O2 sensors at WOT?

[Mark Romans]

The engine actually stays in closed loop at WOT,  it just won't learn and
ignores the 02 sensor and goes to a richer "Commanded" air fuel ratio.  Per
PP Fenske,  it the engine has learned to add more fuel via block learn and
integrator it will add these same amounts at wot,  however if it is pulling
fuel out, it will go to 128.  If you have diacom it shows what the commanded
afr is.  My 87 Vette shows 11.91 to one commanded at the higher rpms with
the stock chip.  GM keeps it safe by keeping it rich.  If your engine flows
a lot more air than stock and has headers and a modified map you will
probably want to add more fuel otherwise before I put the headers on it ran
better with less fuel than stock.  After headers I had to go richer than
stock.
Mark
-----Original Message-----
From: Mark Wilcutts <markw at vehicle.me.berkeley.edu>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Tuesday, November 03, 1998 12:14 AM
Subject: Re: O2 sensors at WOT?


>On Mon, 2 Nov 1998, Bill the arcstarter wrote:
>
>>  I've heard that most ECU's go into an open-loop condition while under
>> WOT.  I've also heard this is because most O2 sensors read incorrectly
>> under WOT conditions.
>>
>> Why is that?  Does the increased gas flow cool the O2 sensor down too
>> much or what?
>
>Might be because WOT enrichment pegs the O2 sensor to the rich side.
>