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I don't know how VL400 knew, but I think he was onto something with my iac motor.

I used to be able to hear the loud whistle through the iac before with the banana manifold and standart throttle body but since putting on the come manifold i have never heard the iac working/whistling.

I was putting it down to the different setup and the way the iac sucks through this little screen at the rear of the new manifold.

anyway,

I undone the screen and stuck my finger over the suction hole (the hole the iac sucks through) and nothing. I played with the idle settings and comanded the iac open to 196 steps... then tried no steps... nothing changed, no suck. (i was just changing the desired idle rpms to get the iac to open or close and was revving in between to reset it.

No matter what i do it doesn't seem to move but the dash is saying it is...?

I have a feeling I may have buggered the motor when i screwed it to the manifold. I was thinking it was like a solenoid with the plunger but today i realise it is like a worm gear.

When i put the iac onto the come manifold i did notice that the plunger hit the backstop but the housing still had a couple of mm to go so thinking it was spring loaded... I just tightened it up till the housing was flush and tight and i think i may have stuffed the iac.

Maybe it had too much pressure on it and couldn't move and burned the motor out... don't know.

Is there any way to test it?

There is 4 little wire things that work the motor. I put my multimeter on the continuinity tester and couldn't get anything through the pins.

does anyone know if it is 12 volts? or maybe someone might know how i could test the 4 wires from the harness to make sure the motor is seeing the volts?? I did have to re make the whole engine harness as I had to move things around for the new manifold and I also moved the alternator to the opposide as well so i could have made a mistake... but i'd doubt it.

any help wood be great thanks.

The IAC valve has 2 coils within it.

ECM pin C4 = IAC coil "B" high and is transmitted via a LG/W wire to pin A of the IAC plug
ECM pin C3 = IAC coil "B" low and is transmitted via a LG/B wire to pin B of the IAC plug
ECM pin C5 = IAC coil "A" high and is transmitted via a LBLU wire to pin C of the IAC plug
ECM pin C6 = IAC coil "A" low and is transmitted via a LBLU/B wire to pin D of the IAC plug.

Resistance between (A and B) and (C and D) of the IAC plug should be between 40-80 ohms.

From memory you should be able to push the stepper motor plunger back into the IAC if it is extended out to far during installation.

there ment to reset everytime the ignition is turned on, they step in and out to reset, so perhaps pull it out, hold it together so the parts dont go flying then get someone to turn the key and see if it moves. As above you can push it back in then it'l reset the next key turn again.

Another test you can do is place two test lights between (A and B) and (C and D) of the IAC plug and with the engine running cycle the IAC steps back and forth.
Each light should cycle on and off but never stay completley off.

Ok, I have the iac in my hand and I tried the ohms tests, continuinity, I tried whacking it, I think she is dead.

There's only one thing left to do...

pull it apart and have a look inside it I'll get out the dremmel and whiz it apart in a minute and have a look.

I had a quick look on ebay, they're pricey little things hey, $140.

I recently purchased the same style of IAC for my holley throttle body for only $84 delivered from the US.

well, i'm in and I think i see the problems.

there is 4 little tiny nano microscopic wires coming out of the 2 coils and it looks like they are supposed to be soldered to those 4 pins inside the housing.

They are about the thickness of a hair on your head. I'm going to give it a shot and see if i can fix it, when i put the ohm meter on the wires I am seeing resistance and there is nothing obvious that i can see like no burned stuff.

wish me luck, if not looks like i need a new one.

cheers

well, what a job.

I couldn't find my small soldering iron so had to use the 80 watt one, grat big clunker with big tip.

anyway after much swearing, i've managed to solder the pubes back onto the pins and get the unit back together.
I now have continuinity between the 2 coils and 52 ohms in one pair and 53 in the other.

I just hope i have them on the right pins. I couldn't tell which went where because they were not sitting in the order, just sort of bird nested together.

I'll chuck it in and see if it works.

BINGO!!

ha ha, The pos actually works.

Seems to do everything right, the high speed part works and the stepper part also.

It runs on a worm gear and the pintel runs in a slot and worms in and out as the motor turns. I just set the iac to 200 steps at initial and key off etc and held the pintel in line with the groove at key on and then started it and kept it going into the slot as the stepper slowly pulled in to maximum in.

Then popped it in the hole where it goes and away I go.

Thanks.

Nice work Should be heaps better with the IAC working too.