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Posted: Fri Feb 10, 2006 7:37 am
by midnightblue
Glad you got the IAC sorted out.

I'm not up to speed on the spark stuff, I'm currently running fuel only. I have EDIS to play with as soon as the weather improves, but I'm more likely the end up asking the questions on that!

I'm sure the others will help you sort out the ignition side.

Matt.

Posted: Sat Feb 11, 2006 2:00 am
by mattrampone
Thanks matt,
sounds like a cool project you have got comming up, I'm curios to hear how it works out for you! 8)

Posted: Mon Mar 06, 2006 4:32 am
by blown87
I am expiriencing the extact conditions with my IAC that mattrampone described earlier. I have the factory wiring diagram and have it wired as shown in Metatune diagram.
So just to clairify, did you determine that another wiring combination (other than what was shown in the Megatune diagram) fixed the problem?
This is on a 1987 Tuned Port Injected V8 Chevy with the square IAC connector.

IAC probs.

Posted: Tue Mar 14, 2006 9:51 pm
by mattrampone
Sorry to have been away for a bit, But to answer your question yes, I did wire it differently. First make sure that your step size (in milliseconds) is set large enough that the motor will be able to keep up. Mine is @ 1ms.
set your start value to like 300 to start with. Keep in mind that the start value will back the pintle valve out when key is cycled on. (backwards). All other values entered (like cranking steps) indicate the number of steps the pintle will move in from the start value referance point. The 300 steps should be enough to cover the whole distance the valve can move, however you will want to set it up when you get it wired proper. It has been a while since I did it so I can't remember exactly how I wired it, But I do remember this. My mega squirt dia. indicates 1a 1b 2a and 2b. If you are like me and trying to match it up to a GM wiring dia. you will find A hi A lo B hi and B lo. The GM a's and b's are not the MS a's and b's, but rather the 1's and 2's.
I figured this out via plan "B".
I was told that there is like 12 combinations of ways to wire it, so I started eliminating them.
A helpful tool is a multi meter. your IAC has 2 coils, you can find them with the ohms setting, look for continuety across the pins to find a coil. One coil gets a's the other gets b's. Plug it in turn on power and observe pintle movment. It should retract 300 steps (or try to after it bottoms out) and then extend out 100 steps or whatever your cranking value is set at. It should work consistently, If it goes backwards swap the polarity (1a to 2a, 2a to 1a and the same for the b's, dont make mistake of swapping coils or you will be the same as before)
If that still doesn't get you going try jumpering the two fat 1k resistors under the daughter card to give the iac full power. These resisters are there as saftys incase you short the wires so be bloody carful after you do that, or you might need a new iac driver.
That should get you going, let me know how you make out :)