Focus cold start over-reving

It's worth checking the air hoses around the air temperature sensor. Just an idea - a split hose on my Cavalier caused a similar problem.

How much and when? If its ~1100rpm at start up then say you move off the then clutch to stop at a junction and the revs shoot up to ~3000rpm but then eventually come back down again when you become stationary again, then this is normal, and a quirk of the car!

Tim..

This is NOT normal ...

I would have noticed it before in the 60 000miles I've covered in the car!

repeat of inquiry ....

but recently overevs from cold ... starts at 2000rpm then builds when clutch is dipped to change gear goes to 4000 would go more if left to it's own devices ... continues accelerating when in gear

as soon as it's warm it behaves normally

where do I start looking?

CheeRS

In your previous post you didnt mention how high the revs were going. 4000 immediately from cold start is not normal as you surmise. 3 items to check in order of likelyhood. TPS and wiring (0.6v with throttle closed, 0.7 max) Clutch switch on pedal, open circuit as soon as pedal pressed and finally sticking ISCV but I doubt it as its revving, not stalling.

Tim..

snip

no split hoses

snip

all this checks out OK

ALSO ... it's stopped doing it I've had 2 trouble free days ...

I suspect some strange electrical glitch probably a dirty wiper on a potentiometer !?!

Thanks for the input.

CheeRS

I've never found a TPS to have that sort of effect on idle speed.

Especially on fords, a tps value of over 0.7v with the throttle shut will cause the idle to stick high, and be slow, if at all, to settle back to natural idle. A lower value than about 0.55v will often cause stalling and the overrun cut off to stop working.

Tim..

mike, my father had a similar prob with 1.8 t reg focus over reving etc turned out it was the cylinder head temp sensor located just in front of the altenator costs £10 from ford and cured all probs

In a flurry of electrons Tim.. spake thus:

Yup, mine does it.