3.2 idle control valve go bad

[hcoles]

the valve has two modes

1- turning one way - one side is grounded and the other ground is open - current flows from the center (12v) to the one ground
2 - turning the other way - the other side is grounded and the previous ground is lifted - current flows from the center to the now other ground

so it sort of acts like two small independent motors... very German, everyone else in the world uses a solenoid - cheaper and more reliable - but no we got to use lots of parts, we like having lots of parts - the more parts the more money we make or something like that or Dieter used that 25 years ago and it worked.. so we keep doing it. That being said the 3.2 ICV does seem to be fairly reliable... minor compared to the valve guides going out.

[scarceller]

Originally Posted by rick-l

I was after how the current flows through the rotor to make the field point one way when one control is grounded and the other when the other wire is ground. Are there three wires on the rotor?

The control has 3 wires internally, the center pin is 12V and this one is wired to the bottom of the motor (the other end, not the one with the arc damage in the pic).

Then the outer 2 pins are the ones that get grounded and these get wired to the top (the one in the pic that has the arc damage) if you look at this top section you will see it is split into 2 halfs, one half is for each outer pin.

Then the motor is wound with 2 side by side windings, electrically it is like to seprate motor windings on one axel. So at one end (bottom) the 2 widings tie together to 12V and on the other end (top) each wire has it's own contact point that goes to the outer pins.

Hope this makes sence.

[rick-l]

Originally Posted by scarceller

The control has 3 wires internally, the center pin is 12V and this one is wired to the bottom of the motor (the other end, not the one with the arc damage in the pic).

That makes sense.

Does +12 make contact through a slip ring or is it just a wire?

[scarceller]

Originally Posted by rick-l

That makes sense.

Does +12 make contact through a slip ring or is it just a wire?

Rick,

I don't recall 100% but I do know the 12V center pin does not make contact via that 2 part split section that has the arcing, that section is for the 2 outer pins.

The +12V makes contact in one of 2 places: the top shaft it self, right above that arced section - or - at the other end of the motor. It's been 9months since I had mine apart and I did not take pictures.

[jcsjcs]

I just had my car serviced and replaced DME, Crankshaft Sensors, new shocks, tires, etc.

My mechanic also believes I should replace my ICV - as my idle is a bit rough when cold and a bit variable when warm. He suggests I buy a new one - as it is original (1984) - like pretty much everything else on the car...

Is cleaning a viable option / first step? What are the odds that I will damage the sensor - i.e. need a spare on hand OR be out of commission?

Also will I need to make any adjustments after I clean or replace the unit?

Thanks - jcsjcs

[ischmitz]

I'd clean it. There is no danger of damaging it. Use break cleaner or carburator cleaner. To check if it is working properly ypu can remove the ICV and disconnect both rubber hoses.

Then hook up the electrical connector, switch the ignition to ON (don't start the engine) and look into the tube of the ICV holding it in your hand. It should vibrate (80 Hz) and you should see the internal valve thingy jerking a little bit about every 3 to 5 seconds. If it does that it should be fine.

ingo

[jcsjcs]

FYI - I cleaned mine last night. Took it out and soaked the "valve" end in Brake Cleaner for a few hours. Seemed to loosen up a bit. When I took the car out today it seems slightly better - I am getting a couple of idle surges when I stop at a light vs. continual surging.

I think I will need to buy a new one to resolve the problem entirely, but will see if I can last the season as I have spent a bit too much this year already (new shocks, tires, DME Relay, Sensors, oil return lines, etc.)