Engine revving high at idle

[dkmech]

Peugeot 106 1995 1.1 petrol injection.

For the last week its been revving really hard at idle, and not just when i start it up. After a fair amount of driving too. I thought it might be trying to warm up to decent temperature as its been a bit chilly, but i am not sure. Don't know what the exact revs are coz i don't have a rev counter, but i'd say 3-4k.

Any ideas?

[schrickvr6]

Have a look under the bonnet and see if the throttle linkage is returning to fully closed, if not lube it up with a bit of spray grease and also spray plenty down inside the throttle cable sheath, otherwise i'm not sure, but it could be something like a dodgy idle stabilisation valve. (if they have one)

[[GSV]Trig]

ICV i there is one or maybe a split in a rubber inlet pipe somewhere...

[Butuz]

Also check you havent lost any engine coolant - i had a water leak and my car revved high (2000rpm) constantly before overheating.

Butuz

[dkmech]

Right, i checked engine coolant and it did need a top up. It didn't rev high after i did it, but its 12 degrees today rather than near 0 as was in the last couple of days.

The throttle cable seems fine, i am pretty sure its not the problem as when i am driving it doesnt stick or anything.

I'll see if its the coolant after its been driven for a bit.

Cheers for your suggestions guys.

[Rave]

Might be an air leak somewhere in the induction system?

Rich :¬)

[Konan555]

Right,

Firstly, like rich says, it sounds like air leak. However, at 3-4KRpm, if nothing's fallen off you'd probably hear a large air hiss from the induction. Go round any joints in the air system and give em a quick WD40 whilst listning for a change in the idle.

If it's not that, it could be your ISCV is jammed open, take it off and give it a complete clean with carb cleaner.

You may also want to try reset your base idle.

Now I'm not sure about the speicic management on frog-mobiles, so this is the 'generic' method.

Disconnect the negative lead from your battery for a good 10-20 minutes (should reset the KAM in the ECU) This isn't 100% vital

Disconnect the wires from your ISCV and TPS

Reconnect the battery

Start the engine and adjust the idle on the throttle bodies (if you can't get the idle down to normal you've REALLY got an air leak or the ISCV is totaly jammed)

Reconnect the TPS and the ISCV one at a time, if either of these causes the idle to bounce up, there's your problem.


EDIT: I meant throttle body, I assume the 1.1 unit isn't a V8

[dkmech]

Sounds great. Although about 80% of that made as much sense to me as it would to Mr H.J. Simpson.

Its been working fine after i added some more coolant.

Thanks for taking the time for such a detailed explanation. Although a mechanical engineer I'm afraid i am not yet intimate enough with my car to do more than a change of air filter and maybe spark plugs. But big thanks none the less.

[Konan555]

Ah right,

None of that would take long to explain anyway, it's all stright forward stuff.

Just gimme a shout if you have any more problems and want to try it.