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Over-revving and high idle on Mk1 Focus

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Old Sep 21, 2010 | 07:04 AM
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Question Over-revving and high idle on Mk1 Focus

Hi guys,

For about 3 months now our 70k mile 2002 1.8 Zetec has been exhibiting some irritating an dangerous characteristics.

For instance, if you want to use the gears to slow down, the revs rise to meet the road-speed, but fail to drop and thus you don't slow down. I think related to this is: If you're coasting up to a set of lights with the gears in neutral and you rev the car to a peak of 3k, the revs will sit at ~3k until the car has stopped completely at the lights.

I have replaced the Idle Control Valve and reset the ECU (which cured it for about 3 days!) but it seems to have come back and I'm at my wits end!

Any clues as to what might be the problem?

TIA.
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Old Sep 21, 2010 | 07:23 AM
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I would be looking at the VSS (Vehicle Speed Sensor) sometimes the speedo will go funny as well.

Martin
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Old Sep 21, 2010 | 08:38 AM
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Thanks for that Martin! Where can I find the VSS? I've not had any problems of note with the speedo?

I've literally just been speaking to a work colleague who mentioned cleaning/ replacing the Mass Air Flow Meter and/ or replacing the Throttle Potentiometer. Would faults in either of these cause the symptoms I'm experiencing?

Last edited by Nero; Sep 21, 2010 at 08:43 AM.
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Old Sep 21, 2010 | 12:53 PM
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I wouldn't think so if it were you would have other problems with driving it that being said the Mass airflow sensor is known for 'Gumming up' after a while this normally shows around 4K RPM it is easily sorted by cleaning it, although you do have to be careful as the wire is delicate.

The VSS is located on the back of the gearbox.

Martin
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Old Sep 21, 2010 | 01:45 PM
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yep vss would be the first thing to change imho. after that i'd try the tps (throttle possition sensor). doesnt sound a maf related problem though.
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Old Sep 21, 2010 | 02:00 PM
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Great advice, thanks chaps!

Just got a Genuine Ford VSS for £30 from eBay (bargain?).

Finger's crossed it alleviates the issue(s)!

Last edited by Nero; Sep 21, 2010 at 04:21 PM.
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Old Sep 22, 2012 | 07:13 PM
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Originally Posted by Nero
Great advice, thanks chaps!

Just got a Genuine Ford VSS for £30 from eBay (bargain?).

Finger's crossed it alleviates the issue(s)!



hello fella did that solve your problem ??
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