OK, the IAC is now working and under MS control. <img src="/forums/images/graemlins/kewl.gif" alt="" /> After some bench testing and checking on the running engine, I've found what appears to be a work-around - the intuitive way to wire the coil (and how the MS manual suggests) doesn't work.... that puts the coils in same polarity. For the motor to be controlled, one coil needs an opposite polarity. The next issue I found was that it worked in reverse (extended with key switch ON), so I swapped the wires coil/coil and it retracted on key switch ON.

Viewing the IAC motor connector with the 2 blades on top (as shown in the FSM), the pins are numbered L-R, top row/bottom row....... 1/2/3 (top row) & 4,5,6 (bottom row).

Connect as follows:

IAC pin 1 to MS ECU pin 29 (S3)
IAC pin 2 not used (center tap)
IAC pin 3 to MS ECU pin 31 (S4)
IAC pin 4 to MS ECU pin 27 (S2)
IAC pin 5 not used (center tap)
IAC pin 6 to MS ECU pin 25 (S1)

Now, it wouldn't extend after engine starting, so I changed the 400 Hz Time Step Size from 2.5 milliseconds to 6.0 milliseconds. Apparently, the Mitsu stepper motor is slower reacting. Since longer time step size will generate more heat in the stepper motor, I may try to bring the value a little lower.

Anyway, I now have it idling at 950 rpms and not sure what to do next. It's surging at idle.... hunting around 14.7, trying to go lean, but the wideband brings it back in line.

My lowest bin for the tables is 30Kpa. I wonder if I should have a bin at 20Kpa.

Frank