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

[Huw Powell]

On 12/6/2010 12:11 AM, Vincent Gelinas wrote:
> In the same vain of testing the o2 sensor on my 89 90q, I have the plug to
> the harness and I have a green wire next to it. Which is the one I should
> unplug to return the edu to a baseline?

As covered previously by another lister, there are two cables to the 
OXS, both of which are connected at a cylinder head-mounted bracket near 
the throttle cable.  The single pin one is the signal, the two pin one 
is the heater.  Disconnect the single pin one.

Then find a friend with a trailer and get that pig down here!

> Thanks
>
> Vincent.
>
> On Dec 6, 2010 12:07 AM, "Tony Hoffman"<auditony at gmail.com>  wrote:
>> 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
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-- 
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/