2.0 jtdm slight stutter - Alfa Romeo Forum
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2.0 jtdm slight stutter

I’ve had a slight stutter for a few months. The problem only occurs when the engine is getting up to temperature and when on a light but constant throttle. It’s kind of like the engine is holding back and releasing and holding back again in quick succession but not like a misfire. Typically this will be third gear around 25mph. If I open the throttle up and accelerate harder the problem disappears and there’s no problem when all up to temperature. The car was recently serviced with new filters including fuel filter but it’s made no difference. No error codes either. The car was remapped by a previous owner and I do find it lacking low down when pulling away but I think that’s a seperate issue. What do you reckon the likely culprit is?
Thanks. Adam
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I think there’s loads of info about this common ‘characteristic ‘ on here. Happens at about 1750 rpms when cold, EGR I believe. My 2.0 is totally standard with the same behaviour. Was thinking of a remap and EGR delete myself as I have a recent clutch and flywheel but haven’t got around to it yet.
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Don't think its egr….I blocked mine off to test.....no difference. Mine only does it at certain temps during warm up.....and sometimes not at all given enough throttle. I run a restrictor plate in the egr now (1 x 8mm hole)….also no difference.
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Originally Posted by Twedds View Post
I think there’s loads of info about this common ‘characteristic ‘ on here. Happens at about 1750 rpms when cold, EGR I believe. My 2.0 is totally standard with the same behaviour. Was thinking of a remap and EGR delete myself as I have a recent clutch and flywheel but haven’t got around to it yet.
I don't think you will be able to delete the EGR unless the fault is rectified first. Ive had the EGR mapped out at Autolusso during which time they ran a diagnostic to make sure all was in order prior to the delete. Ned did explain why at the time but I'm struggling to remember why its so important to have a fully functioning EGR before its deleted
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I don't think you will be able to delete the EGR unless the fault is rectified first. Ive had the EGR mapped out at Autolusso during which time they ran a diagnostic to make sure all was in order prior to the delete. Ned did explain why at the time but I'm struggling to remember why its so important to have a fully functioning EGR before its deleted
Thanks for the info. It’s getting an MOT next week so I’ll ask a few questions. I only notice the stuttering on one particular drive I have to make when I’m restricted to 20/30 mph for the first 3 miles of the journey.
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I have exactly the same issue, completely standard 2.0 JTDM, and the same slight 'fluctuations' at low revs when cold etc.

Mine has 100k on the clock, so I'm starting to think about what I might do when it gets to nearing time for a clutch change.

Twedds - how many miles did yours manage before you needed the clutch?
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No point doing the clutch without the DMF on these.....but Im guessing you already know that!!
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No point doing the clutch without the DMF on these.....but Im guessing you already know that!!
Yes, absolutely - for those who have done it, what was the total cost and at how many miles...?

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Originally Posted by rancidswan View Post
I have exactly the same issue, completely standard 2.0 JTDM, and the same slight 'fluctuations' at low revs when cold etc.

Mine has 100k on the clock, so I'm starting to think about what I might do when it gets to nearing time for a clutch change.

Twedds - how many miles did yours manage before you needed the clutch?
Rancidswan,
Bought this 159 2 years ago with 72k on it from a garage in the Manchester area. First thing I did was put a cam belt and water pump on it at Quick Sale Ferryhill (see your’e in the Durham area), who I have used for all my Alfa’s in the past. On checking the vehicle out they informed me of the DMF being knackered and so it was done under warranty. I paid for the clutch kit only as it still had a lot of meat on it but as the labour was being paid for already!
DMF and clutch change therefore only cost me about £250, probably nearly a grand cheaper due to the garage warranty!

Last edited by Twedds; 01-09-18 at 11:49.
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1st and probably the most obvious and cheapest issue:

Try cleaning the boost control valve on the front strike plate... Open the circular end cap with a small flat blade screwdriver. Remove the foam filter and give it a wash. Allow it to dry and use carb cleaner and a tooth brush to get rid of the grime inside the valve body where the filter sits. Remove the pipes and label them, spray carb cleaner down them.
Refit it all together and then try the car.

2. Egr as already mentioned. Blank it for a few quid to see if it eliminates the hesitation.

3. Try another members fuel rail tuning box at a local Alfa meeting. I'm sure someone would let you try it, I would!
It takes 5 mins to fit then take it for a drive, if the issue disappears, then you have a lazy high pressure pump hesitating on light throttle... Save a fortune on a replacement as there is obviously nothing wrong with it on the higher demands of delivery. Get your own tuning box and appreciate the extra benefits of better power and torque instead.
4.. be happy you've saved a fortune!
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I've tried the first two...and many others as said...made no difference. In my experience more of the 2.0s do it than don't. As for the third one...well I've got a box fitted now....just going to drive is a few days before I report back...but so far so good. I'm still convinced it's a software issues...more bad code....let's face it, there are not the best at it! Two folks I know with remaps have lost the stumble completely.
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My car has a remap (supposedly for economy) and still has the issue. That said it doesn’t feel the greatest remap so I may try one from an Alfa specialist.
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My car has a remap (supposedly for economy) and still has the issue. That said it doesn’t feel the greatest remap so I may try one from an Alfa specialist.
Don't get a remap from anyone who does not set it up on a rolling road and tailor the map to you individual car...waste of time otherwise....might is well just get a box!!

Done about 100 miles with the box in the last 24 hours.....stumble seems to have gone but not counting my chickens yet as I've thought I've cured it before....only to have it reappear! Its so much nicer to drive though....no gutlessness off idle, much more overtaking punch. Feels how ALFA should have built it. Got to control myself though....its either going to cost me a lot more in fuel....or my licence!!!
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Originally Posted by adf83 View Post
My car has a remap (supposedly for economy) and still has the issue. That said it doesn’t feel the greatest remap so I may try one from an Alfa specialist.
Don't get a remap from anyone who does not set it up on a rolling road and tailor the map to you individual car...waste of time otherwise....might is well just get a box!!

Done about 100 miles with the box in the last 24 hours.....stumble seems to have gone but not counting my chickens yet as I've thought I've cured it before....only to have it reappear! Its so much nicer to drive though....no gutlessness off idle, much more overtaking punch. Feels how ALFA should have built it. Got to control myself though....its either going to cost me a lot more in fuel....or my licence!!!
Lol. Almost scary how rapid they get along the road without you realising just how quickly it gets to triple figures isn't it?

If it does happen to stutter again on light throttle, it could be the the throttle position sensor on the pedal assembly playing up. Its susceptible to partial signal loss when worn. Most of the time everyone tends to drive on light throttle in town driving so that position on the potentiometer gets the most constant wear and tear. Give it a good clean down with electrical contact cleaner and make sure the plug terminals are nice and bright first... It could be all it needs mate. Seen it loads of times on cf3 petrol 156's and most owners tend to change the throttle body motor to no avail not actually thinking it could be a fault at the opposite end!
Hope you get it sorted though.
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Does the throttle potentiometer come apart to clean?....not looked that close to be honest. On other cars I've had they were sealed so could not be cleaned.
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Originally Posted by alfaitalia View Post
Don't get a remap from anyone who does not set it up on a rolling road and tailor the map to you individual car...waste of time otherwise....might is well just get a box!!

Done about 100 miles with the box in the last 24 hours.....stumble seems to have gone but not counting my chickens yet as I've thought I've cured it before....only to have it reappear! Its so much nicer to drive though....no gutlessness off idle, much more overtaking punch. Feels how ALFA should have built it. Got to control myself though....its either going to cost me a lot more in fuel....or my licence!!!
What box are you talking about and how does it fix the stumble?
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A diesel tuning box.....Makes the car around 201 horses rather than the stock 170 and transforms the drive. Mine is a Probitz on butthere are loads on the market....most pretty much the same. However........the stumble returned. Turned out to be the crankshaft wheel thats drives the surpentine belt. New one on order.
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A diesel tuning box.....Makes the car around 201 horses rather than the stock 170 and transforms the drive. Mine is a Probitz on butthere are loads on the market....most pretty much the same. However........the stumble returned. Turned out to be the crankshaft wheel thats drives the surpentine belt. New one on order.
How did you find out the crankshft wheel has gone. I would throw this in the dealers if I could be sure they were repairing the right thing, but it sounds like it could be quite a few things. How do you fit the box?
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I borrowed a new one from a friend. Fitted it to mine...no off idle judder. To be honest, at first glance, mine looks ok.....but the rubber section is very hard and had lots of fine cracks where it's old...possibly original. I think the fact that the rubber is too hard has removed its ability to camp out vibrations.
The tuning box simply plugs in between the fuel rail pressure sensor and the rail itself. Search here and online...many threads about tuning boxes....both for and against...but at the end of the day short of increasing boost (not great for engine life although you to get a faster turbo spool up due to the box) the only way to get more power from a diesel is to inject more fuel ...and that's what it does. Diesels don't have a throttle valve so air metering does not enter the equation....well at least until the point where you are injecting so much fuel that there is not enough oxygen to burn it....hello black smoke!
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