Will computer lean mixture on WOT after some time?
Thread Starter
Teching In
Joined: Dec 2002
Posts: 20
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From: Midland, TX
Will computer lean mixture on WOT after some time? I have a Ford but was told by a Chevy friend that a common problem with LS1s was that the computer would lean mixture after a few seconds, say 10 of wide open throttle when the sensors indicate a rich mixture. Can anyone confirm?
Is there a similar computer strategy to richen the mixture at wide open throttle after a few seconds at a leaner mixture?
Here is a link to an Excel file showing what I recorded on the drag strip on Sunday on a 100 shot with one run on motor.
When asked to update links, reply "no"....
http://members.***.net/joelynch5/wall209.xls
Any input on what may be happening I will appreciate.
Joe Lynch
Is there a similar computer strategy to richen the mixture at wide open throttle after a few seconds at a leaner mixture?
Here is a link to an Excel file showing what I recorded on the drag strip on Sunday on a 100 shot with one run on motor.
When asked to update links, reply "no"....
http://members.***.net/joelynch5/wall209.xls
Any input on what may be happening I will appreciate.
Joe Lynch
Re: Will computer lean mixture on WOT after some time? Joe, I have been told that above 80% throttle, the computer swithes over to a pre-set fuel map. This seems to be correct, as my air-fuel gauge reads the same every time when under that much load. I'm not positive, but this is what I've been told.
Launching!
Joined: Nov 2001
Posts: 227
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From: Valencia, CA
Re: Will computer lean mixture on WOT after some time? The PCM will never lean the A/F mixture more than its original programming. On the other hand it does have the ability to add add'l fuel at WOT if during part throttle operation it has detected a lean condition and had to add fuel.
I've tuned several EEC-IV computers with various software. I remember a blower car on the dyno a while back that would add fuel under some unknown condition. At the time the software he had hadn't defined some key tables for adjustment. My guess was it was tied into an air temp/coolant temp parameter that added fuel.
<small>[ February 12, 2003, 01:23 AM: Message edited by: Mike Morgan ]</small>
I've tuned several EEC-IV computers with various software. I remember a blower car on the dyno a while back that would add fuel under some unknown condition. At the time the software he had hadn't defined some key tables for adjustment. My guess was it was tied into an air temp/coolant temp parameter that added fuel.
<small>[ February 12, 2003, 01:23 AM: Message edited by: Mike Morgan ]</small>
Thread Starter
Teching In
Joined: Dec 2002
Posts: 20
Likes: 0
From: Midland, TX
Re: Will computer lean mixture on WOT after some time? Mike--thanks. I think I have the problem narrowed down to a TwEECer problem writing a modified table back to the chip. I can only make the problem occur with the chip configuration set to one in which the timing tables have been modified.
I bought a used timing adjustor and will put that on, pull the TwEECer, and see if the problem reoccurs or not. My bet is that it won't.
I can't imagine a strategy within the stock Ford or GM computers which would modify the ratio at WOT after seeing something else change. But I thought I would ask since at least one fellow thought that the LS1 computer had done it.
Thanks again,
Joe
I bought a used timing adjustor and will put that on, pull the TwEECer, and see if the problem reoccurs or not. My bet is that it won't.
I can't imagine a strategy within the stock Ford or GM computers which would modify the ratio at WOT after seeing something else change. But I thought I would ask since at least one fellow thought that the LS1 computer had done it.
Thanks again,
Joe
