Hi all, I'm justing doing some work to TF I just bought, its was idling too fast yesterday but i got it right, but this morning I gave the throttle body a clean out, now its idling even faster than yesterday, was 1200 rpm yesterday, now its about 1800 rpm and that with the adjustment screw all the way in, any help would be much appreciated, cheers

What adjustment screw?

You mean the air screw on the throttle body? It's not meant to be used for idle adjustment.

The ECU controls idle through the ISC, or it is meant to. If the ISC is broken and wide open, you will get this problem.

The Haynes manual must be wrong then, thanks for your reply I will check the ISC.

ISC is fine, I know the car has a leaking heater core so maybe the leak has damaged the ECU

The air control valve sounds like your issue

The air control valve sounds like your issue

Ok cool, thanks Mal, I will check it out, is that the butterfly valve in the throttle body? cheers

No it is the valve under the TB which gives you a fast idle when cold, if this is stuck open it is a throw away item and needs to be replaced

No it is the valve under the TB which gives you a fast idle when cold, if this is stuck open it is a throw away item and needs to be replaced

Ok cool, thank Mal I will check it out

No it is the valve under the TB which gives you a fast idle when cold, if this is stuck open it is a throw away item and needs to be replaced

Is that near the ISC motor?

No, is the Air Control Valve, best you have a look in the manual mate, is on the TB and under it, has the coolant pipes going into it

has the coolant pipes going into it

Check that the water pipes actually get hot, there may be a blockage in one of the hoses or in the valve itself. I've seen a similar system bypassed because the metal was corroded, check that there are actually 2 hoses attached to the thing. (lol ??)

It has a wax pellet in it that needs to warm up so the valve can close the air flowing through it, to lower the idle as the coolant heats up.

New throttle body from a wreckers perhaps? (with ISC, valve of course.)

PS. How did you check the ISC?

Check that the water pipes actually get hot, there may be a blockage in one of the hoses or in the valve itself. I've seen a similar system bypassed because the metal was corroded, check that there are actually 2 hoses attached to the thing. (lol ??)

It has a wax pellet in it that needs to warm up so the valve can close the air flowing through it, to lower the idle as the coolant heats up.

New throttle body from a wreckers perhaps? (with ISC, valve of course.)

PS. How did you check the ISC?

Hi Max, thanks for your help, I have another car here the same which is running fine, I swapped the ISC over on both, the new car still idled too fast but the other car was fine with the new cars ISC in it.

Hi Max, thanks for your help, I have another car here the same which is running fine, I swapped the ISC over on both, the new car still idled too fast but the other car was fine with the new cars ISC in it.


Clever!

No, is the Air Control Valve, best you have a look in the manual mate, is on the TB and under it, has the coolant pipes going into it

Cool thanks Mal, I will have a look