Technical Engine stutters at and above 2000 rpm

[Shaggy1966]

Hi Everyone ! (My 1st thread )

I have a 2008 Ducato 3.0lt comfortmatic motorhome that I am at my wits end with as I’ve had this problem for over 5yrs now and after numerous diagnostics, new clutch, new egr, new throttle body and countless hrs of stress I thought I would see if anyone can help me ?

what happens is - when driving at 2000rpm and above the engine stutters for a second or two , this is not when accelerating hard but when cruising especially around 50mph and above. This happens in 5th and 6th gears mainly not usually under 2000rpm.

I have looked thru previous comfortmatic problems and have not yet come across this !

please can anyone give me advice to rectify this problem for good ?
many thanks

 

[bugsymike]

Total guess, but throttle pedal or associated wiring and connectors behind dash board?
I am thinking along the lines of a "duff spot" on the TP when trying to hold a fixed position.

 

[Shaggy1966]

Hi Bugsymike
Thanks for your thoughts !
Wouldn’t TP fault show up on diagnostics ?as it’s been on fault reader numerous times but never shown a fault !
But I can see your train of thought as it does seem to do it when the TP is held in the same position.

 

[Shaggy1966]

Also when I first noticed it
it was just a little blip but has progressively got worse over the years

 

[bugsymike]

I know on some diagnostics you can gradually depress the accelerator and get a progressive reading on your diagnostic screen.
I am not sure if the analogy is correct but I was thinking back in the old days as the fuel sender in the petrol tank moved it across a series of windings the resistance would change in the same way as a potentiometer works and if one part was worn or dirty the gauge could drop until the fuel level changed and the float sender moved to a good spot and became accurate again.
I know this is in simplistic terms, but if you moved the accelerator pedal a fraction up or down would the issue go away, as a test?
Perhaps someone else on the Forum can comment?
Do you have cruise control and if so does it do it then?

 

[Shaggy1966]

Hi !
Thank you for your reply. I understand what your saying but I’m assuming it’s fly by wire accelerator and I recently had a problem on our 500 accelerator pedal which brought a code up ! Would this do the same? It does have cruise control and I can’t say I have noticed it when it’s on ! Although it does like to change much more frequently !

 

[bugsymike]

Hi !
Thank you for your reply. I understand what your saying but I’m assuming it’s fly by wire accelerator and I recently had a problem on our 500 accelerator pedal which brought a code up ! Would this do the same? It does have cruise control and I can’t say I have noticed it when it’s on ! Although it does like to change much more frequently !

I am thinking it is because it is "fly by wire" that whatever changes the voltage as you press the pedal could be faulty in the way I described, by having a dead spot.
I am guessing that the cruise control only needs the throttle pedal when you manual change speed to disable the cruise control, same as if you touch the brake pedal.

 

[jackwhoo]

Diagnostic systems are not infallible .
Only after talking to the driver and gaining as much information regarding the issue/s can the fault finding start, part of which is intergatating the on-board ecu/s , then possibly reading live data from ecu/s. All the info should then be considered as a whole.
Lots of workshops don't allow enough time for a proper diagnostic procedure.
Lots of owners don't want to pay for a proper diagnostic procedure.

 

[jackwhoo]

How many miles has vehicle covered?
When fuel filter last replaced? - which brand used?
Same for air filter?

 

[Shaggy1966]

Vehicle has covered 55k , the fuel filter was replaced at fiat (about 20k ago) so I’m assuming it’s a genuine part and the air filter is a crossland I think !
Should these parts be replaced again ?

 

[Shaggy1966]

Where would I get diagnostics like that ? I have had it at Iveco/ fiat who say there is no software updates for this year as it uses old software?

 

[jackwhoo]

Noooooooo crosland filters dreadful.
Yes replace air filter with a good brand.
How many years was 20,000 miles ago? Did problem change when filter last replaced?
When oil and oil filter last replaced.

 

[Shaggy1966]

Oil / filter change done 6.5k ago and just checked it was Bosch air filter same time.

Well looking at the average mileage per yr it was probably 4 to 5 years ago for diesel filter

 

[Shaggy1966]

I think I had the fuel filter changed because I had this problem so I guess it didn’t make any difference

 

[Shaggy1966]

I think I had the fuel filter changed because I had this problem so I guess it didn’t make any difference

 

[Shaggy1966]

Thanks bugsymike for your thoughts atm it’s my only route to explore