Technical The engine dies while driving!

[coconut]

I have a Fiat Stilo, gasoline, I bought it brand new from the Fiat dealer in 2004.

Last week it died on the highway while driving constant speed 110-120 km/h. The engine shutted off I noticed just because pressing the accelerator pedal had no response from the engine. So I turned to one side carefully because the car was slowing down by itself and I stopped the car on the verge of the road. I turned off the keys and then I restarted the car without noticing problems. The digital panel didn't show any warning/error messages. The gas tank was half-full (it wasn't near the refill reminder red mark, and it wasn't full neither)

This thing only happened to me one time a year ago. And now this is the second time it happens. Both times happened exactly the same situation, while driving on the highway constant speed 110-120 km/h fast, and so on.

The car works fine, never had problems. Now is in the repair shop to have a inspection ... Any help? Thanks in advance.

 

[Deckchair5]

A whole year between the fault occuring? That'll be easy to investigate then

For an engine to shut down with no faults displaying then I'd be thinking of something that turns off the ECU before it has chance to discover and register any faults so that would be ECU earth or supply going open circuit or body computer to ECU connections

Throttle body loss of comms would tend to put up a fault code

 

[stilotoby]

I had this problem too, yesterday evening at around 70, braked for a roundabout, changed down all the gears, went to pull away in 2nd doing 25mph and the engine just cut out mid roundabout! No warning lights etc, restarted fine.

My Stilo had the alternator changed a few months back as this was tracked to be the problem, only half an hour after the above mentioned happened, it happened again, only this time the engine cut out and a warning light came on saying alternator connection failed. I've checked everything cable wise and they are all fine! Could be a fun one to track....

 

[Deckchair5]

Alternator failure warning can put you off the scent here when the engine dies at running speed. The warning is quite correct but the reason is that when the engine is going above idle rpm and it just cuts out then car recognises rpm is good but there is no output from the alternator and flags the alternator warning but the reason is that something electrical has made the car ignition stop

So ECU and battery supply and earth would be on my hit list

Check your fault codes and look for other warnings when it dies again ( cos you know it will)

 

[vladof]

My father's car had a loose right undershied or how do you call it. When hitting the slightest of pot holes or when traveling at high speed and hitting an imperfection in the road the engine would die. No errors whatsoever, I would just see the RPM 0 and lurch the car to the nearest possible parking spot, restart engine, carry on.

It seemes the problem was that when hitting something the actual plastic shield would hit the car's distribution and stall it. I think it has a sensor or something because it dies instantaneously when something hits those belts. No errors, not even oil pressure for about 10 seconds or more.

Check that nothing is loose near the timing belts. It took me a while to figure out what the problem was, then changed the whole right undershield and presto, never stalled again.

 

[coconut]

I'm back! The car had an inspection. They replaced roller chain (needed a change), oil, air filter, and the left headlamp. For doing this replacement they told me they had to detach and attach some pieces (also the ECU?) because the left headlamp is placed on a weird place to get with a hand.
They can't find a reason about the car-die-while-driving problem.

I ride the car and is working fine as always. But I'm afraid it could die again suddenly while I'm driving ...

Thank you for the replies, your help is so much appreciated!

 

[stilotoby]

Hi mate. I've had a simliar problem with the missus car doing the same thing. I checked every single connection over the engine, cleaned every contact plug, changed loads of sensors and still didn't fix the problem. Got a new engine bay fuse box through just over a week ago and fitted it, problem solved. Seems the stilo engine bay fuse boxes are a lot more prone to failure than some others!

 

[Davren]

There's nothing in the engine bay fuse box to fail. It's just a plastic box with metal electrical connectors mounted in it. The only thing that causes problems with it is water ingress (especially if the large black battery cover is missing or a jet wash is used under the left front wheel). Problems caused by water ingress can easily be cured by drying and cleaning the connectors.