Technical juddering at 1.5K rpm JTD

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Technical juddering at 1.5K rpm JTD

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my car has developed a judder at 1500rpm. (its a 1.9 JTD 115).

Theres nothing that ive noticed while im driving but if im idleing in neutral and slowly rev up to 1.5K, only at this point does the engine judder. It just shakes much more noticabley and isnt as smooth. Once i increase the revs further it goes away and is as smooth as usual.

when i bought the car the overboost kept failing (and the turbo would drop out) because it was clogged up, it was cleaned out and never been a problem since.

I also recently, in the summer removed my throttle body and egr and thouroughly cleaned those. I also replaced the map sensor.

The oil was changed in october and the car was serviced less than a year ago.

The only engine mod is a cone filter.

Any suggestion to why this is occruing? My thoughts at the moment are that this is arround the rpm when the turbo has spooled up so im thinking either a problem is resurfacing with the over boost valve (still in its original possition) or posibley dirty injectors? like theres a stutter because the fuel requirements arnt being meant that are demanded by the sudden increase in air?

any thoughts would be much appreciated,

cheers

Stu
 
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my car has developed a judder at 1500rpm. (its a 1.9 JTD 115).

Theres nothing that ive noticed while im driving but if im idleing in neutral and slowly rev up to 1.5K, only at this point does the engine judder. It just shakes much more noticabley and isnt as smooth. Once i increase the revs further it goes away and is as smooth as usual.

You mentioned juddering at 1.5000 RMP, does it have a Kangaroo effect and do your revs accelerate up and down between a maximum peak of 2000 RMP? :confused:
 
is it possible that this can come from the exhaust (cat converter) because i have seen a similar thing to this and have looked at the exhaust whilst it is kept at this speed and you can kind of notice there is a bit of movement in the exhaust ?
 
could be from the dual mass flywheel. i have a judder between 1500-2000rpm, its more prominent on large throttle openings at 1500rpm. Do you also notice the clutch is fairly heavy as well. Mine doesn't affect the driving of the car but it will get progressively worse over time.
 
could be from the dual mass flywheel. i have a judder between 1500-2000rpm, its more prominent on large throttle openings at 1500rpm. Do you also notice the clutch is fairly heavy as well. Mine doesn't affect the driving of the car but it will get progressively worse over time.

I can see that were not referring to the same symptoms, mine is a kangarooing effect most definitely which has been widely covered on the Abarth and petrol versions of the Stilo in the FF :slayer:

So far from what i have read the kangarooing effect is not a subject specifically covered within the JTD`s, the petrol verison posts did however help me work around the potential parts and eliminate each one by one until I got my answer :yuck:
 
I had the same problem, a 2 years ago, along with annoying vibrations at idle, but everyone told me that "they all do that". Bought the vehicle just a few weeks ago, so I had absolutely no reference at this time.

Above 2K, the engine was performing beautifully, pulling strongly and neatly but... Fuel consumption was a bit deceiving compared to specifications or feedback of members from the French Stilo forum.

Finally, found out that 1 injector was faulty.
Simply disconnected each injector, one after one (don't forget to sw IGN off, reconnect, and then SW IGN ON between 2 attempts otherwise ENG computer will cut injection to the 4 cylinders)

When disconnecting 1 of the 4 injectors, I noticed little change in engine vibrations while with the 3 others, difference was quite noticable.

Around 1400 rpm, I could notice absolutely NO difference in engine harshness with injector connected or not.

Then I swapped the (potentially) guilty injector with it's neighbor... and the problem moved on the other cylinder. BINGO. !!

For the peace of mind, I performed a leak measurement (backflow from the injector) = The culprit was leaking badly, releasing twice the amount of fuel compared to the others.

Changed this injector for a brand new one (bargain on eBay, so no attempt to clean or repair it) and things greatly improved. Substitution of the engine mount under the battery definitely cured the reluctant remaining vibrations issues.

Now engine runs great and ... smooth, like it should. Hope it will help and there's nothing to loose as the checking (disconnecting, reconnecting) costs exactly 0£

best regards
Sébastien
 
Finally, found out that 1 injector was faulty.
Simply disconnected each injector, one after one (don't forget to sw IGN off, reconnect, and then SW IGN ON between 2 attempts otherwise ENG computer will cut injection to the 4 cylinders)

When disconnecting 1 of the 4 injectors, I noticed little change in engine vibrations while with the 3 others, difference was quite noticable.

Around 1400 rpm, I could notice absolutely NO difference in engine harshness with injector connected or not.

Then I swapped the (potentially) guilty injector with it's neighbor... and the problem moved on the other cylinder. BINGO. !!

For the peace of mind, I performed a leak measurement (backflow from the injector) = The culprit was leaking badly, releasing twice the amount of fuel compared to the others.

Changed this injector for a brand new one (bargain on eBay, so no attempt to clean or repair it) and things greatly improved. Substitution of the engine mount under the battery definitely cured the reluctant remaining vibrations issues.

Sébastien

Hi there

This may sound daft, common, usual, predictable, or even familiar but please find below a pic of my engine below and could somebody please confirm for me where the fuel injectors are?? And is it as simple as unplugging and swapping around fuel injectors to test for failures????

The last thing I want to do is to have a pipe and plug party leaving me with oil and fuel everywhere, if you get what i mean (y)
 

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The injectors are the four round devices which have the interconnected fuel-pipe running between them & with a electrical plug connection to each unit ... In the centre-line of your pic between the valve cover & the inlet manifold
 
The injectors are the four round devices which have the interconnected fuel-pipe running between them & with a electrical plug connection to each unit ... In the centre-line of your pic between the valve cover & the inlet manifold

Top man and thank you for your time (y)

Would you by any chance know the procedure to unplug and test the fuel injectors?
Via FiatECU scan I have had no warnings, errors or faulty readings on the injectors but as sprint750 above mentioned an easy procedure to test them manually I am eager to carry out the procedure (y)
 
Top man and thank you for your time (y)

Would you by any chance know the procedure to unplug and test the fuel injectors?
Via FiatECU scan I have had no warnings, errors or faulty readings on the injectors but as sprint750 above mentioned an easy procedure to test them manually I am eager to carry out the procedure (y)
The procedure is already detailed in Sprint's earlier post, namely :-

"Simply disconnected each injector, one after one (don't forget to sw IGN off, reconnect, and then SW IGN ON between 2 attempts otherwise ENG computer will cut injection to the 4 cylinders)

When disconnecting 1 of the 4 injectors, I noticed little change in engine vibrations while with the 3 others, difference was quite noticable.

Around 1400 rpm, I could notice absolutely NO difference in engine harshness with injector connected or not."


IF that test "suggests" a faulty injector, THEN you can try swapping injectors as per :-
"Then I swapped the (potentially) guilty injector with it's neighbour... and the problem moved on the other cylinder. BINGO. !!"
 
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