My stilo has developed yet another confusing electrical issue, wondered if anyone has any thoughts.

Started monday, had been driving for nearly an hour, was doing 70 on the motorway and the engine suddenly just cut out with dash flashing up "ASR fault", "Alternator fault", "Loose connection". Hit the hazards and rolled to a stop at the side of the road. Turned the engine over and it restarted fine. So tried heading off again, cut out again a few mins later. In short cut out 5 or 6 times in ten mins (I was near my mates house so persevered just to get there). Gives no warning and can always be restarted straight away.

So called AA (I'm not great with cars and didn't wanna risk the hour drive home), he checked the battery (only 3 or 4 month old) and alternator voltages, all good.

Checked for fault codes - nothing.

He was looking at it for a good 20 mins and it ran fine all that time just sat still and he was at a loss. He said he'd follow me home just in case, pulled away and had barely moved 100 foot and cuts out, Despite having been sat running for 20 mins fine. In short cut out about 8 or 9 times on the way home, and could restart it straight away every time (so had one hand on the ignition all the way home lol)

So tuesday I had it running in the drive for a good hour without problem, whilst tapping and jiggling wiring, fuses etc all round the battery top fusebox (I know that can be troublesome) and, having searched the forum, the seemingly infamous D4 connector. Could not get it to cut out. So just out of curiousity, took it for a drive, ten mins in and it cuts out, and again 5 mins after that.

And new today - the alternator warning light comes on when I turn on the ignition, but turns off immediately when starting the car. Yet took it for a good long run and wouldn't die

Much searching here hints at possible ECU issues, sensor issues, but could a dying alternator cause these issues do you think? I'm getting a good alternator voltage at the battery, but maybe if it's intermittently faulting I would? Or I could be barking up completely the wrong tree and the alternator light is just the Stilo's usual trick of alerting you to something completely different to the actual issue lol (I've dealt with alternator issues on other/older cars, but never on anything as electrically over sensitive as the Stilo so not sure what to expect)

open bonnet just to the right there is a multi connecter going to engine for injectors give this connector a wiggle and see if it has any effect on the running cutting out if it does cut it out and solder all wires up i bough a stilo been in and out dealers for years for cutting out all it was was bad connection in this connection a common thing with these cars

justy said:

open bonnet just to the right there is a multi connecter going to engine for injectors give this connector a wiggle and see if it has any effect on the running cutting out if it does cut it out and solder all wires up i bough a stilo been in and out dealers for years for cutting out all it was was bad connection in this connection a common thing with these cars

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I think I can safely say I've tried that as I've given every visible wire, cable and connector a good jiggle and tug

What Engine.

bri1232 said:

What Engine.

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The one in the car

Sorry, 1.6 petrol

I know this is a really dumb question but I'm doubting myself now - does the alternator warning light normally come on with a non faulty car when you turn the ignition on, before starting up? Or have I managed to completely fail to register it's existence in the years I've had it?

Have you had diagnostic codes read Engine ecu/Abs ecu.

bri1232 said:

Have you had diagnostic codes read Engine ecu/Abs ecu.

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Yeah, sorry, forgot to put it in the first post - AA guy checked for fault codes and there were none.

Just to ask again - the alternator warning light should go off with the ignition on (engine not running) shouldn't it?

Thanks. I thought it was a dumb question but in 15 years of driving I've never noticed it stays on!

Well I've bit the bullet and just put the car in to get checked out today, will update when they get back to me

Ok, update time:

Garage couldn't find a fault, or get it to cut out whilst they had it (sod's law)

No relevant fault codes, there was a "b100e speed indicator fault" and "b100c coolant temp gauge faulty" - I'm hoping neither of them are worrisome.

They suggested I take it away and run it for a few days after they cleared the fault codes, then take it back in. Which I suggested was kinda pointless given it's not throwing up fault codes when it happens. Their only other suggestion was to try replacing the crank sensor, but they weren't making any promises and the onus was entirely on me if I did. So for the sake of ruling it out (and impatience) I went along with it.

Needless to say, they replaced it and an hour's driving after picking it up and it cut out again.

So having read up on here about dry joints on the ECU connector pins being a potential cause, I went along every pin giving it a nudge to see if any were noticeably loose. Nothing obvious. Plugged connectors back in, started it up and the car cut out 4 times in less than 10 mins, which is more frequent than it ever has, and it has only cut out whilst stationary twice all week.

May or may not be coincidence but gonna try opening up the ecu to check for dry joints. Presuming I get it open, what's the best way of sealing back up? It seems to be held closed with some grey sealant of some sort.

Just use silicon sealent.

bri1232 said:

Just use silicon sealent.

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Thanks.

I'm not sure there aren't two different things going on now. Since the garage replaced the crankshaft sensor it's been cutting out whilst sat stationary, and without any warning messages being thrown up (which it always did with the original issue). Idle also seems very slighty lumpy since (though that could be my imagination/paranoia)

I resoldered the ECU socket pins, put it back on the car and driven for an hour without it cutting out like it originally was (not necessarily meaningful I know with an intermittent fault), though it has twice stalled while just sat idling on the drive.

Is there any set up involved with a crankshaft sensor that could affect idling or cause intermittent stalls? Or is that a complete red herring?

JDPower said:

Is there any set up involved with a crankshaft sensor that could affect idling or cause intermittent stalls? Or is that a complete red herring?

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Should be about 1mm gap between pulley and sensor.

bri1232 said:

Should be about 1mm gap between pulley and sensor.

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Could that cause it to stall at idle, or idle slightly lumpy? If so I can at least take it back to the garage armed with that info.

It went back to the garage, they said the sensor was not set up right and something had to be reprogrammed at teh local Fiat dealer (didn't check details, was just happy it was finally sorted, or so I thought).

Picked the car up, it was idling smooth again so had high hopes, drove for 15 mins all fine, got home, turned it off, restarted and within 20 seconds it stalled, no dash messages. Restarted and almost immediately it cut out throwing up all the usual dash warnings (ESR, Alternator, loose connection).

Am reaching the end of my tether with this effin car now, anyone want a cheap stilo?! :bang:

I'm afraid I have to welcome you to the Faulty 1.6 ECU club. I 've come to the conclusion that the fault is inevitable and it happens on the 1.6 model sooner or later.
Let's hope I 'll prove wrong...

Stormwatch said:

I'm afraid I have to welcome you to the Faulty 1.6 ECU club. I 've come to the conclusion that the fault is inevitable and it happens on the 1.6 model sooner or later.
Let's hope I 'll prove wrong...

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Looking increasingly that way, just wish there were a way to test an ECU is to blame without having to splash a few hundred quid on a replacement.

Well you can tap the ECU with the handle of a screwdriver while the engine is running. If the tapping makes the gremlins appear then it's the ECU for sure...

Stormwatch said:

Well you can tap the ECU with the handle of a screwdriver while the engine is running. If the tapping makes the gremlins appear then it's the ECU for sure...

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Yeah I did that, even opened it up and tapped the chips and across the circuit board generally and nothing, so I'm fairly confident it's not just a loose connection in there.