Punto won't start when engine is hot

[stormbringer001]

ANY help would be appreciated here. I've a Fiat Punto Mk2. Occasionally it cuts out when idling in traffic. Engine will not restart until it has cooled down - around 20 minutes. The engine cranks and cranks but will not fire up.
I've changed the temperature sensor ( but temperature gauge still 'dips' now and then) and fitted new plug leads as there was a slight misfire at idle. Local garage shows no error codes. Apart from this problem it runs perfectly - no sign of hesitation or anything, runs really smooth. Local garage is not much help as this problem is intermittent. I've researched a lot and can discount lambda sensor - map sensor etc as the symptoms don't match.
Any suggestions welcome!

 

[Vlad85]

Did you change spark plugs recently? If yes - then you got wrong ones.

 

[stormbringer001]

Plugs were changed on last service (6 months ago) - but I had this problem before then anyway, so I don't think it is that. But thanks for the suggestion.

 

[7797archer]

more than likely the crank sensor. sensor sounds like its going open circuit or got a very high resistance when hot.

 

[stormbringer001]

Thanks for that suggestion - crank sensor is now my main suspect. I'll get my shopping list ready lol ... crank sensor - ignition coils - map sensor - ecu - fuel pump etc ... one way to get a new fiat - the long war around!!
Thanks for the suggestions.

 

[Vlad85]

If you are lazy or have no time the best way is to get it to fiat service and get them to find what gives the trouble, and then buy the right part and install it your self. Or if you have a friend with Punto you can borrow parts and try to find broken one on yours, its easy to do with ecu/sensors/coils. Or spend some time on forums

 

[stormbringer001]

I've just ordered a new crank sensor online and a local garage will fit it for £15. I know it's an easy enough job but due to severe back problems I'm not very mobile!
Fingers crossed that this will cure the problem - will keep you posted as this may help anyone else with these problems .... quite a common one by the look of things.

 

[stormbringer001]

Well I fitted a new crank sensor! What I can't understand is why Haynes manual says you have to jack the engine remove engine mounts dismantle timing cover - the cable runs OUTSIDE of the belt cover in a grooved run.... so simple to replace!
I was amazed taking it out for a run... the mpg just went up and up and up. For months I've only been getting 29mpg now it's up to 42mpg and that was on a local run. Fingers crossed that the problem of cutting out is now solved!!
Thanks to all for help and suggestions.

 

[stormbringer001]

Well just to end this thread.... It's now been a week since the crank sensor was fitted and no more problems!! Thanks to all for suggestions and help