Fiesta Zetec hot idle
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Fiesta Zetec hot idle
1 June 2009, 4:40 PM
 Edited by topmansparkie 1 June 2009, 4:44 PM
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topmansparkie
Joined 1 Jun 2009
3 posts
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Hi All. I am sorry to drag up another discussion regarding idling issues with the Zetec. I have trawled the past discussions but haven't really found anything specific to my problem.Fiesta 1.25 Zetec-S, 'N' registration, Manual transmission, Petrol. Starting when cold:
Starts first time. Idle speed sits around 1400 RPM and lowers to 1000 after about 3-4 mins. Drives like a dream. When engine has warmed up (temp needle sits at the letter 'O' on the word 'NORM' on the temp guage):
With the clutch pedal down, the revs hunt from 1000 RPM down to around 500 (almost stall and car judders) and back up again to 1000. The revs will hunt up and down until I let the clutch pedal back up.
The engine hunts irrespective of what gear I have selected or whether there is road movement or not, as long as the clutch is down. I have changed/replaced the following:
Throttle position sensor - new part from Ford
Idle control valve - new part from Ford
Oil
Spark plugs
Air filter
The Mass Air Flow Sensor looks new as it is shiney silver and clean inside. I have cleaned the throttle housing and the new ICV and checked the throttle cable movement. I have also noticed:
The car sometimes feels like its holding back under acceleration then suddenly picks up.
While driving at constant speed I can feel the car constantly pulling back and then 'letting go' then pulling back and then 'letting go' etc..
When I fully release the accelerator, the engine feels lumpy for the first few seconds but doesn't happen if I release the accelerator slowly. I have given as much information as I can, so I hope someone could steer me into the right direction on this... I know there is a switch at the top of the clutch pedal. I tested this with a multi meter. It seems to connect and dis-connect ok. I have removed this from its mountings until I can get this sorted. Thanks!
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Fiesta Zetec hot idle
19 June 2009, 9:13 PM
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carlos
Joined 2 Jun 2007
142 posts
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why didyou replace throttle pos sensor is it because of known fault? ie idle flare up when depressing clutch also along shot but dissconnect battery for 5 mins reconnect allow fast idle 2000rpm 2 min then drive car 15 mins this resets the mems system in the ecu and it relearns its values if this dont fix it get the ecu read for faults as it could be a low input value from air mass meter and you cannot tell by looking unfortunatly regards carlos
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Fiesta Zetec hot idle
20 June 2009, 9:16 AM
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topmansparkie
Joined 1 Jun 2009
3 posts
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Hi CarlosI replaced the TPS (and the Idle control valve) because the revs were up and down all over the place irrespective of whether the engine was hot or cold. I also had a lot of idle hang when lifting off the accelerator.
I changed the TPS first, then the ICV. I tried disconecting the battery several months ago after changing the TPS. But have not done it since changing the ICV and the coolant temp sensor. I will try disconnecting the battery again. I did have the ECU read for faults a couple of weeks ago. There was a fault from the Speed sensor. The garage told me they 'suspected' this may be faulty. At the moment I am not sure about replacing this on a 'suspicion'.
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Fiesta Zetec hot idle
31 August 2009, 10:21 AM
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tinny
Joined 14 Sep 2006
36 posts
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Hi, I wonder did you find a solution to your problem as my sons Ford Cougar is doing the same thing any any help would be much appreciatedthanks
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Fiesta Zetec hot idle
31 August 2009, 6:32 PM
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topmansparkie
Joined 1 Jun 2009
3 posts
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To be honest, I haven't found a solution. As it stands, my Fiesta is runing with the clutch pedal switch disconnected. The idle speed sits at 1000rpm, but I can live with that.The diagnostic check I had done months ago came up with a faulty gearbox speed sensor.
But thinking about it, I have work this out: When I bought the car, the speedo cable had broken away from the speed sensor. I left it like that for a few weeks after which I replaced the cable. I had a lot of trouble getting the rusted end of the cable out of the sensor, but after a fight, I managed it. After the cable replacement, is when I started having trouble. This would explain the speed sensor fault on the diagnostic.
I would replace the speed sensor, but as the car is fine as it is, I can't justify the £140+ part from main dealer. A second hand part maybe be ropey as I don't know if I'll get a working one. I don't know if this will help you or not!
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Fiesta Zetec hot idle
1 September 2009, 9:37 AM
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tinny
Joined 14 Sep 2006
36 posts
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Hi thanks for your speedy reply.. i agree that if the car is running fine then why spend any more money on it.. We discovered that the problem with my sons cougar only happens when the air con is switched on therefor like yourself we can live without the air con for the moment.thanks again
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Fiesta Zetec hot idle
1 September 2009, 3:04 PM
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bonscottkicksass
Joined 7 Apr 2006
19 posts
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I had probs with a 96 1.25 zetec fiesta wher it would hold the revs when you came off the accelerator pedal and also tickover sat about about 1500rpm.
Four pipes come together just between head and bulkhead and they were drawing in air.
Might be worth a look.
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Fiesta Zetec hot idle
2 September 2009, 1:55 PM
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tinny
Joined 14 Sep 2006
36 posts
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Hi thanks for that i will have a look just incase
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