[200q20v] Rich Running

Gene Caldwell optic at halcyon.com
Thu Jul 12 13:39:53 EDT 2001

Derek Pulvino wrote:
> Hey all,
> Anybody have any suggestions as to what would cause rich running in the 200?
>   Haven't run fault codes yet, but I have noticed on startup the car runs
> rough, idle fluctuates, and once in a while will emit a gray cloud on
> startup (like this morning).  From the smell, I'm real sure this is fuel,
> not oil burning.  Also notice while driving hard often times I'll get a
> catalytic converter smell, this with the car warm.  From what I know about
> cats, doesnt this also show rich running?  Don't the cats function to remove
> unburned hydrocarbons before they can be released to the open air?
> Although gas mileage hasn't been noted to diminish lately, my guess is the
> car is running rich across the board, just don't know why.  Anybody think a
> bad tbv would contribute to this?  The car also stalled on letting off the
> throttle last night.

On the worst days I would get a small puff of gray-tan startup smoke,
followed by ragged idle for several minutes until the motor warmed up. 
Also, once in a great while a stall would occur during throttle close
under high boost.  I noticed progressive improvement while:

1) replacing fuel pressure regulator
2) ultrasonic cleaning of injectors and replacing seals
3) replacing the TBV and associated vacuum line

Replacing the TBV and vacuum line was the big surprise.  Fuel economy
jumped up, boost decreased slightly, starting improved, and overall
running is cleaner. 


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