Technical Doblo 1.3 D Multijet - Stutter / 'flat spot' problem

[Monica F Hewitt]

Hi there, I was hoping some of you experts may be able to shed some light on a problem I have with my van.

Its an 08 1.3 Deisel Multijet Doblo. I find when over 2k and lift off the accelerator, then apply a small amount of throttle at around 1.6 - 1.8k there is a very brief judder or 'flat spot'. Its not something that stops the van working and have taken back the to main dealers who are pants, and of course couldn't find it. Its not something that you feel espcaially as a passenger but as its driver 6 days a week I find it very irritating. Its more noticable up hill and on flat but does it in all cercumstances.

Not sure if a problm with throttle electronics, injectors, earbox slack or what. Any ideas?

Fanx, MFH

 

[s130]

Only guessing but could be and EGR valve problem. EGR valves open anywhere between 1000 rpm and 3000 rpm, but then close.

They are supposed ( I think) to be closed on over-run. If the vlave is not closing properly on over-run the when you gently apply the throttle again, the ECU delivers less fuel than is required for normal combustion.

Most Fiat diesel engines measure the air intake PRIOR to the EGR feedback/inlet path. The ECU measures the cold air intake and then adds a correction factor for the extra EGR air input based on engine rpm and EGR duty cycle.

Coming off over-run the EGR additional air intake should be initially zero. The ECU then injects fuel levels in accordance with the MAF signal (mass air flow). Any additional EGR leakage due to a slightly stuck valve is not factored into the caclulations and the net result is a weaker fuel mixture.

In extreme cases of stuck / open EGR valves then there is a massive lack of power below about 3000 rpm.

 

[007licenced2thrill]

EGR would be the area to look at. you need your dealer to follow service news on elearn system. to correctly diagnosis fault.
Or remove EGR, seperate, clean and dry. and refit.
and fit the modified holed EGR plate to reduce the judder. Also detailed withn the same service news.

 

[T14086]

fit the modified holed EGR plate .

for 1.3jtd?

 

[007licenced2thrill]

Depending on the EGR fitted. four pin or two pin connection on the inlet side.

 

[T14086]

only seen them with 2, personally after getting access to EGR i'd be changing it insteard of cleaning.

 

[007licenced2thrill]

depends how rich you are. or desperate to get it on the road till replacement part arrives.

 

[Peccadillo]

Can`t it just be blanked off?

 

[T14086]

EGR is there for a reason.

 

[Peccadillo]

EGR is there for a reason.

Hardly time to turn over the egg timer - as expected.......

(was oilrag):devil:

 

[T14086]

I know (IP address) so had that service light put out yet:devil:

 

[Peccadillo]

T, I would really appreciate your knowledge on this thread (my final post sums it up)

It`s OK if you don`t have time.

All the best to you

https://www.fiatforum.com/punto/204058-1-9d-engine-oil-spray-advice-please.html?p=2202213

 

[T14086]

of course, remind me if I forget

 

[Peccadillo]

"apply a small amount of throttle at around 1.6 - 1.8k there is a very brief judder or 'flat spot'."

Monica,

I bet there`s nothing wrong with your car. I have a van with the 1.3 Multijet and it`s always been as you describe yours.

It`s a small capacity turbo diesel and as such depends on its turbo to produce significant power. If you drive it so that you never let engine revs drop below 2,000 revs there will be no problem.

I think you are describing the lack of power before the turbo boosts the power at just under 1,800 revs. There`s no point in trying to drive one of these engines lower than that.

All the best

 

[Peccadillo]

of course, remind me if I forget

Does that mean `go to your main dealer? (and give us your money):devil:

 

[ivantate]

Our panda has got progressively worse over the last few thousand miles with a noticeable lag compared to before. Will take the egr off and have a look and a clean. Not done it before so will see how it goes.

Still great economy but smokey at times when starting and seems to crank for about 3 turns before firing even when hot.

4 crossings of the alps with some foot down driving on the autostradas and over the passes has failed to clean the egr valve the easy way.