Revs Rising On Their Own?

[Hendry]

We've just gone and got a 2007 mk3 Renault Clio 1.2 16v (only done 27,000 miles from new) from my uncles after it lying for almost 3 years, less a couple of days in March 15 where it was ran to get an MOT. It was never decommissioned before being laid up, anyway new battery on it and it fired straight up and drove absolutely spot on despite having 5 year old oil in it, possibly the original coolant and everything else. Anyway got it home, turned it off and started it back up to see if the battery had charged a bit, only theres now a warning light on the dash which I've never seen on any other car and can only be described as looking like a heart rate monitor you get hooked up to if you're seriously ill in hospital. The car after starting and releasing the car continues to rev on its own like the accelerator is being gently pressed, only it isnt, it reached about 4000rpm on its own before I bricked it and switched it off before it hit the limiter and went bang! Tried it again and it rose to about 2500rpm, idled there for a while and then continued to rise, all the while the engine noise sounded awful, very "metallic"

 

According to the handbook the warning like that's on relates to either water in diesel filter, fault in auto gearbox or water in injection computer, must be that as its neither diesel or auto. I was thinking it could be a fucked idle control valve but then thought that'd surely juwet make the car juddery, idle poorly and then cut out, not keep the revs continuing to rise on their own? Also weird how it started fine, idled fine, drove fine and then idled fine until it was switched off then suddenly developed a fault.

 

Any ideas apart from it being a French piece of shite?

[Bren]

Its a Renault- be thankful it revs at all.

[cobblers]

Sounds like a stuck throttle body. Clios have a "ELECTRONIC INCIDENT" warning light which might be what you're seeing

[hairymel]

inlet air leak is always my first port of call for all random idle issues

[FakeConcern]

Temperature sensor failing can also give high revs (thinks engine is cold & operates automatic enrichment).

[Barry Cade]

inlet air leak is always my first port of call for all random idle issues

This- check the servo pipe...

[cobblers]

I should add that nowadays reading fault codes off cars is dead easy and cheap so you'd be a maniac if you chucked any parts at it without reading them first.

 

Cheapest option is a eBay bluetooth OBD reader that connects to your smartphone and works with an app. £4

Next step up is a £10 reader with an LCD on it, saves having to pair it with your phone and it's a bit more foolproof.

[PhillipM]

Check for inlet leaks, common on these around the rear of the throttle body.