Technical Croma 2.4 JTD accelerate problem with shake reason

[CromaMkd]

Hello,

I own Croma 2.4 JTD 20V, product year: 2006 which I bought last year as second hand. Currently car has passed around 190.000 km.
I have a problem with my car, so that when I accelerate around 120-130 km/h car start to falter (shake) continuously so I have to lower gas pedal, and afterwards if I continue again to drive without stopping the car, this problem appears in lower speed continuously (e.g. 90-100 km). If I press the gas pedal to higher speed it will not work, since the car again shake.
For this reason I have to stop the car in park place, get out ignition key, and start the car again. By this reset operation: the problem again appear if I speed much more 120-130km/h, so I have to drive in lower speed.

I go to my Fiat distributor, they claimed that could be a problem on DPF filter, so they cleaned by regeneration it. But this not solved the problem.

Do anybody has the same problem ? Or if somebody can assist/help I will be very appreciate.

Best regards,

 

[Radlet6]

Hello and welcome to the FIAT forum.

I could be wrong, and I wait to see what others say, but if it was mine with this mileage I would be looking at the CV joints. These are a known weak spot on the Croma.

If it is the outer CV joints (the one by the hubs) these are relatively cheap to fix the parts being about €60 per side, the original part number is 46308230 and they are the same both sides.

If the inner joints have gone then this is more expensive as the whole shaft may have to be replaced/repaired.

 

[CromaMkd]

Hello again to Forum members,

Thank you for the valuable answer. I have been changed on 160.000km both outer CV joints that operate without any problem.

To be more specific and to add more information from the last post:
The problem is in fact engine can not be accelerated and engine at whole start to FALTER continuous and very strongly. At this time when problem occurs I see tachometer RPM pointer that also shake up-down that is not constant.

Fiat distributor claims that could be one from the followings:

1- DPF catalysis at whole that is not working properly.
2- Three sensors synchronization procedure between: Exhaust gas temperature sensor, downstream DPF temperature sensor, upstream DPF temperature sensor.
3- Air-Flow meter

But without any exact reason nor answer, this stand only on possibility, that I would ask anybody from the Forum that can help/assist me.

Best regards,

 

[buster]

Hello there,i too have a 2.4 and this sounds exactly like the same fault i had.But you describe it better than me.
I replaced the Egr valve,but this made no difference,i also had two loose injectors in the head.These also were rectifed.Still suffered the same fault.
I gave up in the end,sent it to fiat.According to the bill they carried out a download on the engine and transmision.
Since then i have changed the battery as it was past its date and kept going flat over long periods.
The car now seems fine.I wounder weather it was to do with the battery?

 

[CromaMkd]

Hello again,

I went to also to FIAT and we decide to change AIR FLOW METTER which is from Bosch.

Currently I dont see extreme shaking but I believe since we are winter season. In summer this is happening more often, probably something is heating in some parts.
Do you have also such an observation ? Did you made something to get total solution for this problem till post this message ?

Best regards,

 

[halilson]

I had the same problem today! Very severe juddering and lost power so that I crawled up a hill at 25-30mph (dual carriageway). Once over the brow of the hill it continued, on and off for several miles and then was ok for the remainder of the journey (100 miles). I noticed that the temperature gauge was slightly higher than normal and that the fuel economy had gone down substantially. When I got to my destination I plugged in my laptop and confirmed that it was doing a DPF regen at that time. I think it did another regen on the way home (not had the chance to check yet) but there weren't any problems that time.

 

[buster]

I cant see how a regen could cause this problem,could anyone explain please.My next idea was to replace the maf as it is tied up with the control of the egr.This fault was the reason mine went in for a download.The only problem i get now and again is on the motorway if i put my foot down it sometimes holds back for a split second as if it wants to change down but then doesnt bother.I put this down to the tuning module.I can live with it though.

 

[DoIDon'tI]

Just my hypothesis, accept it or reject it as you wish...at motorway speeds the car is in sixth, at low engine RPM (approx 1500) with the turbo not fully up to speed. The exhaust on all diesel cromas is the same, so despite having a fifth more displacement than the 1.9, the 2.4 has the same exhaust. When the car starts to regenerate under these conditions (assume the DPF is fairly clogged and the intake side of things is similarly clogged up after five years of use), the extra fuel being burned off in the exhaust greatly increases the amount of gas in the exhaust prior to the DPF. This increases the back pressure in the exhaust, which slows down the turbo, which leads to unstable running and vibration/juddering - amplified by backlash in the drivetrain (but that's a different story). If there is another fault on the car (such as a leaking boost hose or faulty boost sensor), this effect will be increased.

Makes sense to me, whether it's what actually happens is anyone's guess

It may be the case that Fiat know about this problem and released updated software to fix it, which is why Buster's car is now OK. Given the lack of faith many of us have in Fiat dealers, the truth may never be known

 

[halilson]

That makes sense, especially when I have an intermittent boost sensor/pipe fault as well. My brother works in a motor factors and he said that the exhausts are the same, which is mad when you think of the extra power involved. A bigger bore exhaust would make a huge difference, I wonder how different the 159's exhaust is? I think the main problem with my Croma is that the previous owners lived in built up areas, with very little opportunity to give it a regular blast. They probably used supermarket diesel too, which doesn't help. A few weeks of v-power and a heavy right foot will hopefully sort it :O)

 

[halilson]

Just stumbled across this on the Alfa Forum:

http://www.alfaowner.com/Forum/alfa-159-brera-and-946-spider/231110-juddering-during-regen.html

It seems that juddering during a regen is quite common on the 2.4. Not seen a thread with a cure yet tho...

 

[buster]

Please,please dont take my post to be obtrusive i was just wondering,im far from gened up on these things.when you look at it like that it is possible.Mine would do it about every fourth day,and from a standing start when not quite fully warm.The first thing the dealer said to me was the inlet manifold flaps could be the problem,needing a new manifold to cure it!Lets hope it is just a regen happening.

 

[halilson]

Quick update. Car was long overdue for a regen (86% according to ecu) so I took it out for good run and the vibrations appeared again, very briefly. On returning home I plugged the laptop in and it was in the middle of a regen. They are getting significantly less intense, which I am assuming is down to better quality fuel and a decent clean of the fuel system. I have just bought some Forte DPF cleaner to try. I will keep you informed.

 

[keithglos]

When my 2.4 does a regen, it uses almost twice the fuel. You can check this with the instant MPG display. Without that I would possibly not know it is doing it.

 

[Caravadossi]

When my 2.4 does a regen, it uses almost twice the fuel. You can check this with the instant MPG display. Without that I would possibly not know it is doing it.

Another indicator is - if you flick-to [range] it shows quite a knock-back. I had a re-gen kick-in last winter when low on fuel & re-turning to base late at night. Suddenly I lost the remaining range that I thought would get me home - fortunately in the morning I made it on fumes to a garage to refuel.

Then there's the distinct whiff of diesel & burning.

----------
55 1.9/16v150 Prestigio
120222

 

[halilson]

I keep it on range too, I find it jumps about too much on instant consumption! Hopefully, after a bit more tlc, I won't notice the regens any more either :O)