Idle went haywire last night, possibly the o2? 84 4kq

[Johnny B]

Well I've made some headway! I found that my idle switch button was actually funked up making the 'click' a very hard press (grease & grime build up). After some contact claner & q-tips it clicks as it should, and now responds as it should. With the idle switch working I adjusted the static setting back to where it was marked when done with properly tuned with the voltmeter (I've tracked all static adjustments so once sorted I could return it to where it should be) which gave me a silky smooth idle.. that is until its heated up. Once ran on the highway for a bit it's back to gas fumes @ idle and a varying idle (drops kinda low then jumps back up, low, then back up, then it will kinda stabilize but still very rich) so now it's back to a borked o2 sensor but this time around Im very excited knowing once replaced I will have a smooth idle once again with the switch now repaired. 

2 birds with one stone, I found while having the intake boot off I could see my exhaust leak culprit (loose flange nuts) which got a good buttoning up. Still a bit of a leak but much much less (Im assuming some of the bottom nuts may be loose as well, I'll be checking in to that during the o2 replacement.)

Thanks for the kick in the motivation here guys, it's becomes tiresome chasing that next broken part sometimes..... 

Johnny

> Date: Fri, 3 Dec 2010 20:27:48 -0500
> From: audi at humanspeakers.com
> To: pre95 at live.com
> CC: quattro at audifans.com
> Subject: Re: Idle went haywire last night, possibly the o2?
> 
> 
> 
> On 12/3/2010 4:27 PM, Johnny B wrote:
> >
> > Hmm... well here's the thing, my idle switch has been bad for some
> > time now awaiting replacement (now bumped up in priority) but the
> > idle has remained pretty solid (using the static adjustment to
> > compensate).
> 
> People use that static adjustment to compensate for many things that 
> should be fixed, eventually it doesn't work any more, and they've also 
> moved the static mixture far from baseline in the process.
> 
> Replace that idle switch first.
> 
> > Now after months of this, the sporadic idle creeps up on
> > me. I'll be doing a thorough check of all vac lines again (ISV&  X +
> > all rubber lines have already been replaced, possibly something came
> > loose) and will also inspect the wiring to the ISV. Maybe it's time
> > for a good cleaning as well..
> >
> > Thanks for the help!
> >
> > Johnny Pre95
> >
> >> Date: Fri, 3 Dec 2010 13:52:00 -0500 From: audi at humanspeakers.com
> >> To: pre95 at live.com Subject: Re: Idle went haywire last night,
> >> possibly the o2? CC: quattro at audifans.com
> >>
> >> That could be a bad idle switch (or its wiring).  If the ECU
> >> doesn't know your foot is off the throttle it won't try to regulate
> >> the RPMS and they will usually cycle with the OXS.
> >>
> >> The switch is on the bottom of the throttle body, IIRC, and shares
> >> a connector and harness with the WOT sw. on top of the TB.
> >>
> >> On 12/3/2010 12:37 PM, Johnny B wrote:
> >>>
> >>> So getting off the highway in my 84 4000q, I realize my idle is
> >>> no longer stable, and is now varying between 800rpm and 1200 rpm
> >>> (Up then down then up then down then up then down etc etc).. I
> >>> also noticed a strong odor of fuel at idle that wasnt there
> >>> before.. Im assuming my o2 bit the dust but wasnt sure if it'd
> >>> give the idle adjustments on the JT like a dead o2 does on newer
> >>> cars. insight appreciated!
> >>> _______________________________________________ quattro mailing
> >>> list http://www.audifans.com/mailman/listinfo/quattro
> >>> http://www.audifans.com/kb/List_information
> >>>
> >>
> >> -- Huw Powell
> >>
> >> http://www.humanspeakers.com/audi
> >>
> >> http://www.humanthoughts.org/
> >> _______________________________________________ quattro mailing
> >> list http://www.audifans.com/mailman/listinfo/quattro
> >> http://www.audifans.com/kb/List_information
> >  _______________________________________________ quattro mailing
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> > http://www.audifans.com/kb/List_information
> >
> 
> -- 
> Huw Powell
> 
> http://www.humanspeakers.com/audi
> 
> http://www.humanthoughts.org/