Miatapower List Archive

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Mail From: "Tony Cooper" <(email redacted)>


OK all you FM ECU Power folks and/or Corky, Bill or Ray?

I was talking with a friend about our FM ECUs and he got me to thinking. (I know - very dangerous...)

A simple question but I suspect not a simple answer.

Why is it that we (or I) with FM ECUs have such a tough time with A/F Idle settings in their many configurations... i.e under voltage load, AC load cycles, etc and
the stock ECU handles these fine? I mean, the stock ECU handles idle wonderfully in all the same conditions without ever changing the code base. I'm forever
tinkering with mine and idle seems to change dramatically based on ambient temps, engine temps, voltage loading, ac loading, etc

What is it that I am missing? Is it this hard to get a stock idle set? It should be the same for all our cars right? Not like we are under boost or anything...

Please understand I'm not throwing rocks at Bill, Corky, or Ray... I think that they have done a good job at giving us options. The FM ECU really shines when
learning under all conditions with the exception of idle. The stock ECU never learns and idles great... What am I missing here? Anyone care to enlighten me.

Tony

PS: I realize the FM ECU really doesn't "learn" at idle, I'm just wondering why it proves to be so difficult to get it right. I would have thought that this would be the
easiest of the conditions to get correct right out of the box, hardwired so to speak, and that users of the FM ECU wouldn't even have to worry about idle at all.

Tony Cooper
93 LE #1388 of 1500
Raleigh, NC

93 LE Web Page: geocities.com/MotorCity/Speedway/8517/
My 93 LE Web Page: geocities.com/MotorCity/Speedway/8517/tony.html
AOL IM ID: TonyC00per

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Mail From: Ray Ayala <(email redacted)>


Very small changes in fuel pressure, fuel chemistry, voltage and injector
temperature are very exaggerated by using larger injectors because the
narrow pulse width at idle is close to the threshold of not opening at all.

At 10:30 AM 07/05/2000 -0400, Tony Cooper wrote:
>Why is it that we (or I) with FM ECUs have such a tough time with A/F Idle
>settings in their many configurations... i.e under voltage load, AC load
>cycles, etc and
>the stock ECU handles these fine?