ford fiesta 1.1 cfi ( k reg 80k ) cold start problem.
car starts & runs for 5 to 10 secs and dies then refuses to start. only way to solve is a tow then runs perfectly. warm start no problem. car has been checked by local garage 3 times and computer faults rectified ie. new lamdba & mass air sensors fitted. garage now at a loss to solve. once running engine never misfires and never hesitates even when cold. someone must know the answer, but who?
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These models can suffer from overfuelling when cold as I think yours is.A modification which I've found to be effective is to wire in a 47KOhm resistor in parallel with the coolant temperature sensor.(This sensor is awkwardly located on the underside of the inlet manifold.but once you have accessed the wires it is easy to do).It has the effect of reducing the fuelling when cold and has very little effect when the engine is warmed up.Another way around the problem is an updated ECU for the engine management but really too expensive,in my view.
Incidentally your model uses a MAP sensor not a mass air sensor so I'm assuming its the MAP thats been renewed.
David Davies (Tune-Up Raglan)
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many thks for taking the time to reply, but I'm surprised you suggest 'over fueling' might be the problem when I & the garage suspect the opposite! The problem occurred again this morning but by holding in the starter for far too long, about 25 secs, the engine eventually fired. after a few secs it cleared its throat and ran prefectly !!! confused
with regard to the replaced sensor you are correct.
regards
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Congratulations to David Davies of Raglan Tune-Up for the reply to my cold start problem. Have fitted the resistor, cost 1 penny!, a week ago and car has started every morning since. The engine fires up differently, ie. turns over for 3/4 secs and starts and runs perfectly, whereas before it fired immediately but died soon after.
So many thanks, you have saved me time, worry & money. Your expertise is much appreciated. Kev the Rev.
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On the face of it a very elegant mod.
When the coolant is cold, a 47K resistor in parallel with this ECT sensor makes the ECU think the coolant is at 15 deg C, and gives less cold start enrichment than it would at say 0 deg C. When the coolant actually gets to 15 deg C, the ECU will think the coolant temp. is around 30 deg C. The difference diminishes as the coolant temp increases, such that at 80 deg C actual coolant temp, the ECU thinks its 83 deg C. Thus giving a bit more overheat protection as well.
IMHO Very elegant indeed.
I think the original calibrator should be quite embarrassed!
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