Technical Cold engine rpm goes up and down

[sparkymk2b]

When is my 1.2 8v engine cold is "nervous". Rpm goes up and down. I cleaned idle control valve in last year, change all spark plugs, cable and both coil about 7000km ago.

This happened yesterday first time when car sitting about 3 days on cold weather. When I start car is everything ok and then I suddenly stop and turn off engine(engine have 50 degrees). Then I start engine second time and now he goes "nervous"(shaking and rpm goes up and down).

FES and MES say no errors in my car:bang: Is lamba, broken coil or something else

 

[Ziggy122]

When is my 1.2 8v engine cold is "nervous". Rpm goes up and down. I cleaned idle control valve in last year, change all spark plugs, cable and both coil about 7000km ago.

This happened yesterday first time when car sitting about 3 days on cold weather. When I start car is everything ok and then I suddenly stop and turn off engine(engine have 50 degrees). Then I start engine second time and now he goes "nervous"(shaking and rpm goes up and down).

FES and MES say no errors in my car:bang: Is lamba, broken coil or something else

Its like a shudder - but the rev's drop abit
I've put it down to the alternator kickup up hard to charge - engine bogs - and recuperates as the alternator demand is met and it repeats

Ensure the alternator belt isn't slipping / Ensure sufficient tension is been applied

Ziggy

 

[sparkymk2b]

Alternator belt is new changed about 3 weeks ago Yeah battery is sitting in real cold weather 3 days and probably has been weak but if battery weak car should increase rpm not jumping up and down is this true?

 

[sparkymk2b]

I drive my Punto whole week and works really fine Only god now what happened last Sunday

 

[judderbar]

This happened yesterday first time when car sitting about 3 days on cold weather. When I start car is everything ok and then I suddenly stop and turn off engine(engine have 50 degrees). Then I start engine second time and now he goes "nervous"(shaking and rpm goes up and down).

I have the 16V later car but the arrangement of the temperature sensor and external pipe back to the pump might be similar on your car.

One time I drained my coolant while in a heated garage and pushed the car out into the cold weather and then refilled with the 'warm' coolant and started the car and the engine went crazy for a while. I found the experience to be very unnerving.

It could be you recreated a similar kind of mixing of engine temperatures that the computerised car cannot manage very well.

 

[sparkymk2b]

Thanks for this. Yes interesting thing is my engine temperature sensor which say engine have 50 degress and outside temperature is 22 degress.. the truth is outside temperature is 10 degress and engine have about 35 degress:bang: