Ford Idle Speed Controller

[richie]

I am running an M800 based on TPS/MAP with a 1993 Ford 5.0L windsor small block. It is more or less a daily driver so am trying to setup the ISC Ford part # E9AZ9F715AA for cold starts without much luck. It operates at 160 Hz square wave & zero signal is minimum duty cycle. I am told duty cycle can be anywhere from 20% to 80% but realistically between 40% to 60%.
Has anyone done any work on this type of setup. Seem to be too lean at start then cant get enough fuel in then it turns too rich.
Any ideas?

AaronM - file attached.

Richie

Richardiac.e35

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[RossB]

WHat type of inlet manifold and throttle do you have? Is your MAP sensor referenced to MAP or atmosphere? If it is not referenced to MAP you have no fuelling compensation to account for the valve position. Also the PID parameters you have are not going to give a very fast response, have you tested this?