W210 320CDI rough idle - injector? MAF?

[mattsurf]

My E320 CDI has developed a very rough idle - feels like it is only on 5 cylinders at tickover. Also I notice that the economy has fallen significantly - last night drove from Birmingham to Gatwick - set the cruise at 70mph and achieved 38mpg, the last time I did this the car ran at 43mpg (even though it was summer)

I cannot detect any drop in power or flat spots, however, the engine is so powerful it is hard to tell.

I suspect a failed injector - has anyone else experienced similar problems. Should I consider getting all of the injectors done (the car has 120k miles) or just the failed on (if it is the injector). Also does the MAF fail suddenly or does it degrade in performance - if so what are the signs

Thanks

Matt

 

[television]

Hi Matt, the MAF does nothing at idle so it looks like injector problem, there are firms that re con them much cheaper than new

 

[wingco]

I have the identical car (100k miles) which had an identical problem to yours. Proved to be the No5 injector. Had it changed and perfect ever since (175quid for a recon part). The Merc specialist I use advised me to only change the dodgy one, as in his experience the others can last years longer.

 

[television]

I have the identical car (100k miles) which had an identical problem to yours. Proved to be the No5 injector. Had it changed and perfect ever since (175quid for a recon part). The Merc specialist I use advised me to only change the dodgy one, as in his experience the others can last years longer.

This is very true, do not do what does not need doing, for the may never need doing

 

[mattsurf]

Spoke to local Indi - he agrees probably is an injector. However, he recommends Bosch injectors (at £250 each), he has not fitted recon injectors. Can you recommend an Indi who has fitted recon injectors, or know of a supplier who can supply them

Thanks

Matt

 

[mattsurf]

Another question - what is the part number for an 1999 E320 CDI injector.

Matt

 

[Aussie Nick]

Maybe you want to try running some serious injector cleaner through with the diesel for a couple of tank fills. It worked on my tractor. If you get the right stuff it will be as good as new and also clean out the other injectors as well. Sure beats paying 250 pounds .

 

[television]

Feather diesel services in Halifax do the recon injectors

Why pay double the price

01322 387800

service@feather-diesel.co.uk

 

[hmang]

http://www.uniteddiesel.co.uk/diesel_injectors/mercedes_benz/

 

[mattsurf]

Filled the car up last night - seems to be fine on new tank of diesel. So now thinking that maybe that the fuel might have been a bit suspect (Strangely I filled it up with Shell ultimate diesel by accident which cost 110.9 per litre) could it be that there is something in the Shell fuel that the car doesn't like?

I will keep a close watch on the problem to see if it occurs again

 

[Aussie Nick]

I ve had the same experience with the lower priced shell fuels. My son wont go anywhere near the shell which causes his BMW motor to ping. Suggest you still try the good quality injector cleaning additive.Try using Mobil Fuel

 

[mattsurf]

My car seems fine on the Texaco stuff - garage is 1/2 mile from home and pretty much the cheapest around

I certainly intend to try some quality injector cleaning additive - I think that an injector is getting towards the end of its life and is more sensitive to fuel quality as a result - I could squeeze an extra few thousand miles before having to change it. Ran the car for 20 miles around town ferrying kids to rugby then 2 birthday parties - the car ran beautifully - I also tried a pretty hard accelleration to 60 again pulled like a train no hesitation and it ran to the red line with no noticable problems. I think that I will put the problem down to the diesel and watch it closely.