Your Real Estate Professionals In Spain
Audifans.net: Audi Forums

www.audifans.net :: View topic - Very poor idle.
 
 Forum FAQForum FAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
View next topic
View previous topic
Post new topic   Reply to topic
Author Message
bosigran
Camped on the site



Joined: Nov 21, 2008
Posts: 473
Location: In the dark recesses of your mind. But if not there then Bath or Dubai

PostPosted: Wed Jun 27, 2012 7:00 am Reply with quote Back to top

When I was last home in March my 20v 90q developed poor idling. In fact by the time I left it wouldn't idle at all. It started with poor starting when hot with sometimes cutting out at junctions. It deteriated quickly to a point where it now cuts out when the throttle is closed when stationary and very difficult to start when hot. Methinks it may be a timing issue but I could, and more than likely will be, wrong. I'm home again on the 20th July for three weeks and would like to get this issue sorted quickly as I there are track days to be done.

Cheers all.

Steve

_________________
Present cars: 1989 90Q 20V. 2001 S8
Previous cars
1990 90E. Died a horrible death
1995 80 2.0 Sport. Hit a deer. Both car and deer written off. Kept me in venison sarnies for months tho!
1989 CQ 10V. Ebay mistake
1990 90Q 20V. Ebay bargain
AOC 1503 
View user's profile Send private message
IanW_home
Bandwidth Buster



Joined: Feb 02, 2003
Posts: 701
Location: Reading

PostPosted: Wed Jun 27, 2012 12:55 pm Reply with quote Back to top

With mine, I found idle issues had one of two causes:

1. Idle bypass screw or idle control solenoid cruddy.
2. Air leak.

Symptoms were the same hot or cold: poor idle, roughness at low engine speeds, but everything hunky dory on wide open throttle.

Poor hot starting (but OK idle) was due to leaky injectors.

Given that the ignition timing is fully electronic & non-adjustable, it would not be the first thing I checked.

Ian.
 
View user's profile Send private message Send e-mail
scotty33
UltraUser



Joined: Mar 18, 2005
Posts: 1570
Location: Gwent

PostPosted: Wed Jun 27, 2012 6:12 pm Reply with quote Back to top

It won't hurt to clean the idle screw, but I think, that this would not cause the hot starting to deteriorate, so the vac leak is more likely, look for splits on the 'michelin man hose' esp underneath. The crankcase breather hose is another likely culprit, if it has not been done?
Something like a bad ECU temp sender (2 pin white, on back face of head) or O2 sensor could be at fault. Possibly a good idea to clean the MAF sensor elements too? oil fumes from breather can contaminate them. Also check the vac feed to the fuel pressure reg is intact at both ends

_________________
Coupe 20V 1990 X 2

Passat sport tdi 2001 X 2 
View user's profile Send private message
audioc
Site OWNER



Joined: Jan 17, 2003
Posts: 12502
Location: E Bay?

PostPosted: Wed Jun 27, 2012 9:08 pm Reply with quote Back to top

check all the earth's, over and above scotty33's recommendations- I think there's one to the inlet manifold- had a similar issue years back. Bolt into the manifold connecting the earth point was missing....

if a timing issue, I would not expect it to start at all (and if that's the case, first thing I would check is the dizzy gear, unless is not plastic)

_________________
Don\'t forget: Twitter- www.twitter.com/audifansdotnet
Facebook - www.facebook.com/audifans.net
Free \"Audi\" Newsletter: http://www.audifans.net/downloads-cat6.html 
View user's profile Send private message Visit poster's website MSN Messenger
bosigran
Camped on the site



Joined: Nov 21, 2008
Posts: 473
Location: In the dark recesses of your mind. But if not there then Bath or Dubai

PostPosted: Mon Jul 02, 2012 3:45 pm Reply with quote Back to top

Thanks guys. Interesting points you have made. I'll take a look as per your recommendations and see what happens. Watch this space.

_________________
Present cars: 1989 90Q 20V. 2001 S8
Previous cars
1990 90E. Died a horrible death
1995 80 2.0 Sport. Hit a deer. Both car and deer written off. Kept me in venison sarnies for months tho!
1989 CQ 10V. Ebay mistake
1990 90Q 20V. Ebay bargain
AOC 1503 
View user's profile Send private message
Dozey
Audi Nut



Joined: Aug 22, 2011
Posts: 62

PostPosted: Wed Jul 04, 2012 8:52 am Reply with quote Back to top

I had poor idling on my coupe, changed the lamba sensor which helped Wink
 
View user's profile Send private message
bosigran
Camped on the site



Joined: Nov 21, 2008
Posts: 473
Location: In the dark recesses of your mind. But if not there then Bath or Dubai

PostPosted: Fri Jul 06, 2012 2:59 pm Reply with quote Back to top

We have a result. Got home last Tuesday and checked all the things you guys mentioned. Ripped the thing apart. No air leaks cleaned the ISV and everything else. I noticed on closing the throttle the engine speed would slow down very slowly. So I checked the idle switch on the throttle body. This was clicking fine but I noticed that the potentiometer was looking a bit worse for wear. Because it sits close to the down pipe from the turbo it got a bit roasted shall we say even with some heat shield rapped around it. I did not know at the time if it was either the idle switch or the potentiometer at fault so I managed to get hold on a replacement throttle body from VW Audi breakers in Melksham. Fitted it and jobs a good 'un. Just need to tweek the idle to make it perfect. I'm also going to build a better heat shield to protect it as well.

_________________
Present cars: 1989 90Q 20V. 2001 S8
Previous cars
1990 90E. Died a horrible death
1995 80 2.0 Sport. Hit a deer. Both car and deer written off. Kept me in venison sarnies for months tho!
1989 CQ 10V. Ebay mistake
1990 90Q 20V. Ebay bargain
AOC 1503 
View user's profile Send private message
Display posts from previous:       
Post new topic   Reply to topic

View next topic
View previous topic
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You can attach files in this forum
You can download files in this forum


Forums ©