Technical Erratic Idle 2005 model 1200 8 valve

[fazerbill]

New to the forum Hi
I have an idle problem on my 1200 8 valve Punto 2005 model. The revs go up and down by about 250 on warm up and also restarting after 5 to 10 mins when hot.
The Fiat dealer replaced the throttle potentiometer but that didn't cure it. I spoke to one of their mechs and he said it was the stepper motor and was a common fault with Puntos. I told the service rep this and he said it was the same thing which I know is not the case, they are 2 different parts.
I took it back to the dealers today to try and solve this problem. I got a call this afternoon to say that the tickover was ok and they could not get it to pulse on idle. This is happening every time I start the car. I told them to keep the car untill they solve the problem.
Can anyone shine a light on this problem.

 

[Pars punto]

New to the forum Hi
I have an idle problem on my 1200 8 valve Punto 2005 model. The revs go up and down by about 250 on warm up and also restarting after 5 to 10 mins when hot.
The Fiat dealer replaced the throttle potentiometer but that didn't cure it. I spoke to one of their mechs and he said it was the stepper motor and was a common fault with Puntos. I told the service rep this and he said it was the same thing which I know is not the case, they are 2 different parts.
I took it back to the dealers today to try and solve this problem. I got a call this afternoon to say that the tickover was ok and they could not get it to pulse on idle. This is happening every time I start the car. I told them to keep the car untill they solve the problem.
Can anyone shine a light on this problem.

I know this post is old but i have exactly the same problem i swapped 4 clean throttle bodies, map sensor twice and they didnt have any effect on the erratic idle. When i drive the car its ok but when i let the car idle itself when its partly warm it comes back. When i drive the car for a while untill it reaches the operating temperature and turn the engine off leaving it for over half an hour then firing it up again the erratic idle comes back. One thing i noticed is when i pump the brake a few time while the engine is running stopps. To clarify a little bit more when this happens the revs constantly drop to 600rpm then after a second goes up to 800rpm (hunting?), when the revs drop it feels like the car is about to stall but of course it doesnt. Any ideas? thanks in advance
2004 mk2b active 1.2 8v

 

[Mar4ix]

Just guess.. might helps ... could be idle speed control ??

 

[Pars punto]

Just guess.. might helps ... could be idle speed control ??

well ive changed the throttle body 4 times, little chance of them all having a faulty idle control valve unless they are a faulty batch, i dont know. im thinking more in terms of ecu or coolant temperature sensor.

 

[Mar4ix]

well ive changed the throttle body 4 times, little chance of them all having a faulty idle control valve unless they are a faulty batch, i dont know. im thinking more in terms of ecu or coolant temperature sensor.

hmm ... then check coolant temperature sensor .. not expensive ... vacuum pipes need to check as well.... better change them ... make sure they good condition and properly attached. ... i dont know is manifold absolute presure sensor on your car ... would worth check that as well.
there is picture of program what i have, it suggest check -

hope it will helps

 

[Pars punto]

hmm ... then check coolant temperature sensor .. not expensive ... vacuum pipes need to check as well.... better change them ... make sure they good condition and properly attached. ... i dont know is manifold absolute presure sensor on your car ... would worth check that as well.
there is picture of program what i have, it suggest check -

hope it will helps

many thanks for your reply... i did the following and the fault was gone completely:
> replaced the coolant temperature sensor.
> upgraded the spark plugs to denso iridium power (got rid of mild misfires, jerking and smoothed out acceleration).
> cleaned all 3 earth points located below the battery compartment.
> i was satisfied the throttle body was clean but i took it off again and this time using a couple mini brushed toopicks and some carb cleaner i cleaned the inside of the icv tract.
> and finally reset the ecu using fiatecuscan which required me to carry out a phonic wheel learn.

thanks again