weird o2 sensor readings? (mc'd urq)

Michael S. Williams mike at borderlinemotorsports.com
Thu Jul 10 19:43:15 EDT 2003


At 2:18 PM -0400 7/10/03, Nate Stuart wrote:
>Todd, I think what you are describing is characteristic of the CIS
>injection system. The metering plate is far enough from the throttle
>that when there is a sudden change in throttle position it takes a
>bit for the pressure difference to equalize back to the CIS metering
>head. Have you checked to make sure your WOT switch is in good order
>all the way back to the ECU? Thats really the only throttle input
>the ECU has to know that you wanna go somewhere in a hurry.
>Everything else is based only on the current intake manifold
>pressure (ECU adjusts things according to this), and air flow over
>the CIS plate (CIS distributor adjusts things), sharp pressure
>changes at one end will take a moment to propogate through all the
>intake plumbing to the other, hence the quick lean dip you are
>seeing.
>
>Thats my theory anyway, feel free to flame me for anything I'm overlooking.
>
>If you physically feel the car stumble when you stab it quick then
>there may be something amiss, have you compared your O2 sensor
>behavior with anyone elses Turbo CIS'ed rig to see if yours is
>unique?

the only thing i'd say to this is that the actual flow of gas is
going to be proportional to the amount of air coming in through the
plate, not the throttle body...  there will be a drop in pressure (or
increase of vacuum) for a split second until the air fills the gap
there, but that would create a temporary rich-running condition, imo,
if anything...
--
MswmSwmsW

     <<<->>>=<<<->>>=<<<->>>=<<<->>>=<<<->>>=<<<->>>=<<<->>>
The solution is obvious.  We all have to become dumber. -Jon Rappoport

So crucify the ego, before it's far too late
To leave behind this place so negative and blind and cynical,
And you will come to find that we are all one mind
Capable of all that's imagined and all conceivable. - TooL, Reflection
      <<<->>>=<<<->>>=<<<->>>=<<<->>>=<<<->>>=<<<->>>=<<<->>>



More information about the quattro mailing list