My Palio start fine once cold. As soon as the temperature rises slightly it starts jerking in gear and often cuts out taking a good half hour to start again. At times the revs are also very eratic and this is often after warming the car up. Sometimes the battery has to be disconnected for half an hour or so and then car only starts by taking a plug lead off and shorting it over the top of the engine.....

Welcome to the Forum!


About your question: what modelyear, and what engine...??

Its a Palio 2005 1.2 el

Did you have the ECU read already..??

Was read and decoded and the problem persists. Had new injectors and coil fitted too. Some say its the thermostat others say its the petrol sensors...

Diagnostics was run and also showed no problems. Another mechanic also told me it could be wrong spark plugs or crank shaft sensor fault.
Please Help me with sorting out this problem as this Palio is our only means of transport to convey kids to school etc.

Could be O2 sensor, it's worth trying.
Fiat says to fit a new one after 120.000km's after all...
Bad crankshaft sensor causes sudden engine cut out, I don't read about that in your first post..
It's also a good idea to have the inlet cleaned, specially the throttle flap, dirt build up there will cause idling problems as well.

Im not much of a mechanic apart from keeping old cars going so will slowly try find all that and go through one by one. I was also advised to take out thermostat to ensure free water flow when warm. Will maybe that also help in the meantime ?

I don't think that's a good idea, if it's working, leave it.
ECU depends on accurate engine temps, controlled by, among others, the thermostat.

Thanks. Will just leave everything for now until mate can come around with diagnostics machine. Until then will just use car in early morning when outside temp is still cold as car mostly go's fine then apart from few jerks and bumps.

How do I check if thermostat is working properly ???

Temp. gauche comes up within ~5-10 minutes, and stays somewhere in the middle..

Thats what I been used to in all my other cars but this Palio the gauge hardly moves off the cold when the car is running ok but as soon as Im in heavy traffic it moves to 1/4 and thats when the cutting out starts. If I can quickly get out of the traffic like onto a freeway, the temp drops back to the C mark and car runs fine but jerks quite badly when changing gear.

Replace it, it looks like it's bad.

Before it cuts out, does the exhaust smell like unburnt petrol?

Starting ok when cold, but then cutting out suggests temp sensor is not working. This causes it to continue to run rich, as a cold engine needs, but will flood a warm engine. This will not show a code, because whatever the ECU gets from the sensor it will assume is ok.

As it warms up, hold the top hose. It should suddenly get hot as the thermostat opens. If thermostat is stuck open, hose will warm gradually, if stuck shut, it wont get hot. Temp gauge showing low suggests open stat, or faulty temp sensor. With the diagnostic machine plugged in, watch the temp reading to see if it rises as expected.

Thanks for that info. Will do the hold hose test over weekend as out of town now. Also can only get hold of diagnostics machine sat or sun sometime. Will msg you at latest sun to let you know of any results.
Thanks again....

Thanks for that info. My mate coming around with the diagnostics machine and will try all that.

Mates diagnostic machine couldnt be used as had wrong connection so just went ahead and changed thermostat. Seems to run a bit better but once warm like at 1/4, the revs drop when idling and it cuts out. Most times starts immediately but at on occasion must wait a few mins before starting.....
What is now causing this problem ???

There should be some sort of idle control valve,in your car probably integrated in the throttle body, maybe it's dirty, or broken...??
Start with cleaning the inside of the throttle body and air flap with carburetor cleaner spray.
Don't know much about the later 1,2 versions, as they were never sold in my country, I'm afraid...

The car runs a bit better and starts easier when warm if I take the fuel cap off but will get some carb cleaner and try cleaning in hope that helps too. Trying everything as not much of a mechanic and its far too expensive to take vehicle to agents.

Thanks for all the assistance Im getting.