ECU pulse width calculations...?

[John Dammeyer]

>
>Date: Mon, 13 Dec 1999 09:19:44 -0800
>From: "Andrew Brownsword" <asword at telus.net>
>Subject: Re: ECU pulse width calculations...?
>
>> Date: Sun, 12 Dec 1999 12:07:47 -0800
>> From: "John Dammeyer" <johnd at autoartisans.com>
>> Subject: Re: ECU pulse width calculations...?
>>
>> You haven't mentioned what the actual pulse widths were with the old
injectors
>> and then after you scaled them
[snip]
>My current theory is that my O2 sensors are carbon fouled and the ECU thinks
>it is running lean and thus richens up the mixture.  When I cut the values
>down far enough it goes beyond the ability of the ECU to compensate.  We're
>going to test the O2 sensors next, and see if we can diagnostic information
>out of the car's ECU.


In my ignition/injection controller I added the ability to turn off the O2
feedback so that I could tune the engine as best as possible in case an O2
sensor failed.  My O2 PI algorithm only adds a slight bit of correction anyway.

If it's a standard O2 sensor why not replace it with a pot that provides 0..1.0V
and set the output to 0.5V which is supposed to be 14:7:1.  Then,  because the
O2 is telling the ECU that the mixture is perfect it won't keep screwing around
with the mixture pulse width and you can see the real result of your tuning.

Cheers,

John