General Engine misfire

[Colin R]

My 2003 Multipla 115 ELX 1.9 diesel has a slight misfire. It has a noticeable judder at idle and is noisy. It performs well enough, but only returns 36 m.p.g. & I don't use it for short journeys. I've taken the car to 7 garages and nobody is able or willing to diagnose the fault. I'm told the car will not communicate with their computers and it will cost more than it's worth. 5 have turned the job down and 2 have given estimates of £1K. It's only done 90K miles & is in VGC otherwise. The injectors have been tested and are fine. This doesn't seem to be a common fault with the diesel engine. Does anybody have any views on what may be causing it or how I can get the car to communicate. I'm getting to the point where I feel no-one will commit to fixing it which leads to my second question. I have a 2002 110 ELX with a good engine. Is it compatible with the 115 ELX? Can I take the engine out of the older car and plant it in the 115 ELX? Any help will be appreciated. Colin.

 

[widemouthfrog]

At what revs do you get the misfire? Does it do it all the time, or just under load?

Judder and noise at idle could well be the crankshaft pulley. Check the condition of the rubber part in the middle of it. Fuel consumption could be a number of things, but clean the MAF and MAP sensors for a start, and try blanking the EGR as well.

 

[Colin R]

Thanks for reply. I'll follow your advice re the sensors. The misfire is present from the time the vehicle starts. It is most noticeable at that point. The car starts with a shudder. Last year an engine mounting broke in two and had to be replaced. I think it was because of the rocking of the engine caused by the misfire. The juddering appears to diminish when revved and when in motion it is not apparent, but clearly from the poor MPG it is still present.

 

[widemouthfrog]

Sounds very much like a shot crankshaft pulley. It makes the engine feel very lumpy at idle and up to about 1,000rpm, then smooths out. Buy a good quality one (genuine Fiat, Gates, Febi Bilstein or Contitech come to mind) and have that changed before doing anything else.

Expect to pay about £70 for the pulley and its 4 screws. Fitting shouldn't take more than 30-40 minutes, max.

And don't come to me for a refund if it proves not to be the pulley.......

 

[Colin R]

Many thanks for your advice Widemouthfrog. Your description of the sympton sounds about right. The car chugs at idle. The noise (rattle) comes from the left side of the engine where the pulleys are positioned. Don't worry I won't blame you if it doesn't work!

 

[boilermansab]

Some selling on eBay cheap.

 

[boilermansab]

Don't assume expensive is better.
I had a genuine fiat one fail after 14 months

 

[Colin R]

Thanks Boilermansab.