when i start my cosworth it idles constantly at 2000rpm for a short time then its goes down in the revs an then picks up to around 2000rpm angain an back down again an constantly does this while idleing but when driving the car the is no problems. anyone have any ideas what the problem is? i dont want to drive the car until it is right again bear in mind this is a 380+ bhp cosworth so power might have something to do with it but i really dont know

regards shea

 

Idle speed control valve thats what it sound like to me its attached to the throttle half grey half chrome pull the plug off (at the top of the iscv as i mentioned dont worry it will not damage the car and see if it makes any diffrenceif so problem solved if not come back on and someone will help you they are common for fooking upmy mates escort cossie with a genuine 22k on it does it aswell so my moneys on that oh and welcome to PF get some pics of your car up

 

that was the first thing that popped into my head an tyred it an didnt make a single difference

 

Theres an air leak somewhere, most likely a faulty gasket most likely will be the plenum gasket.

Martin

 

yeh thats what 1 of my m8s said who works at cosworths now and again, he mentioned something about 1 of the vacum pipes could have a pin hole?

 

On the plenum you will see then there thin hoses.

Martin

 

thanks m8 we'l get a look at her on monday see if i can get it sorted




theres a few pics to show u's wat she looks like

 

does your power seem as if it is down a kind of a hesatation type feeling? I see you have a dump valve on there check it out aswell.

 

no power is still great when u put your foot down the turbo is laggy which you expect cause its a big turbo version but no hesatation at all its jus the idling thats the problem

 

mmm! does not sound like an air leak with regard to the iscv did you change it or just clean it. If you did clean it did you take it apart and put it back together properly with the little nut on the spring not screwed up too tight. Another thing could be overfueling.Good luck lad.

 

My bet is also the iscv, an airleak somewhere in the plenum would be a constant rise in rpm.

 

I thought it was constantly running fast, in that case no it wont be an air leak.

Know it sounds daft did you defently unplug the valve with engine running as when you do this it will drop to base idle, as only way engine speed can be increased except throttle is by the ISCV.

Overfueling wont cause the problem as the only thing to raise engine speed is air.

By the way car looks nice

Martin

 

Spray easy start around the gaskets to ensure sealed correctly, then check the CO, a lean mixture will cause this, maybe the CTS has gone duff, which is pretty std.
The FACT that the revs are raising above base idle(if set correctly) shows it to be WORKING, it's ONLY function is to raise the revs, which it's doing.
tabetha

 

car sorted lads plenum gasket had bust which caused 3 little srews to come loose on the manifold causing the air to escape so all is sorted nw thanks for every1s help