Technical Engine Idle revving up & down

[austenw90]

Hi

I just wondered if anyone could give any advice on the following.

On a number of ocassions now I have stopped at lights / junctions etc and the car begins to rev up and down (by around 2 to 3 hundred revs). When the revs drop the car shudders as if it is going to cut out but then revs back up again. It does it continuosly until I start driving again.

No lights or messages are coming up on the dash. The car is a 2.0 multijet has done 25k miles and isn't due a service for another 8,000 miles. Although I did have an oil and filter change at 23,500 miles to keep it running smoothly.

I've booked in the dealer (but not until 18th Dec) as it is still covered under an extended warranty that Fiat provided when I bought it in March this year. The car has just gone over 3 years old just 2 weeks ago.

Any advice would be appreciated.

 

[cardinalbiggles]

Hi

I just wondered if anyone could give any advice on the following.

On a number of ocassions now I have stopped at lights / junctions etc and the car begins to rev up and down (by around 2 to 3 hundred revs). When the revs drop the car shudders as if it is going to cut out but then revs back up again. It does it continuosly until I start driving again.

No lights or messages are coming up on the dash. The car is a 2.0 multijet has done 25k miles and isn't due a service for another 8,000 miles. Although I did have an oil and filter change at 23,500 miles to keep it running smoothly.

I've booked in the dealer (but not until 18th Dec) as it is still covered under an extended warranty that Fiat provided when I bought it in March this year. The car has just gone over 3 years old just 2 weeks ago.

Any advice would be appreciated.

Mine has done that 2 times now in the past month, its a 165 as well.

 

[austenw90]

Mine has done that 2 times now in the past month, its a 165 as well.

Does yours also sound like the cooling fan may have kicked on? It definetly isn't right that's for sure. Have you looked into it at all?

 

[whisky79]

Signifies a DPF regen on mine. Usually after a few miles of decent running with the engine up to temp. It either stops of it's own accord while driving or I wait for it to stop after parking up before switching off. Doesn't usually happen again for a week/150 miles so I know it's finished the process & points to it being the regen.

 

[cardinalbiggles]

Signifies a DPF regen on mine. Usually after a few miles of decent running with the engine up to temp. It either stops of it's own accord while driving or I wait for it to stop after parking up before switching off. Doesn't usually happen again for a week/150 miles so I know it's finished the process & points to it being the regen.

Next time it happens on mine I am going to to take a note of the mileage and see if that corresponds to the regen data from the cars computer.

 

[Most Easterly Pandas]

Signifies a DPF regen on mine. Usually after a few miles of decent running with the engine up to temp. It either stops of it's own accord while driving or I wait for it to stop after parking up before switching off. Doesn't usually happen again for a week/150 miles so I know it's finished the process & points to it being the regen.

What engines in yours

 

[whisky79]

Sorry, it's a 165 also. Plenty of trouble with the whole regen issue earlier this year but seems to be sorted now thankfully. Part of the solution for me was to leave the engine running if the above symptoms were occurring when I stopped anywhere.

 

[Most Easterly Pandas]

Sorry, it's a 165 also. Plenty of trouble with the whole regen issue earlier this year but seems to be sorted now thankfully. Part of the solution for me was to leave the engine running if the above symptoms were occurring when I stopped anywhere.

Ah right. Not sure if you've a similar DPF setup to my 120 with the 5th injector, although sound like your DPF system might be one of the nastier 'over fuel the engine to regen' types.

 

[cardinalbiggles]

Ah right. Not sure if you've a similar DPF setup to my 120 with the 5th injector, although sound like your DPF system might be one of the nastier 'over fuel the engine to regen' types.

Why is that nastier? All Fiat DPF regens are done by overfueling.

 

[Most Easterly Pandas]

Why is that nastier? All Fiat DPF regens are done by overfueling.

Because it increaes the oil level. Not all are done by over fuelling, the 1.6 engine has a 5th injector in the exhaust just before the DPF = no over fueling

 

[Big Black Stilo]

ive heard of oil level issues on BMW engines due to DPF regen.

who thought that this was a good idea?

 

[Most Easterly Pandas]

who thought that this was a good idea?

No one, bit its only an issue if the car isn't regularly service as advised, or if the system goes wrong.

 

[Big Black Stilo]

and doesnt the diesel thin out the oil?

 

[Most Easterly Pandas]

and doesnt the diesel thin out the oil?

I believe so, but use of certain specified oils should prevent any ill effects if the oil is changed as required.