Technical Running lumpy after warm-up

[bigdong]

Hi, Can anybody help with this one?
1.9JTD "56" plate 125k miles. It runs really well for the 1st 5 miles then it feels as if it's dropping onto 3 cylinders and smoking like mad. It had DPF replaced as it was choked solid and ran brilliant for the next 10k before this started. Any help appreciated.

 

[Ffoxy]

Try running some diesel engine cleaner through it for starters. Usual suspects can be MAF sensor, EGR valve or contaminated fuel. Injectors can give a problem too. If it runs OK at first until its at running temperature you could check the coolant temperature sensor, if that fails it can cause fuelling issues.

 

[beauxreflets]

Hi, Can anybody help with this one?
1.9JTD "56" plate 125k miles. It runs really well for the 1st 5 miles then it feels as if it's dropping onto 3 cylinders and smoking like mad. It had DPF replaced as it was choked solid and ran brilliant for the next 10k before this started. Any help appreciated.

1. Does the Diesel Fuel filter need changing.
2. Fuel Temperature Sensor malfunction in Fuel pump, where the Diaphram is unable to operate efficiently and becomes unbalanced; as to much fuel/contaminated (water etc.), has crept in behind limiting the movement when the engine has warmed up).
3. MAF sensor sticking
4. EGR valve could be choked up.

 

[bigdong]

Hi Folks, Thanks for the replys so far. The doblo has a new fuel filter and has had additive through the fuel. I need to try other sugestions so all further sugestions will be appreciated. It does feel more like it's droping an injector after it warms up but I cant be sure this is the case. If this rings bells with anyone please advise. Thanks BD

 

[beauxreflets]

1. Does the Diesel Fuel filter need changing.
2. Fuel Pressure Sensor malfunction in Fuel pump, where the Diaphram is unable to operate efficiently and becomes unbalanced; as to much fuel/contaminated (water etc.), has crept in behind limiting the movement when the engine has warmed up).
3. MAF sensor sticking
4. EGR valve could be choked up.

 

[Yobbo]

I had something just like this many years ago caused through slightly low compression on one cylinder and the secondary glow plug circuit disguised the problem.

It was on a battered old diesel Cavalier I owned with over 200k on the clock. It would start ok'ish (never easy) and then run well for the first few miles but then start to run on 3 and a half cylinders after about 10 minutes.

Reason was slightly low compression on one cylinder due to a tappet gap having closed up because a valve seat had recessed into the head slightly which reduced the compression. I think the car had hydraulic tappets so it wasn't immediately obvious that there was no gap. The cars secondary glowplug circuit would run for about the first 10 minutes or so and that was helping that cylinder burn fuel, as soon as the ECU switched off the secondary circuit the engine was reliant on compression only to ignite the fuel in that cyclinder and that was when it played up. Took ages to work out what was going on in our workshop.

Obviously this is unlikely, but you can get some strange things happen on any vehicle