High idle?

[Kjakk]

Yesterday I started my car and right away the idle went to about 2,000. It stayed there for about 4 minutes. I tapped the gas a few times but it had no effect. It went down and I drove the car for about an hour and everything was fine. What might cause this?

Thanks

[pitstoppete]

idle is coolant temp. dependent iirc.

mine too does this sometimes. it goes down to normal soon after.

[lrg_machine]

EBPV and throttle jack?????

Are these still on the car?

[fmxa]

It's normal - mine sometimes does it when it's cold (although not always!) it's something to do with emissions and warming the cats up ....

[Paul93Lotus]

According to the EFI portion of the Esprit Service Notes, this is part of the warm up procedure. The jacking solenoid bumps idle above 2000 rpm, and closes the EBV (exhaust Bypass valve) to create more exhaust back pressure. This heats up the catalytic convertor quicker and brings the O2 sensor up to temps quicker in order to lower emissions. You can bypass the high idle if you give the gas pedal a quick jab more than 50%...this will disable the jacking solenoid routine and return the idle to approx 1200-1500 rpm until the coolant temp reaches a predetermined temp. At that point you will get your normal 900-1000 rpm idle.

If this is too annoying, I believe you could disable the jacking solenoid by removing the vacuum line that runs to it and plugging it.

[Backmarker]

My S4 also suffers with this problem from time to time.

Whilst I've tried jabbing the throttle it doesn't always work for me. What does work though is pulling over, switching off and re-starting the engine. Don't know why but it works every time for me.

Graham.

[Kato]

The throttle capsule can get sticky and give you a high idle. It happened on LEW's car over a year ago. It just got worse and worse and happen more often, until we fixed it. See LEW's guide here:

http://www.lotusespritworld.com/ETechnical/EBPV.html

[CarlC]

If this is too annoying, I believe you could disable the jacking solenoid by removing the vacuum line that runs to it and plugging it.

<{POST_SNAPBACK}>

I've totally stripped all this crap of my S4 and it still goes into high idle some times for a while after first start up. But as Graham(Backmarker) says, my is the same switch off and restart the ignition and it settles down. Im sure there some reason that the car does this even with the TJ/EBPV removed but its still annoying. The cat warm up is the most likey explanation but my car will do this some times even after a few minutes of spirited driving when you expect the cat to be warmed up. However I dont get the 2000 rpm more like 1200+ rpm.

Ill be interested to see if the car still does this with a new chip in it.

[Dermot]

Carl,

Idle is controled by initial coolant temp. The calibration table that controls this is on my site.

http://users.ox.ac.uk/~ohare/ecu_tables.htm

See table

Target Idle _ RPM vs Coolant

You are right to junk all the other wiggets.

Dermot

[Vulcan Grey]

After disabling my throttle jack (EBP has been out of the car since before I bought it) br removing the electrical connections, I still ocassionally got a high idle, especially after getting off the highway. My throttle jack hinge was sticking. So I removed the whole thing.

As Dermot and others said, the IAC valve will still provide a high idle under low coolant temp conditions.

Thanks for the tables Marcus and Dermot.