CIS-E3 problems - temperature sensor?

[john at westcoastgarage.net]

L DC wrote:
> Not to highjack Eyvind's thread but this goes along the lines.
>
> John, as in Eyvind's case, and as per the suggestion of a QSW Syncronized lister (http://autos.groups.yahoo.com/group/syncronized/), I have also done that quick test of unplugging and plugging O2 sensor on my VW QSW (JT code) to determine its effectiveness.
>
> No difference what-so-ever.
>
> Could you elaborate on that if you would please?
>
> From what I'm told, if my QSW has bad O2 sensor, the ECU would take over and make an estimated guess as to the ideal mixture of air/fuel?
>
> BTW, my car seems to run just fine, idles, runs and accelerates just fine. But could the car be running with no O2 input?
>
> -Regards,
>
> -Louis
>
>
>   
>> To: john at westcoastgarage.net
>> Cc: quattro at audifans.com
>> Date: Saturday, September 26, 2009, 12:59 PM
>> 2009/9/26 john at westcoastgarage.net
>> <john at westcoastgarage.net>
>>
>> Before throwing money at an O2 sensor, unplug it and see how it runs.  If
>> it runs OK, then the O2 sensor could very well be the problem.  If not, 
>> look elsewhere first.
>>     
>
> John
>
>
> --- On Sat, 9/26/09, Eyvind E. Spangen <espangen at gmail.com> wrote:
>
>   
>> From: Eyvind E. Spangen <espangen at gmail.com>
>> Subject: Re: CIS-E3 problems - temperature sensor?
>>
>> I've tried that, and it makes actually no difference at all if it's 
>> plugged in or unplugged. The problem has to be somewhere else.. I'm
>> starting to think along the lines of maybe a bad ECU..
>>
>> -- 
>> MVH/MfG
>> Eyvind E. Spangen
>>     
>
> I have experienced O2 sensor failures over the years that caused full rich conditions, sever stumbles, and no-start conditions.  If the O2 sensor shorts to ground, the ECU tries to richen it up, which makes the car virtually undrivable,  I have a 944 here in the shop right now that ran fine until it got warm, then barely ran at all.  If it stalled, you couldn't restart it until the CTS returned to cold, and even then it was iffy.  Unplugging it can help identify such a problem.  
>   

John
>       
>