Technical Euro 4 1.3 multijet intermittent loss of power and intermittent rough idle.

[CarlosT]

Hi all, I have a problem with my 2009 fiat 500 1.3 multijet that I hope someone can help with.
The car will start fine and goes well for a few miles then it loses power and runs rough. At times it also emits huge clouds of grey smoke.
When idling it will be smooth for a bit then rough for a bit and so on, almost cyclical.

Oil and filters have been changed and recorded in the ecu.

I have replaced the injectors with known good used ones and coded them with mes.
I have also replaced the map sensor and the turbo cartridge.

The turbo actuator is working fine if I use a mitivac on it and you can hear the turbo when you drive.

There are no error messages on the dash and no errors recorded in mes.

When it runs rough the fuel consumption figures on mes go through the roof and the correction figures go all over the place on the injectors.

Turbo boost actual is a bit higher than desired boost but not much.
Fuel pressure readings are fairly consistent with desired pressure.

Seriously doing my nut in and starting to look for a box of matches so any advice would be much appreciated.

 

[steveras57]

Id be suspicious that the high pressure fuel pump might be failing!any sign or smell, of leaking fuel under the bonnet?!

 

[CarlosT]

Id be suspicious that the high pressure fuel pump might be failing!any sign or smell, of leaking fuel under the bonnet?!

Not any leaks. I had wondered if it was sucking in air but then I drove it with mes plugged in and the consumption figures rise when it runs rough.

The crazy bit is that it will be totally awful then if you back off on the throttle and ease it back down the car will generally pick back up for a bit.

 

[steveras57]

If the fuel pump or injectors are failing its quite possible for it to over- fuel which could cause the symptoms you describe!

 

[bugsymike]

Any chance it is trying to do a Regen of the DPF?
Will your MES give that information?
Do you generally only do short journeys ?
Also check your engine oil is not becoming diluted with fuel if it is trying to Regen.
If so maybe try some DPF additive in the fuel and some longer trips with slightly higher engine revs, say nearer to 3000rpm than 2000rpm.

 

[jackwhoo]

Hi,
You could try unplugging the the MAF sensor and seeing if any change to symptoms.
It will trigger mil and give fault code but I see you have MES so you can clear them.

Best wishes
Jack

 

[CarlosT]

Any chance it is trying to do a Regen of the DPF?
Will your MES give that information?
Do you generally only do short journeys ?
Also check your engine oil is not becoming diluted with fuel if it is trying to Regen.
If so maybe try some DPF additive in the fuel and some longer trips with slightly higher engine revs, say nearer to 3000rpm than 2000rpm.

Thanks for your time bugsymike.
Yes mes will tell me if it's trying to regen and also the car's regen history.
I live in a county village so every trip is 10+ miles and mostly 60mph.
Dpf filter is showing 21% clogging so not really associated with that side of things.
I also have gone around to the tailpipe and put my hand over it at idle, definitely not a problem there.

I am starting to wonder if the egr valve might be causing the problem but in reality, no idea if it would cause these symptoms. Since it's almost impossible to get to, maybe it is the culprit

 

[CarlosT]

Hi,
You could try unplugging the the MAF sensor and seeing if any change to symptoms.
It will trigger mil and give fault code but I see you have MES so you can clear them.

Best wishes
Jack

I will give it a go tomorrow arvo. Thanks

 

[bugsymike]

"I live in a county village so every trip is 10+ miles and mostly 60mph." I assume not in the Summer with all the tourists around St Ives.

 

[CarlosT]

"I live in a county village so every trip is 10+ miles and mostly 60mph." I assume not in the Summer with all the tourists around St Ives.

Ah, wrong St Ives although I wouldn't mind a place by the sea.

 

[bugsymike]

Demonstrating my ignorance , roughly where are you?

 

[CarlosT]

Demonstrating my ignorance , roughly where are you?

I have moved to a village near Grantham but I was until recently at St Ives Cambridgeshire. That's just 20 minutes north of Cambridge. Still a fairly quiet place but not so quiet as here.