At about 11k miles on the ticker, my MPG started dropping off to the tune of 2-6mpg. I was a little perplexed by the whole affair at 12K, I decided to stop by the local Cummins shop and pick up a fuel filter (only about $12.00 vs $40.00 @ the dealer). The counter guy said a dirty filter could make a difference. I was skeptical, but had to start somewhere.

It was pretty easy to change & man was it worth it. My filter was BLACK. I couldn't belive how much better it ran...it was like a new engine, & my mpg at 55 jumped up to 24 from a max of 18 before just before the change. I guess the performance just kind of dropped off over time so I didn't notice it.

Anyway, looks like I'll be changed my filter every 10K-11K vs the recommended 15K. Maybe our fuel around here has more dirt in it than average.

 

It kinda goes against the laws of physics though.

Less fuel flowing through the filter results in more being consumed by the engine.


Change mine every other oil change, which ends up being every 10K.
First change it was quite black, subsequent changes have been a dark gray.



phox

 

I feel the same in that regard , we have to be missing something here ! I can understand loss of power.

 

Must be some kind of efficiency thing...

 

less flow ='s less presure, which ='s a corser injector spray, which ='s less power, which ='s crap for mileage.

If we were dealing with carburators, less would be more But injectors need presure to say effecent.

 

Ahhh, perfect explaination!