Ford fiesta - engine revving very high

hi all,

I know this is not a mechanics website, but maybe someone out there might be able to help me.
Driving a 1997 Ford Fiesta 1.25l zetec engine, 51k miles. With the last 2 months or so, about 2/3 times a week, when I start it up, the revs go nuts, up to 4,000 rpm without my foot being near the accelerator! Doesn't come down either until I move off. If I have to stop again (say at traffic lights or whatever) within a minute or two of take off then it starts revving like crazy again. Took it to garage but it was having a 'good day', and wasn't revving. Mechanic said there could be a sensor gone. Problem is, by the time I get to the garage (about 10 miles away) the car has stopped doing it. So, in brief, it stops turning over so fast if I have been able to drive pretty much without stopping for 5/6 miles, but if I get stuck in traffic it will stay ticking over at a very high rate. It has an automatic choke. I sound like an old biddy whose driving in 2nd gear the whole time!
I've always thought that the engine ticks over quite fast, and have gotten it tuned etc. before, but it was never as erratic as it is now.
Has anyone else had similar problems? would a ford garage/main dealer be able to 'plug it in' to the computer and tell me what's wrong, even if I took it on a day when it was not revving mad?
any ideas appreciated, its really p**sing me off at the moment!
thanks.

Hi Boogaloo


I had the same problem with a Seat Ibiza and I was told it was the spark plug leads and that it wouldn't cost too much to fix. I was getting rid of it anyway so didn't bother getting it fixed.

When was the last time the car was serviced?

Could also be the accelerator pedal/cable sticking.

hi Kiddo,

unfortunately I am not getting rid of mine
I'd only be able to sell it on a day it was behaving anyway, no one would take it when its doing its airplane taking off noise.
Funny thing is, all this only started because I got the spark plugs changed. 2 sets put in, turned out that one set were faulty so I had to get them replaced on a different day. I wonder should I change all 4 plugs again and see if that would help?

Boogloo,

Interesting to read this post as I have also experienced the same type of problem. Car is Fiesta '97 Encore, 1297cc, mileage ca 82K. Most immediately the engine revs alarmingly when the clutch is engaged. Otherwise the problem is as exactly described on your post. Prior to service I suspected the clutch plate was slipping, however the mechanic informed me that he had driven the car and, (from what I could gather) that a sensor detecting clutch engagement was faulty. Anyway, the sensor was replaced and the problem disappeared for about 10 months. The car is now due for the annual service - which is why I noticed this post - and the problem reappeared about two months ago.

hmm, interesting Balga. Do you mind me asking how much it cost you to get the sensor replaced? It does indeed get worse when I engage the clutch, sounds like both of us have had/have the same problem.

Quick Google turned this up.

I am reading the service invoice. It is dated 06/05/03 so the replacement sensor was fitted over two years ago. Total cost was 146.88E (inc VAT) which included labour for test drive. The throttle sensor was faulty and needed to be replaced. This sensor is a type of potentiometer and was listed at 42.91 ex VAT. Rest of invoice was largely labour, so cost will be reduced second time around. Finglas Ford serviced the car.

I can't seem to access the thread from the previous post right now, but my Fiesta is also manual steer so it does look as though the problem with your car is a faulty throttle sensor. Having identified the problem you might be able to get away with fitting a replacement for under 100E.

FYI
The car will be serviced in the next few weeks and I will have to get the sensor replaced.

Balga,


you were spot on! Faulty throttle sensor. Only got around to getting something done about it this week, have been driven mad by it with the last while. Ford garage had to order in the part so it won't be actually fixed until next week. I was hoping to try + go somewhere else to get it fitted (and not have to pay the incredible 72 euro an hour + VAT for labour), but was told it needs to be calibrated by the diagnostics machine once the new sensor is fitted.

thanks for advice, although I'm a bit concerned that yours went again after 10 months...

As an aside, does anyone know what VAT rate should be charged on garage labour? I thought it was 13.5% but paid 21% today......

I have just read the thread and I am having evactly the same problem as you guys, interestingly with a 1997 ford fiesta 1.25 with the zetec engine. Not only is it extremely frustrating, it is also quite dangerous - there is no engine breaking through the gears and the car generally stays at the same speed with no decelation at all when the throttle is released, it's as if it has cruise control. In traffic the car lunges forward as the revs are so high. A flat spot under acceleration has also got really bad - the car has only done 36,000 miles. I read on another website that it may be the mass air intake sensor located near the air box as this sometimes get choked with grease. I unplugged it and took the car for a spin. The difference was amazing and I had my old verry nippy zetec back. Except the problem wasn't solved as the car won't idle and cuts out unless constantly tapping the accelerator, even at a standstill. I was going to replace the mass airflow sensor for £70 but now I'm not sure!?!? Any thoughts??

Go to a main dealer. Plug it in to the diagnostic gizmo.

It's probably a TP sensor.