E30 - ICV Wiring Order

[E30Bastard]

Hey Guys,

Hoping someone can help me hit the easy button here - look at the ETM but it only lists two wires vs 3.

Standing on the driver's side and from top to bottom is it white/yellow (confirmed, this is the only cable that stayed attached), red/white, white/green? The oem connector disassembled itself, just trying to sort this out. I'll probably have the answer to this before anyone replies but man I'd love someone's input right now.

[PEZ2]

This is from 1988 ETM. Not the best image but the section reference is visable.

[82eye]

if you don't have it download your etm from here : Index of /Manuals/BMW (wedophones.com)

get it now before it is gone forever. the answer is in there and much easier to read.

[E30Bastard]

Thanks, Guys! I'll get it soldered it up this AM. If anyone reads this in the future numbers 1 2 3 are stamped on the bottom part of the ICV connector. Very small numbers but you can see them with a flashlight without taking it out of the car.

[E30Bastard]

Ok, there is a mystery in the machine shop:

The failed female connector itself also has numbers 1 2 3 stamped on it and these numbers line up to the 1 2 3 stamped on the ICV male connector. White/Yellow is the only wire still attached to the female and it is terminated on #3 of the connector, which also connects to #3 on the ICV. The 1988 ETM shows W/Y terminated to #1 but the white/yellow wire looks stock from the factory...

I'm going to solder according to etm but it just doesn't seem right.

See pic:

[E30Bastard]

[2mAn]

I’d check the pinout on the Motronic ECU as it shows white/green going to Pin 22, and white/yellow going to Pin4. Weird though...

[E30Bastard]

The more I think about it, the more I think it doesn't matter which wire is soldered to 1 & 3. Alternating signal, even reversed, should do the same job. Kinda funny that this is an error from the factory.

I do remember there being a calibration process on the MS2 for ICV full open and full closed. Will need to revisit that after soldering.

I'm firing up the solder iron now and then I'll follow your advice afterwards, 2mAn.

[E30Bastard]

ICV settings were off, of course, due to open and close duty % being reversed, but the connector is soldered in the way the ETM says it should be now (even though it was wired in reverse from the factory and I don't know if the stock ECU would work with me flipping the wires like that, there must be some explanation from the 80s.). I spent some time calibrating last night but it got too late for revving, etc. Will tackle again after work and update.

[E30Bastard]

Well, she's a-runnin'. Flipped it from inverted to normal on the gui and messed around with the open/close % values. I think this ICV might be going bad, as there isn't much flex on rpm adjustment (yes, I serviced 24 hours ago) - either that or the tune is decent enough to hold it. If I remember the first time I calibrated I was able to get it from dying to 3kish. I'll mess around with it more tomorrow. I have 3 other ICV in a box hidden behind a massive cache of my wife's holiday decorations in the attic. Fun. Might just ebay another to avoid the insanity of finding those three to test against.

Forgot to unplug the icv while it was running and rev to see what happens. Looks like dyno can be on 2/7. Will resurrect my build thread with 1 million updates and a dyno sheet after that. Then turbo.

Anyhow, unless something crazy happens related to me flipping those two wires for all intents and purposes this thread is closed. Thanks, Everyone!

[e30davie]

not quite sure what your playing with here, but 3 wire ICVs work by the piston sits at 50% without any power applied and there's two solenoids one for open, one for close.

So there's is 3 wires on the plug, open, common +12v, close. So to operate one of these correctly on an ms2 you need to use 2 outputs.

not sure how you have wired it to the MS2, on my ms2 I just used a 2 wire from another car, which just requires 1 output.

if you have indeed wired it in using 2 outputs have you told ms2 to use a 3 wire icv? as you'll need to set which output is close and which is open.

[E30Bastard]

Hey e30davie,

I have it set to 3 wire. The wires came loose from a factory fitting and I am not sure why, but during the process of wanting to solder in a new ICV connector I discovered it was wired in reverse from the factory. My previous tune was set to the previous wire locations:

W/L to 3 instead of 1 and W/G to 1 instead of 3.

I corrected that and then needed to go from inverted, which was how I had it set to, to normal. My open and closed % duties are the concern now. I'm not getting nearly as big of a delta between the two values as I did before. I'm trying to find my logs.