[V8] Failed Emissions Miserably 1990 V8 Quattro Auto

Buchholz, Steven Steven.Buchholz at kla-tencor.com
Mon Nov 28 21:27:29 EST 2005

... have you checked the spark plugs to see if one or more are fouled?
If you find something like this, don't forget to check the spark plug
wires and distributor rotors/caps ... big HC numbers sound like a
misfire to me.  If the plugs and everything else pan out ... think about
doing a compression check ... you might also have a sticking injector
... might want to run some good injector cleaner too.  

When the smog tech did the test did they have a difficult time keeping
the engine RPMs stable?  I suspect this isn't a problem for you as you
are failing at idle too, but I had an issue once at high RPMs because
the tech was running the engine faster and slower trying to keep it
constant during the high RPM test ... 

As someone else pointed out ... there's a good chance that the ECU is
telling you that it is having problems controlling the mixture ... 

Steve B
San Jose, CA (USA)

> ------------------------------
> Subject:  Failed Emissions Miserably 1990 V8 Quattro Auto
> So, if I were as rich as my car is running right now I wouldn't be
> having this problem...I failed all aspects of the emissions test, all
> them.  Results are:
> HC ppm
> Limit   Reading
> 220      687 (2500+-300)
> 220      1208 (Idle 775+-425)
> CO%
> Limit   Reading
> 1.20     9.95
> 1.20     10.62
> What's really bugging me is that I replaced the 02 sensor over a year
> ago (passed then with no problems).  I also replaced the Fuel Pressure
> Regulator about 4-5 months ago.  What else could be affecting this?
> Right now I am assuming that I have a prematurely failing 02 sensor.
> What else should I look at?  

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