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

[Johnny B]

Hey Tony (and all)

Thanks for the tip below! This morning after fueling up I pulled the spade connector and ran her up to temp on the highway. Rock solid idle when hot or cold now... I can definitely see why folks leave the o2 disconnected on the 4kQ considering how smooth everything is (my new one is in the mail so no worries there, I really want to dial in the tuning on this bad boy!). The idle & WOT switch are now responding as they should (confirmed with voltmeter) so the last piece of the puzzle is obtaining the necessary bits from the junkyard so's I's can get the static adjustment locked in. I dont know how much I trust the static tuning set by the previous owner as he mentioned tuning it "for smog"... if tuned properly you shouldnt have to compensate for smog. 

Johnny

> Date: Sun, 5 Dec 2010 23:07:24 -0600
> Subject: Re: Idle went haywire last night, possibly the o2? 84 4kq
> From: auditony at gmail.com
> To: pre95 at live.com
> CC: quattro at audifans.com
> 
> Jonny,
> 
> Glad to hear you are making progress. So, the Idle and full throttle
> switches are opperating properly now?
> 
> One quick way to test the O2 is to unplug it and see how the car runs.
> You only have to unplug the single black wire, that's the one with the
> signal to the ECU. The car will go to a base default setting, and
> should run better. If that's the case, you have found for sure the O2
> is bad.
> 
> The other way to check it is with a volt meter. Should fluctuate
> around .2 to .8 or so volts. Yours is probably stuck closer to 0
> volts, telling the car it's lean and causing it to dump extra fuel in
> to compensate.
> 
> Tony
> 
> On Sun, Dec 5, 2010 at 10:28 PM, Johnny B <pre95 at live.com> wrote:
> >
> > 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