Oxygen sensor and high speed stumble UPDATE

[Bruce Plecan]

-----Original Message-----
From: The Thibodeaus <vettenuts at efortress.com>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Saturday, October 31, 1998 2:20 PM
Subject: Re: Oxygen sensor and high speed stumble UPDATE


  I pulled the oxygen
>>sensor tonight and it had some black soot on it indicating a rich
>>condition.

That's not like reading a spark plug, if you look in the tail pipe it's
all sooty.

 Here is my question, by upping the fuel rail pressure to 48 psi
>>am I starving the engine at high RPM because the pump can't flow enough
>>fuel at that pressure?  Does this seem logical?  I increased the pressure
>>compensate for a ported plenum and also to overcome a pinging problem
>>(several prior posts made to this board and Vettenet on this nightmare)
but
>>it hasn't worked.  I am working with the chip programmer to resolve some
of
>>the pinging problems because I have found that they completely shut of the
>>EGR function.  So, should I lower my pressure?  Any suggested value?
>>Thanks for any suggestions.
>>
>>Bob T
>>
>Today I ran the car up in second gear with a fuel pressure gage taped to
>the winsheild.  The pressure never really dropped below 40 psi so it looks
>as though the fuel pump is OK.  The knock sensor pulled out about 4 degrees
>of advance maximum.

It pulled out 4d of timing

The oxygen sensor was reading about the mid 900 level
>millivolts at WOT.

Fine/OK ish

The maximum advance at WOT was 29 degrees.  One thing I
>did notice though was that the Auto X-Ray never indicated open loop at WOT
>even though my integrator and block learn were at exactly 128 which
>indicates that it was not using these parameters.  Any comments are
>welcome.

The ecm goes basically open loop at full throttle in your car.

 I don't have a correlation of oxygen sensor voltage to AF ratio,
>am I too rich?

Pull a spark plug, and see what ya got
Bruce
>
>Thanks
>
>Bob T
>