High Idle

[Darren C]

Hi,

Been out in the D today but the idle speed will not drop below 3000RPM!

Even when hot.

Mechanically theres no jam, throttle linkage free, seems electrical?
Any ideas.

Took battery on and off, started and stopped, still 3000rpm?

Hot or cold still 3000rpm,

Please help as it's an interesting drive, and I cant afford the fuel!!!

Best regards
D

[Chris P]

It sound like one for Nick T or Richard H, however, I'd try just removing the air cleaner and see if the round alloy flappy thing is stuck.

[Conor Doyle]

Hi Darren,

It sounds like your throttle cable has come off the spool, and is not alowing the spool to engage the idle speed micro switch.
This is usually caused by turning the spool by hand to rev the engine.

Hope this helps.

Conor

[Dodgy Motor]

Darren after checking the throttle spool and that the "alloy flappy thing "
or air flow sensor plate, is closing
item 10 is the idle speed control valve, it is possible it has stuck, this happend to mine, give a firm but not to violent thwack with something metalic, i.e. a spanner of toffee hammer , :wink:

[Darren C]

Thanks Guys

I'll check it out tomorrow evening after work, and when I've put my rear Spax Shocks on.
I stripped the rear suspension down this afternoon.
Shocks arrived last week, and yes I did paint them Blue Grey!!

Thanks again I'll let you know how I get on.

Best regards
D

[NickT]

Try what Dodgy Motor suggested first.

Another thing to test is put the ignition key to position 2 then feel the idle speed control valve. It should be humming slightly. If not then check fuse 1 is ok and that both white plugs are plugged into the idle speed ecu (no.1 is Dodgy Motors parts picture.

Failing this, it could be:

throttle switch is not working
throttle switch is not being operated when foot is off accelerator
cable unwound off throttle spool making it not fully (causing above)
thermistor has gone open circuit
the Thermistor plug has fallen off the sensor
ECU has incorrect signals/ voltage levels to/from it
the ECU is duff

Hope this helps

Nick

[Tourettes Tony]

love the moving avatars nick :lol: :lol: :lol: :lol: TT

[NickT]

[Darren C]

Hi Nick T, and Dodgy Motor,

"Another thing to test is put the ignition key to position 2 then feel the idle speed control valve. It should be humming slightly. If not then check fuse 1 is ok and that both white plugs are plugged into the idle speed ecu (no.1 is Dodgy Motors parts picture."

HUMMING FINE, FUSE 1 OK, GOOD THWACK AND NO DIFFERENCE.

Failing this, it could be:

"throttle switch is not working "

TESTED MICRO SWITCH WITH MULTIMETER FINE (with cables removed)

"throttle switch is not being operated when foot is off accelerator"

SWITCH OPERATES WITH FOOT OFF ACCELERATOR

"cable unwound off throttle spool making it not fully (causing above)"

CABLE FINE

"thermistor has gone open circuit"

WHERE'S THE THERMISTOR? ON THE BULKHEAD IN WHITE?

"the Thermistor plug has fallen off the sensor"

AS ABOVE

"ECU has incorrect signals/ voltage levels to/from it"

OK THIS IS WHERE IT GETS COMPLICATED...WHAT SHOULD I HAVE HERE?

"the ECU is duff"

Reading through the forum there was an engine hunting problem that was ECU in the end. Curiously ever since I have had the car (Imported Sept 07) the engine hunted at idle quite bad until it warmed up, that faults now gone, and's replaced itself with this high idle.

Looks more and more like ECU?

Where can I get a new one/repair?

Oh and yeah while checking your list, FLAPPY THING FLAPPING, AND FLUX CAPACITOR ER....FLUXING!

Best Regards
D

Hope this helps

[bozzzydmc]

Hi Darren

My 2p worth.

Check to see if the 2no butterfly valves in the throttle body are closing properly, if you take off the arm from the throttle spool ( remove the little circlip) to see if it springs back closed any more.

[Dodgy Motor]

Darren .The thermistor is item 31 on the above pic

[Darren C]

Hi,

I was kinda hoping you wouldn't say item 31.

Cos it aint here!

Searched my parts CD too and states constant idle thermister No 31.

But not on my car????

I have two white connector plugs in the loom just by the Throttle spool cover, they contain two pins each.
One is in use but the other has no female plug and is flapping in the wind. (colour Green/blue stripe & Black). Theres nothing to plug it into?

On the intake manifold in the drawing there is no boss for item 31?
Just three brass plugs in a row. The Front one is by the microswitch, with a screwdriver slot and blob of green "factory" paint (so it's never been out) the other two plugs are in the vertical plain with hex heads.
None of this is in the drawing?

Any clues?
Should I have something to plug in this "spare" connector? (judging by the oil residue in the plug, nothings been plugged into it for a long time?)

Is this just a wild goose chase as apart from the previous hunting issues the idles been fine in the past?

So many questions!!

Best Regards
D

[bozzzydmc]

Its not very clear but this part is actually in the y pipe under the intake manifold.. without it you will have a major source of coolant leak

[Dodgy Motor]

well if your sure it doesnt have one and never had one, its not that :lol:
just asking did you check the throttle butterfly as Bozzy said?
If it were me I would still be looking at the idle control valve, it may be stuck open or not being controlled properly,

[bozzzydmc]

Darren C Wrote:Hi,

I have two white connector plugs in the loom just by the Throttle spool cover, they contain two pins each.
One is in use but the other has no female plug and is flapping in the wind. (colour Green/blue stripe & Black). Theres nothing to plug it into?Should I have something to plug in this "spare" connector? (judging by the oil residue in the plug, nothings been plugged into it for a long time?)

Is this just a wild goose chase as apart from the previous hunting issues the idles been fine in the past?

So many questions!!

Best Regards
D

Do you have an auto ???