Tiny69 Posted March 24, 2023 Share Posted March 24, 2023 Dear Forum members. I have a 1.25 fiesta Zetec which won't idle AT ALL when cold. It doesn't even try. after 2 mins it tries to idle, then after 3 minutes or so it idles fine and smooth. No hunting at all. Once warm, if I rev it the revs come straight back down to 750 ish and does not dip lower even for a second. I have tried spraying WD40 and brake cleaner around all vacuum conections to see if engine note changes but engine note doesn't change. Any help would be greatly appreciated. Quote Link to comment Share on other sites More sharing options...
mburdett555 Posted March 24, 2023 Share Posted March 24, 2023 Any lights on the dash? Even just occasionally ? I had a 2012 cmax which had a similar issue, would die occasionally after a few minutes, very rough idling. Had the camshaft position censor replaced and fixed it, but could be spark plugs or or some other sensor. Quote Link to comment Share on other sites More sharing options...
Tiny69 Posted March 24, 2023 Author Share Posted March 24, 2023 Thank you for your comments. I'm sorry I forgot to mention there are NO lights on dash and NO codes on OBD reader. Also, If I drive it in those first 2-3 minutes when it won't idle it does run a bit rough up to 2000 revs. When warm, it drives fine and smooth Quote Link to comment Share on other sites More sharing options...
Tiny69 Posted March 24, 2023 Author Share Posted March 24, 2023 I'm an idiot. It's a Duratec 1.25. Not a Zetec. Quote Link to comment Share on other sites More sharing options...
Tiny69 Posted April 4, 2023 Author Share Posted April 4, 2023 I'm going to connect my scanner to it when it is stone cold to see if any sensors are reading way off then reading ok after 2 or 3 mins. I've had that before where a water temp sensor read -40 when cold and suddenly jumped to correct reading at about 20 degrees. Any other recommendations would be gratefully received. Quote Link to comment Share on other sites More sharing options...
Tiny69 Posted April 12, 2023 Author Share Posted April 12, 2023 I connected my Foxwell scanner today when it was cold and started the car. While the fuel system was running in open loop it won't idle at all. All temp sensors seem to give accurate data. As soon as fuel system switches to closed loop ( after about 3 mins) it idles as smooth as silk. Both O2 sensors are saying Lean but I can't find any fuel trim readings on my scanner that might tell me if I have an air leak. Quote Link to comment Share on other sites More sharing options...
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