Help diagnose my excessively high idle speed!!

[LeeJSA]

Bit of a strange one this...

Drove to Coventry last night, car drove mint no problems at all. Parked it up round the back of my mates house left it there until around 10am this morning.

Started it up & for some bizarre reason it was idling at 3000rpm!! Drove down the road to see if it would clear but it seemed to make it worse as it started to idle at around 6000rpm instead. So I parked it back up at my mates & left it there all day.

Came back to it tonight as I was about to ring the RAC so they could take me home, started it just out of curiosity & it was absolutely perfect!!!!!

Then drove over 100 miles home absolutely perfectly up until I was on my last stretch of dual carriageway, I gave it a bit of caning, around 6000rpm in 3rd gear & the engine management light came on & I was left with limp mode for the remaining mile of my journey. Turned the engine off & back on again, engine management light went off but I had 3000rpm at idle again!!!!

Now I'm thinking its got something to do with the fly-by-wire system - throttle body or pedal.

Anyone else got any ideas what it could be?

 

[jonny mac]

i'd get it plugged into a diagnostic machine, idle control valve could be one of them that's gone

it could be alot of things, have you checked your engine oil lately aswell i know that sounds silly but just to be safe.

i'll ask my mate tomoro as he's a mechanic at renault

 

[drhowser]

could be the potentiometer

 

[FeelX]

When the electronic throttle body is disconnected the car will idle on 3000rpm (safe mode), so there might be a electronic problem with the throttle body or connector or "maybe" the gas pedal position sensor (potentionmeter).

However running idle at 6000rpm seems strange to me.

 

[Neal 182]

could be temp sender mine was reving up at around 2k and that was temp sender

 

[LeeJSA]

Hmmmm - think I'm going to swap everything over onto cable throttle to be on the safe side, besides you get better throttle response I heard!! It needs doing before I fit my throttle bodies anyway so this gives me the excuse to do it...

Just to confirm what I need to do this...

Pedal
Throttle Cable
Throttle Body
ECU (preferably unlocked)
Loom? or is this the same?

Thanks for your help guys.

 

[gtruk]

Loom afaik should remain the same. Might as well buy an omex ecu as you will be needing that for your tb setup anyway. You will also need a few brackets for the tb and cables etc so have a word with GDI.

 

[mattjk]

Try giving the Tb a clean first (unless youv done ths recently?)

 

[LeeJSA]

Loom afaik should remain the same. Might as well buy an omex ecu as you will be needing that for your tb setup anyway. You will also need a few brackets for the tb and cables etc so have a word with GDI.

Already got Adaptronic ECU for the tbs.

Try giving the Tb a clean first (unless youv done ths recently?)

Already cleaned it mate - but its not that anyway.

 

[bmh.01]

Pedal first port of call, 3krpm idle is default when the ECU can't "see" the pedal when its doing it if you hold the brake pedal down does it drop to a normal idle?

 

[LeeJSA]

Pedal first port of call, 3krpm idle is default when the ECU can't "see" the pedal when its doing it if you hold the brake pedal down does it drop to a normal idle?

Aint tried that - will give it a whirl next time I'm at the car - knowing my luck it will just start & run perfectly though next time try it!!