Hi guys.

I have read a few of the articles about the well known ISC which seams to fail quite often.
I have tried to buy a new unit and apparently Ford don't sell them any more. I have tried to get as much info about this little irritating piece of equipment. Now my problem is can I disconnect it and drive the car without the ISC ? I have seen this before on another Falcon and it ran sweet no problems. Hopefully one of you guys can give me some more info about this thing. What if I open the unit up and clean it is there anything that'll jump out and be gone for good or is it pretty straight forward inside the cover.

Thanks in advance.

Cheers

Yep, you can run it without the ISC. You will need to adjust the idle upwards a little (the screw on the throttle body) - you want it just high enough that it won't stall when cold. It will probably idle high once it warms up, but it's livable. If you try to achieve a near normal warm idle, it will die when cold - unless you're happy to hold the throttle open a bit with the accelerator pedal for a few minutes after every cold start.

I don't think there are any serviceable parts in the ISC. In fact, I'm not sure how you would open it. You can clean the valve part of it without disassembly. Just fill it with an appropriate cleaner, let it soak, then get a small bottle brush down the ports. I have read somewhere else on this forum that the valve itself is quite delicate and doesn't like strong solvents - isopropyl alcohol was recommended.

There is a felt filter inside the black cap on the side of the ISC. You can take it apart and clean it with methylated spirits, brakleen, throttle body cleaner, etc.

If you are replacing ISCs frequently, the problem may be in the ECU - worth checking.

Thanks for that mate, I bought some Throttle body come carb cleaner, so will try that on the weekend. I don't have a foam filter on my ISC, yes there is a black cap which when pulled off has a brass tube which goes into the unit.

Thanks again.

The black cap is a 2-piece unit, with a felt filter between the two. Not sure how important it is, but mine was filthy black when I cleaned it (soaked the felt in carb cleaner for a couple minutes then squeezed it dry).

Idle speed controller controls idle speed by allowing air to flow into engine by bypassing the throttle plate.Thus the little felt filter in the black cap is important as if it is blocked no air will get through.New idle speed control units are still available from ebay(both genuine Ford and aftermarket) for @$110,or any efi specialist should be able to source one for you.Note that replacing idle speed controller may not fix your problem,especially if you have a blown idle speed circuit in your ecu(usually indicated by car stalling and revving up erratically),also a faulty map sensor may also cause similar idle issues.A quick check to see if idle speed controller works is to turn on air conditioning,if idle speed increases slightly,then idle speed controller is working.What exactly is wrong with your idle that you want to replace the idle speed controller?
Cleaning the idle speed controller is pretty easy,just disconnect electrical connector and 2 mounting bolts to remove unit,then clean out internals with carby cleaner as stated above(do not wet the electrical part of unit and make sure it is completely dry before refitting.Also clean out the 2 small bypass holes on top of throttle body while unit is off.

Hi Thanks for the write up.

Unfortunately my ISC doesn't have any filter in the cap on the side.
What I found is if I accelerated or blipped the throttle the revs would hang and after a few seconds slowly drop down again.
Another thing is she does not start after first turn it takes about 4 or five turns of the motor before she fires up. I would assume it should fire after 1st swing of the motor.
If you have any ideas on that, I would appreciate it. I have disconnected the ISC as I couldn't drive the car anymore was getting worse and worse every day. Now she runs like a dream but had to adjust idle, would or could this cause any issues with the ecu looking for a pulse from the ISC ?
I will have a look on ebay as well.

Thanks again mate.

Cheers

You have to dis-assemble the inside of the black cap to get to the little round felt filters.If indeed yours does not have a filter,I would find one that does as running car without that filter will allow dirt/dust to enter engine(just like running engine without an air filter).
Rev hang usually caused by vacuum leaks or sticking throttle cable/throttle plate.Vacuum leaks will also cause car to take longer to start due to air fuel mixture being too lean.Make sure butterfly valve in throttle body is clean/free of dirt(clean out with carby cleaner,and make sure it closes properly)lubricate the throttle shaft/throttle cable while you are there,check inlet manifold gasket for leaks,and check that idle speed controller gasket is not shagged/leaking..Also check operation of PCV valve(pull it out and shake it,if you can hear the little ball inside rattling then pcv valve is ok)and check that the pcv valve hose is tight and does not leak vacuum.
Car will run fine with idle speed controller disconnected as long as idle speed is adjusted up slightly to overcome cold start friction,thus allowing car to idle when cold.You will however lose lean cruise mode,so fuel economy may not be as good when cruising on long trips.