttle
> at a set position, say, 2500 rpm, it smoothes right out, but getting
there
> is rough.  Driving- no power.  Moving it around my driveway is an
exercise
> in patience and lots of revs.  This happened suddenly-  I was driving
at
> highway speed and it just started this behavior and it's been this way
for a
> couple of weeks.
> Here's what I have checked:  Pulled a 4444 from ECU.  Fuel system
pressure
> great, good bleed down pressure.  Great compression for 234,000 miles,
> across all cylinders.  Plugs look good.  Pulled spark plug wires off
one
at
> a time, no discernable difference.  Air filter ok.  Pulled oil filler
cap
> off, didn't die right away, but started getting there.  Visually
checked
> vacuum system for leaks (not that that says much).  Tried the propane
torch
> vac leak detection method- no increase in idle speed noticed.
> 
> So, I've got a couple of ideas:  blocked cat, big vacuum leak that I
haven't
> found, one or more plugged injectors.  The fact that this started so
> suddenly is what is throwing me a little into the realm of blocked
something
> or ripped hose somewhere.
>   
> Whatdya think?
> 
> Thanks in advance!
> 
> Charley DePenning
> '89 90q
> '84 4kq
> '83 5kT
> 
> 
> ------------------------------
>