Lotus Idle

[blackjack]

Anyone out there got any ideas on the following...

I have a Lotus Elise 2002 which drives me nuts with its idle speed.
Been like it for about 2 years and even Bell & Colvill can't seem to solve the problem.

Basically, the engine does not sit at 900rpm when standing, it jumps up and down from 500rpm tp 1200rpm. Drives great...but this is just bugging the crap out of me!!!

ECU's etc have all been checked, manifolds the lot!

[dern]

The first thing I'd check would be the idle control valve but I can't believe your dealer wouldn't have done the same.

[kambites]

Mine (a 111S so slightly different engine) doesn't idle particularly smoothly. It jumps around between 1000 and 1200 rpm when cold and 850 and 950rpm when up to temperature. Doesn't seem to matter though.

[blackjack]

Dern, that's been replaced and checked at least a couple of times. Any other ideas?

[L100NYY]

It'll be down to the battery having been run down too low at some point, consequently jump started and the revs are hunting as the ECU needs to re-learn. It should be easily curable either with a good charge or a new battery and a change of idle valve.

HTH

[Sam_68]

As Dern says, IAC valve or wiring would be the first suspect, but if you are confident there's no problem there, check to ensure you have no air leaks on the inlet manifold and that the throttle body isn't sticking slightly.

[rfoster]

Might sound obvious but I had a similar problem with mine recently, hunting instead of idling. It was a simple matter of adjusting the idle screw on the throttle body to bring the revs up to the correct level - mine was set too low so the butterfly closed too much and resulted in a too low idle. My ECU (Emerald) then adjusted fuelling to compensate (up to 1,300 rpm) and this caused the hunting. 1/4 turn of the screw and it was perfect.

Alternatively it could be your TPS.

[kahuna]

Funny that, mine (2002 S2) does the same since I bought it 2 years ago.
Its only for the first minute after starting it, after that its fairly stable, may jump around 100rpm or so.
I thought it may be the idle control valve, but I've just learnt to live with it so I've left it as is.

[RobM77]

On another note, does anyone here find their idle too low? I've got a VVC engined 111S and it idles at about 800rpm, which means you've got to raise the revs quite a bit to pull away and it also makes strange noises at 800rpm that it doesn't at a more normal speed of 1,000rpm. Bell and Colvill and Plans Motorsport have looked at it and reported it to be normal.

[Concerned cat]

You do know that they are equiped with an anti stall thingumy? Basically if you're rolling forward the idle speed increases. When you come to a standstill, the idle speed drops.

HTH

[RobM77]

Concerned cat said:

You do know that they are equiped with an anti stall thingumy? Basically if you're rolling forward the idle speed increases. When you come to a standstill, the idle speed drops.

HTH

Not sure mine does! It's really easy to stall it.

[blackjack]

Tend to agree.......very easy to stall!!!