Hard start & rough idle when cold

[pdooley]

I didn't read the whole thread and now just jumping in, but maybe can be
helpful.
For any CIS car with hard starting I would thoroughly check for vacuum leaks
before anything else.  My 5KT would hard start- turned out the Michelin man
hose was cracked.  Didn't even see it until I pulled the hose and flexed it
all different ways.
Sorry if the suggestion of vac leak was already mentioned, I deleted
previous posts.

-----Original Message-----
From: quattro-bounces at audifans.com [mailto:quattro-bounces at audifans.com] On
Behalf Of urq
Sent: Tuesday, February 09, 2010 9:17 PM
To: 'audifans'
Subject: RE: Hard start & rough idle when cold

The OXS signal isn't even monitored by the ECU until the engine warms up ...
plus you need to make sure you have a high input impedance meter to make
sure you don't change the value by reading it.  If I suspected the OXS was
the culprit I'd disconnect the sensor wire to take it out of the picture and
see what changed (if anything).  

I remember reading the list of items checked originally and it seemed pretty
comprehensive ... and I don't have that much BTDT with CIS-E.  

Steve Buchholz

-----Original Message-----
From: quattro-bounces at audifans.com [mailto:quattro-bounces at audifans.com] On
Behalf Of Bill Green
Sent: Tuesday, February 09, 2010 4:19 PM
To: audi at humanspeakers.com; 'audifans'
Subject: RE: Hard start & rough idle when cold

I just went and checked it again. I inserted my multimeter in the single
line from the sensor to the ECU. When the engine was first started it
fluctuated between .2 and 1.0 for thirty seconds or so. Then it settles down
to fluctuating between .53 and .55, After fully warming up it drops to .52
to .53, If I rev it as you suggest it momentarily drops to 4.9, Actually
replacing the sensor improved overall performance but not the starting
problem. 




-----Original Message-----
From: Huw Powell [mailto:audi at humanspeakers.com] 
Sent: Tuesday, February 09, 2010 5:25 PM
To: Bill Green; audifans
Subject: Re: Hard start & rough idle when cold

"The O2 sensor is new and reads .5v with very little fluctuation."

Then it's not reading (sorry not get to this earlier, thought of it 
while grocery shopping).  The wire from the ECU itself will read 0.5 
volts.  On a non-managed engine, the OXS will almost certainly read 
almost zero or almost one volt.  Are you sure it's plugged in properly? 
  Did this problem, um, start when you replaced it?

Try reading its output while revving the engine up and down a few times...

-- 
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/

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