Technical Engine cuts out / wont start

[Ekimmu]

I have a 53 plate Fiat Idea Eleganza which has lately developed a fault.

When I put the key in the ignition the dash lights up and the engine turns on and revs. After 5-10secs everything just dies, engines, lights on dash the works.

I had the AA out and they highlighted a coolant temp sensor issue, I took i to the garage who ran a diagnostic and found nothing wrong. The problem has since persisted. I took it to the fiat garage who ran a battery of tests and found nothing at all wrong.
They then reset everything to factory default as a precaution, the car has ran fine for a week again. Until now the problem has started again.

I am at a loss after 3 diagnostics and examinations have not found a fault. The correct petrol has been used, usually filled up before it gets too low a few times when the petrol light comes on.

I was wondering if anyone had any ideas about what the issue could potentially be?

Thanks

 

[portland_bill]

We need to determine either fuel, or electrical.
Fuel:
When the ignition is turned on, the fuel pump should prime, to ensure pressure is available, then it would stop. This prevents fire, if the engine is not turning, the pump stops. Then when cranking, the pump operates again. If after starting, the pump stops, the engine will die quickly as the fuel pressure drops. Fuel pump relay is suspect here. Ignition on and cranking by-pass the relay. Low oil pressure may also stop the relay.
A temp sensor would normally cause poor running, rather than a stop. If the engine thinks it is hotter than it is, fuelling will be weak until normal temp is reached. This can be overcome by juggling the throttle pedal. If the engine thinks it is cold, overfuelling will result, giving progressively rougher running as it warms up.

Electrical:
A bit more complicated, but possibly more likely. You say the dash lights disappear when the engine stops. Like you've turned the engine off? With a normal stall, the dash warning lights, battery and oil press, should all come on again.
If those lights are not on, we need to find why.
Check battery connections and earth connections from battery to gearbox and body.
Check ECU connectors for corrosion or broken terminals.
Ignition switch is a possibility. If the internal switch contacts are worn, or the whole rotating mechanism is worn, it may be literally switching the engine off. Are you using just the car key, or does it have a bunch of heavy danglies for house keys, other car, shed, work desk, etc? It is not uncommon for heavy stuff to pull the switch to break the contacts, so effectively switching the engine off. When it went to the garage, I bet you just gave them the one key.

Have a look at all that and report back.

 

[varesecrazy]

maybe unplug the fuel temp sensors for a while too,
reading / clearing the fault codes MAY help diagnose the issue too,

back to basics ;
how long have you had the car, how many miles..??
any recent work done= clutch / exhaust / battery.?

what engine size / fuel ??,
Charlie - Oxford