Fiest 1.25 16V Zetec returning to idle too slowly.

Apologies, from a google search this might be a FAQ but I've just got a 70k

1998 Fiesta 1.25 16V Zetec and it doesn't like returning to idling speed when pulling up to junctions, roundabouts etc. It gets there eventually but might take a few seconds and/or a push up on the bottom of the gas pedal with my foot (which you can't really do if you're braking!). Otherwise it will just wander between 1000 and 2000 rpm. Possibly more if the engine has been at high revs for a while first.

I've read suggestions about Throttle Position Sensors but wondere if anyone else had any other pearls of wisdom about this? It's one of those problems that is entirely livable with but it rather annoying. The car otherwise drives perfectly. It has power steering and aircon if that is relevant although the problem happens with or without the aircon switched on.

Thanks,

Tony

Reply to
Tony Brett
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if lifting the pedal slows it down at all then the cable is adjusted too tight.

mrcheerful

Reply to
mrcheerful

I actually happened to come across the Ford techincal buletin for this a couple weeks ago. First thing is to check is that the mechanical bits of the throttle are working correcly, and returning freely (ie. cable adjusted properly, and throttle valve returning quickly). Failing that, there's a known fault with the idle control valve and wiring. You're supposed to replace the Idle control valve and solder in a new connector for it. If you want all the details, I'll see if I can find the buletin again.

Reply to
Moray Cuthill

Only works sometimes... But I'll check that. Thanks.

Tony

Reply to
Tony Brett

In message , Moray Cuthill writes

Are you sure you are not referring to the TSB on the TPS which required a new TPS and connector to be fitted. This wasn't on the 1.25 Zetec though. It was on the 1.3 Endura.

Reply to
Paul Giverin

OK - I've done some more investigation today and it seems that the over-rev is related to road speed. If I get to say 30 mph and then depress the clutch and take my foot off the accelerator the revs stay around 2000 rpm until I bring the car to a halt. Then they drop.

I've had the throttle cable right off and made sure it and the throttle valve all operate and return freely and they indeed do.

I read a web posting somewhere (not usenet, lost the URL now) that said the problem can be caused by the road speed sensor and suggested just disconnecting it. I've done that and the problem is completely cured. The haynes manual says this sensor is used to help the powertrain control module control fuel shut off on over-run etc. so my question is, will running without the road speed sensor cause any damage (to the cat?) or excess fuel consumption? Of course the original problem can't have been doing a lot for fuel consumption!

I'd be pleased to hear from anyone with any experience of this and Moray, I'd be delighted to receive the details of the Ford Bulletin about the idle control valve if you have them. Note the need to remove "Removetodespam" from my E-mail address if replying privately. Reminder - it's a 1998 1.25l Zetec-S 16V engine.

Cheers,

Tony

Reply to
Tony Brett

Hmm. You'll be able to tell us if it makes a difference to fuel consumption. However, personally if it were me, I'd not remove a sensor. It's there for a purpose of course.

You could ask your dealership for help on this?

Either / or, it sounds like it could be the idle control valve, which will need cleaning. There's some information on the ICV on my website (yeah it's a different car and engine but the technology is remarkably similar), or the throttle position sensor may need replacing.

Reply to
DervMan

Had the same problem on my wifes Fiesta 1.25 zetec etc. Replaced the ISV (circa £25 from Ford dealer) solved the problem immediately. Tried cleaning tec. but did not solve the problem.

Reply to
JonE

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