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Over revving when first starting the car

Posted: Tue Jan 11, 2005 1:28 pm
by DaWeapon
When i start my car, and drive along for a bit, the revs seem to stick at about 2000 revs. Its only after i am stationary for a bit will they drop down to normal idleling speeds 7 -800 rpm. I seem to cure this prob by turning the car off and then turning it back on again.
How can i fix this problems and what is it?

btw Its a 1991 V8 EFI 3.5 Litre Disco.

Posted: Tue Jan 11, 2005 3:45 pm
by malibu9
Maybe the auto choke is sticking on.

Posted: Tue Jan 11, 2005 4:05 pm
by DaWeapon
Where would i find this in the engine bay?

Posted: Tue Jan 11, 2005 4:59 pm
by Rovernaut
Being an EFI it could be the stepper motor ( IAC) this controls idle.
They gunk up with carbon, you will find this at the rear drivers side Plenum chanber. It has wire plug going into it.
Unscrew it and give it a good clean with carby clearer and refit..Also spare inside the housing it connects into.
DON"T MUCK AROUND WITH IT AND TRY TO UNSCREW THE NEEDLE AS YOU CAN DAMAGE IT> It is actually an eletromagnet motor.
Also throttle position is controlled by a throttle potentometer on the neck of the plenum chamber air intake. Itf this is faulty then it can also cause high idle.

Posted: Tue Jan 11, 2005 5:00 pm
by Rovernaut
malibu9 wrote:Maybe the auto choke is sticking on.

EFI don't have chokes. it is all computer controlled by the ECU