stephen ingham

Hi all I run a 2006 ML320 cdi (w164) and wondered if anyone can suggest a reason for poor fuel economy?
I went on a 100 mile round trip yesterday and the trip computer was showing 27mpg at best, surely I should get better on motorway mileage?
Can anyone suggest a cause and possible fix?
Any help or advice would be much appreciated

Plutoe

If you really want to go through the expense for a more correct answer---do a leak oil test. If you want to simply FA change the intake air filter. If you don't GAS, don't worry about the one sample test that is not representative--by the girlfriend a holiday hotdog!!

stephen ingham

Hi, thanks for the reply.
Sorry to be a little dumb but I don't understand your answer apart from changing the air filter, It currently runs on K&N panel filters.
What do you mean by a leak oil test?

Cheers
Stephen

Plutoe

A leak oil test is the MB test to determine the condition of your diesel injectors-google the test!!

20swrt

Post a photo of your middle cluster. It will give us a better idea of what was your average speed before you last fill-up. The CDI can go between 550-600 between fillups. Getting 27mpg for 100 miles is "normal".

marc hanna

How fast were you going?

C230 Sport Coup

27 mpg sounds good, but what do I know. Normally getting 17-22 with gas version.
What do you normally get?

stephen ingham

I was going about 70mph

marc hanna

In my opinion, that's good economy for that speed. You will notice a significant improvement, just dropping down 5mph. As we drive faster, it takes an exponential increase in power. My personal best is 33.6mpg (7L/100km) @ 62mph (100km/h), but I also have my EGR disabled.

stephen ingham

Did you disable the egr through the software or other means?
I would like mine disabled but don't really want it remapped to have it done, am sure I once saw a post about being able to unplug it and plug a resistor in its place...

marc hanna

Software. See:

Green Diesel Engineering