Idle problem - ISCV at fault?

[mk1 clio]

nooo not another idle thread I hear you say :P
but i have read through about 30 idle related topics, and cant get myself an answer, so here goes.

The car has a rough idle on startup and erratic idle at times (when coming to a stop, putting clutch in, etc)

My suspicion's are with the ISCV.

Firstly should the air screw on the throttle body before the butterfly opening be fully closed? Because I can not get the car to run without it open, about one full turn, any less and it will stall instantly when i start the engine.

I thought this was the job of the ISCV, therefore making me think its closed all the time,

Ive tried cleaning the ISCV and its moving freely. so the only reason it would be closed all the time would be that its fubared.

So far Ive cleaned ISCV and TB
Checked all earths and added 6-7 new earths
Earthed speedo cable

Cheers in advance,

Darren

[MAXIBOY]

difficult to tell. does not sound speedo related so the valve sounds your most likely culprit. see if your can find a secondhand one though as there around a 100 quid new.

[Purple]

What is the state of your car? Anything changed lately? Anything need cleaning out (dirty plugs, filter etc)? Any oily bits on the engine? I would suspect ignition and fuel-feed components that's not been changed for a long while.

[mk1 clio]

cars had:

oil and filter change
fuel filter change
coolant flush
injector cleaner treatment
new plugs
leads
dizzy cap
Extra earths added
ECU is dry, no damp or corrosion inside it
there is a tiny oil leak underneath some were, but it never drips as much to leave any on the ground, and dosn't really use any oil (has used about 1/2 litre in the past 2000 miles

was wondering what you guys thought before i tried the expensive things, like the lambda, ISCV, or CTS.

I remember reading some were that the air screw on the TB should be screwed in fully, when i do that the engine stalls instantly, making me think the ISCV is always closed, would that be the case?

[Purple]

injector cleaner treatment

Is this one of those pour in the tank jobbie? If it is, then get a can of carb spray and clean out the TB properly. That's cheap and easy. With any luck, it might resolve the air-screw thing you mentioned (though I am not quite sure what you mean).

Also check the fuel-pump connector under the rear seat is having a clean solid contacts.

[mk1 clio]

yep put some of that stuff in the petrol,

Ive also taken the ISCV out and cleaned itwht carb cleaner, and also cleaned out the TB with carb cleaner.

Can the injectors be taken out and cleaned or do they need to be cleaned by a specialist?

Ill give the connections on the fuel pump a clean,
Cheers

Heres the air screw:



The car will not idle at all with it screwed in fully and just cuts out instantly if I do

[VIPERONE]

LAMBDA

[mk1 clio]

LAMBDA

Cheers, ill give that a go first then

Is there a way to check if an ISCV is opening as it should? And can anyone tell me if the air screw should be screwed in fully? or adjusted to let the car idle?

many thanks,

Darren

[cliokongen]

LAMBDA

Cheers, ill give that a go first then

Is there a way to check if an ISCV is opening as it should? And can anyone tell me if the air screw should be screwed in fully? or adjusted to let the car idle?

many thanks,

Darren

The air screw only affects base line idle and shouldent be tampered with.

Take off ISCV - clean it well, let it dry and lubricate with WD40 or similar.
The connector has 3 pins. Midlle is earth. The other two makes it open or close. Putting 12v over the earth and either of the two other will make the valve open and close fully if the valve is working.

I had one that was sticking a little bit when closing causing irratic idle.

Michael

[cliokongen]

LAMBDA

Cheers, ill give that a go first then

Is there a way to check if an ISCV is opening as it should? And can anyone tell me if the air screw should be screwed in fully? or adjusted to let the car idle?

many thanks,

Darren

Forgot - air screw is not fully in. I think its about half to a full turn out.
It wont fall out as it has an o-ring attached

Michael