Engine Revving Very High In Idle

[dgriff]

Hi
I have a 406 1998. Sometimes (50% of the time) the engine idles between 3,000 rpm and 4,000 rpm. And when it's idling up here I'll turn the engine off and start it up about 5 more times before it settles down to around 900 rpm.

When I drive it when it's idling very high when I put my foot on the clutch to change gear the revs increase instead of decreasing. The revs only get under control when I have it in gear. I dont think the throttle cable is getting stuck because when it idles very high it's as if someone is putting their foot on the accelerator and revving it even higher.

Anyone got any ideas? Thanks.

[john_h]

your best bet to pin point the problem is to get it hooked up to planet to test everything to see what is up

[Scotcruz]

Originally Posted by dgriff

Hi
I have a 406 1998. Sometimes (50% of the time) the engine idles between 3,000 rpm and 4,000 rpm. And when it's idling up here I'll turn the engine off and start it up about 5 more times before it settles down to around 900 rpm.

When I drive it when it's idling very high when I put my foot on the clutch to change gear the revs increase instead of decreasing. The revs only get under control when I have it in gear. I dont think the throttle cable is getting stuck because when it idles very high it's as if someone is putting their foot on the accelerator and revving it even higher.

Anyone got any ideas? Thanks.

with the engine off, check to see if the rev cable is running freely.. it may be seized.. its behind the air filter assembly and a black plastic circle thing with cable round it.

[dgriff]

Originally Posted by Scotcruz

with the engine off, check to see if the rev cable is running freely.. it may be seized.. its behind the air filter assembly and a black plastic circle thing with cable round it.

It's running freely.
I just noticed a loose clip. It's a round clip that goes around a tube.The tube is a black tube that runs from the engine block and ends in the big black tube that runs into the box where the air filter is. (but before it reaches that it also branches off into the black plastic circle thing) It's just to the right of the "black plastic circle thing with cable round it" that you mention above.
I tried to clip it back with my hand but I'll have to root out my leatherman to try to tighten it back on to see if it makes a difference.

[Scotcruz]

Originally Posted by dgriff

It's running freely.
I just noticed a loose clip. It's a round clip that goes around a tube.The tube is a black tube that runs from the engine block and ends in the big black tube that runs into the box where the air filter is. (but before it reaches that it also branches off into the black plastic circle thing) It's just to the right of the "black plastic circle thing with cable round it" that you mention above.
I tried to clip it back with my hand but I'll have to root out my leatherman to try to tighten it back on to see if it makes a difference.

hmmm... its deffo to do with EGR mate... check all the pipes.. Typical gas circulation

[dgriff]

Originally Posted by Scotcruz

hmmm... its deffo to do with EGR mate... check all the pipes.. Typical gas circulation

I checked all the pipes and they seem fine. Any sensors I could check?
Still revving very high but just noticed today it only starts to rev high after I bring the revs up over 2,500 rpm. If I keep the revs low by keeping it in a gear higher than it should be for the speed I'm doing, the revs seem to stay under control. But driving like this I only use a tiny bit of acceleration. Any more and the revs get out of control.