weird o2 sensor readings? (mc'd urq)

[Nate Stuart]

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?

-Nate
'89 90tq
www.newtsplace.com/90tq

Todd Phenneger wrote:
> Michael,
>   I have a similar problem but I have power when lean, it just
> scares me to be leaning out.  My car will lean out for about 1/2
> second when I floor it then it will go back up and the power
> comes on.  If I push the accelerater smoothly over say 1-2
> seconds to the floor it will not lean out and has much more
> power than if I simply floor it.  I am suspect of my fuel pump
> and will be re-checkign my statick Fuel Pressure again but am
> not sure.  I have tried a couple differetn CIS units and all
> have the same effect.
>   ANyhow, I would call JC WHitney and order that Fuel PRessure
> Tester or get one locally. :-)
>   l8r
>      Todd