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Discussion Starter · #1 · (Edited)
How does the ICV function?

The story:
My E36 1997 323i idles badly on a cold start, once warmed through (10 secs to a minute) its fine. :mad
Suggests ICV to me but I don't know much about its job (connecting "starting" with "idle" I suppose). I have had this and similar problems before and they have been "fixed" several times, only for it to return:
1. Cyclone valve replaced for MOT.
2. New spark plugs as old ones were missing bits of the ceramic nose cones.
3. Replaced both lambda sensors (reported heater failure on both).
When working well last summer I was getting 32-34 MPG, but at the moment its 29MPG (and I know its cold which may make a difference: -2 deg C this morning!).

The question:
I have cleaned the ICV twice, the second time last weekend. When the ICV is clean and off the car, I can move the valve and the plate/barrrel rotates freely inside and bounces off each end stop. It appears to sit such that it is about half open when off (can add photo of its position if it'll help).

While it was off the car, I plugged it back in to see what it did. The valve plate/barrel did not move but it vibrated and buzzed like an electric razor. :confused

How should the ICV work normally? Is this normal or am I likely to fork out £100 for a new ICV (anyone know of a cheaper one?)


Hopefully this edited post is clearer than my last :)

Thanks in advance for any help
 

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The resistance of the valve should be 20 - 25 ohms, I would say the best thing to do will be to get the car on a good scanner that has the ability to actuate components and have them test the ISCV, it should open and close, you will be able to watch this while they do it.
 

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Discussion Starter · #3 ·
Cheers, I have had a look through Carsoft 6.5 that I've got but can't see any live data parameters on this. Will check the resistance quickly though - is it the outer two pins?
 

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Will check for sure tomorrow but IIRC Pins 1-2 should be 20 ohms, 2-3 = 20 ohm, 1-3 = 40 ohms, They are all +/- 5 ohms.
 

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Right, for a 323i e36 1995 onwards

between terminals 1 and 2 there should be 20 -25 ohms.

2 and 3 should be 20 -25 ohms also.

With ICV plug disconnected and testing voltage between terminal 2(centre terminal) and earth there should be battery voltage.
 

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Discussion Starter · #7 ·
Ronnie,

Checked the terminals and got 11.9 ohms between one pair and 10.6 ohms between the other. Between 1 and 3 I get the sum of the above. I guess this isn't right when compared to your values above :D

When talking about a testing voltage, what voltage are you applying between terminal 2 and earth (the case of the ICV ??) and where do you measure the battery voltage?

Thanks for your help so far :)
 

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When talking about a testing voltage, what voltage are you applying between terminal 2 and earth (the case of the ICV ??) and where do you measure the battery voltage?

Thanks for your help so far :)
Checking for voltage with a multimeter :thumbsup, should be battery voltage, so if you check the battery and it reads 12.2 volts then should be the same between the terminal 2 and earth :thumbsup
 
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