Mk I Mondeo idling problem

Check the 2 wires to the PSPS on top of the engine towards the bulkhead- they often rub on the underside of the bonnet and break. An open circuit will result in a constant stuck high idle (~1100rpm) as the ECU thinks the steering is constantly in use.

Tim..

Thanks Tim, I'll check the wires as that's not something that has failed yet... The engine idles between 0 (i.e. it's stalled) and 1,500 - but normally swings between 300 - 900 making it interesting in stop/start traffic. Jon

Ahh, I thort idle was stuck high.

In which case look for a vacuum leak (again) or your looking at a sticking ISCV.

Tim..

Thjis might sound like a stupid question, but can the valve be unstuck? I'm olny looking to do less than 1000 miles in the car before I replace it. Thanks, Jon

Ah! throttle body cleaner...... Jon

Indeed!

If you remove the inlet hose and air box thing ontop of the throttle body to reveal the butterfly you can clean this area with a damp cloth (of carb cleaner) jam the butterfly open and clean the area immediately behind it, where you will probably feel a ring of carbon. An old tooth brush is a good tool for this job.

You will also see a passage way which leads down to the ISCV valve (under the manifold and a pig to get at) if u give this a goodly squirt and leave to soak for afew minutes where it will have trickled down to the valve below. I have had some success on mild stickings of ISCV's with this method, you cant do any harm. Refit the inlet hoses and do up the jubliee clip and start the engine- may require some throttle. Let it idle for a minute or two, then remove the inlet hose again and squirt some more carb cleaner down the passageway. Let it sit again for alittle while before starting the engine again.

This may help. If its no better, then you're going to have to bite the bullet and remove the ISCV for a proper cleaning, or replacement.

Tim..