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1993 Mitsubishi 2.0l petrol - fast idle problem

Hi there

I have a 1993 Mitsubishi Spacewagon with the 2.0l petrol engine that was also used in the Galant amongst others.

The problem is with the idle speed of the engine when the car is braked to a halt - it sticks at about 1500 rpm for 30 seconds or so and then drops to normal. Revving the engine with the car stationary does not replicate the problem.

I'm thinking - therefore - that it's something to do with an engine sensor or vacuum pipe that is taking a while to return to it's zero mph setting. I've cleaned up all the wires, connectors and pipes that I can find, checked the throttle cable and so on - no joy. Can anybody point me at a possible cause/solution? (I'm still awaiting a Haynes manual that I've ordered)

Thanks

Graeme

Reply to
Graeme
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Was the battery disconnected recently. I had a Galant that did something similar for a day or two if the battery went flat or was disconnected. It always sorted itself out after a couple of days.

JOhn

Reply to
John

Hi John

I'm afraid not - I've had the car for two weeks now and the battery has always been connected.

Reply to
Graeme

Must be a fault with the idler motor or potentiometer. There is a closed loop system between ECU, idler motor and throttle potentiometer. If you disconnect the wires to the potentiometer and measure the resistance with a multimeter you should see a steady increase/decrease as you move the throttle.

John

Reply to
John

Check the connections to the Vehicle speed sensor on the gearbox, and if they appear ok, check for out put from it with a DVM- jack up one road wheel so you can spin it.

This is whats causing your sticking high idle- the ECU still thinks the vehicle is moving..

Tim..

Reply to
Tim..

If that was the case, the speedo'd be staying up too wouldn't it.

John

Reply to
John

No doubt it. Speedo is driven mechanically on on the spacewagon.

Tim..

Reply to
Tim..

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