Idle High

[carob]

Just had the wedge out today for the firt time this year. and the idle was running high at 1500 when i started up then after about 10 mins dropped to 1100 then fluctuated between the 2 figures.

Any ideas chaps

Rob

[honestjohntoo]

carob said:

and the idle was running high at 1500 when i started up then after about 10 mins dropped to 1100 then fluctuated between the 2 figures.

Not un-typical after a winter layup to have such a problem of a raised idle speed but not usually accompanied by the rarer hunting as reported, so I'm wondering if you have reported all the accompanying symptoms along with identifying what type of fuel injection system is installed.

The reason I prompt for more info is, one might expect that your problems as reported would be accompanied by at least one other symptom, namely an inability to generate any power and readily stall under load.

If so, it sounds like a combination of two problems.

• a small amount of idle speed hang-up holding the throttle plate slightly open, typically caused by sticky throttle mechanicals or some dirt thereabouts preventing the throttle from closing fully - that's a common thing after a lay-up.

and

• a rogue air leak into the main input tunnel allowing un-metered air into the system or possibly into the plenum chamber or via the breather system.

The former would account for the unexpectedly high idle speed, even when warm, and the latter would account for the varying idle speed accompanied by a lack of torque under load.

Indeed, even the effort of turning the engine is creating a stall situation such that the engine tries to die at the higher rpm (1500) because the mixture there is at it weakest, but catches again on the way down as the rogue air proportion lessens, and the mixture richens-up enough to prevent the stall actually occurring.

This type of hunting is not to be confused with the classic RV8 Efi hunting syndrome which is actually rooted in a slightly rich mixture during warm-up at lower idle speeds.

Edited by honestjohntoo on Thursday 17th February 19:53

[carob]

Yes there is a kind of lag in the power distubution, if thats the correst way fo put it.

It is a flapper system

Rob

Edited by carob on Thursday 17th February 21:04

[HOTTY]

Hi Rob

Have you been out on a run ?

Has that made any difference, if its only just appeared and you have not completed any work in the engine bay, it must be down to a part sticking.

Hopefully you find the problem soon

[400SE Dave]

Engine temp sensor????

[dixiebabes]

A Potatoe in the exhaust could also be the problem.

Dix

[convert]

dixiebabes said:

A Potatoe in the exhaust could also be the problem.

Dix

Obviously Rob can't be Latvian then

[honestjohntoo]

Flapper! OK! Winter layups also cause connector corrosion problems around the vulnerable Efi system, so - for example - the suggestion of temp sensor is partly valid.

Not the sensor itself - why would it just fail - but its associated connections to the ECU and the earth studs at the back of the block.

While you are at it check, clean and protect ALL Efi connectors.

[carob]

Had a fiddle with most components mentioned, nothing major just made sure everything was clean and fitted corectly and tight, took the wedge for a good blast and now sitting on a constant 1000rpm.

Thanks for all advice.

Rob

[dixiebabes]

Like most wedges the only listen to you and start behaving after you have kicked its head in for an hour!!!

Dix

[tony350i]

dixiebabes said:

Like most wedges the only listen to you and start behaving after you have kicked its head in for an hour!!!

Dix

i like that lol,


Mine passed its mot a couple of days ago and the harder I kick the better the car feels and behaves

[Wedg1e]

carob said:

Had a fiddle with most components mentioned, nothing major just made sure everything was clean and fitted corectly and tight, took the wedge for a good blast and now sitting on a constant 1000rpm.

Thanks for all advice.

Rob

1000rpm seems a bit high to me, unless you have a cam with lobes like Jordan...

[Campbell]

Carob if the car has been sitting for some time it will need a few mile to clean hear out, have you tried any carb cleaner and vaseline on the electric plugs.
A 1000rpm isnt to bad, the SEAC has a Jordan special in her and wont tick over under 1000rpm, still you could give the allen on the plenum a we turn to drop the idle when hot or leave it.

Cambelt