timsrs

Hi
I have started my car for quite along time today and immediately notice the idle was hunting badly.
It would rise to 2000rpm and the drop to 300rpm.
When it was warming up it did improve and now when warm idles spot on at 900rpm.
I did exactly the same thing a few hours later and the car is still hunting.
i did unplug the cold start valve and it seems the base idle is set at the 900rpm.

Help needed please, not sure what to do next.
many thanks

William MK2 Cosworth

Maybe the idle control valve is sticking

Try taking it out and giving it a clean

SapphyMike

Id say that it was sticking to be honest. I have cleaned mine before on my old car and it made a difference for a while. Eventually I just disconnected it. Not ideal but stopped it hunting.

tonyRS

Mine does exactly this, but iv cleaned the iscv and then changed it for another but still the same! So il be interested in the outcome.

MrC

Air leak??

Rob Virgo

iTrader: (6)

Iscv out, dip in egg cup of petrol over nite and then while still in petrol carefully give the contact 12v and you will power the plunger introducing fuel into the hard to get internal surfaces,varnish from the fuel gums the valves operation and this procedure dissolves it.....

opposite lock

iTrader: (3)

Seems like a good way of cleaning one ^.

timsrs

Thanks for the help, can you buy new ones anymore.

Fezman1

iTrader: (1)

As said check iscv.
If buying new beware of cheapy copys.
Might also be worth a check at the water temp semsor(blue)
-although this is usualy rough running idle when cold & abit of black smoke (over fuelling)
You say its been sitting awhile, ive seen dampness in the plug holes cause similar idle issues, mite be worth popping the leads and checking this too.

martysmartie

iTrader: (1)

It's either the valve clogged up and so cannot operate smoothly, or it's knackered, or the valve is being told to operate in this way.

First thing is as said to remove and clean if it's 'gummed' up with carbon etc up.

They are very hard to get hold of and as said, having got one of the aftermarket ones I can say they don't work very well, the spring ratings are different and so mine run very fast with it, I messed around and fitted the springs from my old one to it and it has improved but it's still by no means perfect.

They are two different part numbers floating around, VAE 01 and VAE 06.

Martin

rapidcossie

adjust the idle screw under the opening of the inlet