General bad starting when warm

[hopper450]

Hi,
I have an X reg fiat seicento that starts first and every time from cold. However when the car is warm it will cut out and stop if it is left on tick over or when you drop the revs at a road junction. It is then bad to start. Has any one any ideas. I personally think it may be something to do with the automatic choke. I have already changed the fuel filter and the spark plugs but it has not made any difference.

 

[fingers99]

There is no automatic choke, as such. Mixture is richened by the ECU mainly through engine coolanr sensor. (Blue sensor on inlet manifold.) Likely suspect.

I'm assuming SPI car. Can't compute Reg letters!

 

[dave]

welcome to the forum. you don't have a choke not even an automatic one, that is a carburettor thing you have injection, the amount of fuel is controled by the ecu, the ecu relies on temperature sensors to tell it how much fuel is needed to keep engine running, so may be an idea to check them

 

[hopper450]

Ok cheers for information. I will check tonight and let you know.

 

[g4jvf]

Seem to remember reading that crank sensors can fail when warm...
Might be worth considering..


Phil

 

[Eklipze3k]

I would also be checking the vacuum hoses as mine used to idle quite badly when warm until I found one of them split into the back of the throttle body.

 

[fingers99]

Seem to remember reading that crank sensors can fail when warm...
Might be worth considering..


Phil

Easy check for crank sensor failure. When conked, no spark, no fuel past the injector(s) (dry, not petrol smelly and wet, plugs). If not both it'll be something else.

 

[GeorgeDamper]

When you have eliminated Crank Sensor & Temp Sensor - have a look at the injector. Take off the air filter box and start the car. Look closely at the injector to see if it's leaking into the throttle body. I discovered this fault on my old Sei.

I've got a couple of spare injectors if you need one.

 

[hopper450]

ok cheers for all that information. I tried to plug in diagnostic tool just for curiosity but it would not connect for some reason. I have ordered a new temp sender and should be here tomorrow. I will update soon.