New member my mate smithton told me join stoked on threads though !! My Mk 2 1.2 punto will drive fine from cold even if i put my foot down and will drive for hours until i stop and leave it for 15 to 40 mins and then it will start and then die or just turn over at normal pace and not fire. But if i leave it about 45mins to an hour it will start fine again and drive like new !! Can any1 help please its driving me crazy I havent got time to wait around for hours for it to cool down :bang: Cheers

Usually an RPM (crank pulley) sensor fault. When the engine is switched off after a drive the heat soaks into the sensor and causes internal issues which prevent it reading correctly when trying a warm-start. When it cools down, the sensor starts operating normally again.

A 10 min job to replace (only a 10mm bolt to remove the sensor).

Ill give it a go I did read about a similar problem and they said that was what fixed it but my mate also recons the trottle body needs a good clean ! Cheers

If any1 else has any ideas feel free to leave them

martin14 said:

Ill give it a go I did read about a similar problem and they said that was what fixed it but my mate also recons the trottle body needs a good clean ! Cheers

If any1 else has any ideas feel free to leave them

Click to expand...

it will be the crank sensor

it's all to do with rpm at idle the car runs 750 rpm so the sensor when warm must only just be making a strong enoughth signal

were as when cranked the engine only turns 400 or so rpm witch when sensor is hot high resistance in windings is not enough the reason the sensors eventually do this even thou the windings have not broken is because magnets lose there magnetism if heated and cooled loads of times



but there's no reason why you shouldnt clean throttle body too they are prone to getting very dirty from oil breather if the pipe is not kept clear

Cheers i took the crank shaft sensor off to have a look and i think its the one i had off the previous engine (which had over heat 2 or 3 time due to the radiator and then blew up) because the wire was perished and brittle and had a tear where it joined the sensor so didnt have strong enough signal ! Ive tapped it up for now because i cant get another until tomorrow afternoon and ive got to drive from bridgwater to st austell !

probably how he drives