high idling speed when cold

[rowald]

Hi,
I own an 93'4.3 Griffith. Since several weeks the idling speed is above 2000 when the engine is cold. Once I start driving, after several minutes it sometimes drops lower (kangaroo-ing) and once the engine is hot it runs very smoothly and has the normal idling speed. Also restarting the hot engine provides normal idling speed. Offcourse I cleaned the stepper motor and the butterfly valve. It looks like one of the sensors is not providing the correct signal.
Any suggestions for a solution?
Many thanks,
Rowald Pouderoyen
Netherlands

[Colin RedGriff]

Sounds like something is up with the cold running. When you cleaned the stepper motor did you also clean the housing that the stepper motor screws into.

Check that the stepper is moving in and out. Connect the stepper wires while it is out and turn the ignition on and off, you should be able to see it move.

I would get hold of a copy of roverguage and a cable to connect it to the diagnostic plug (blitzracing on here can sell you one) that will let you see what is happening while the car is running

[Steve_D]

Colin RedGriff said:

.....I would get hold of a copy of roverguage and a cable to connect it to the diagnostic plug (blitzracing on here can sell you one) that will let you see what is happening while the car is running

OP
You may not be aware RoverGauge will show the coolant temperature and fuel rail temp so it is very easy to see if a sensor has failed. You can check this just by plugging RoverGauge in with a cold engine. You can easily establish the ambient temp and compare it to the readings on RoverGauge.

Steve

[rowald]

Thanks for the input. I had the equipment connected, and one of the lambda sensors appeared to be defactive. After replacement the engine runs smoothly again.
Rowald