question, dirty fuel filter and fuel efficiency impact?

SFHLibertyCRD · **Posted:** Tue Apr 22, 2014 6:25 pm

Hi all, sorry if this is a stupid question (I'm not a mechanic). I am about to change the fuel filter soon since I don't have any idea when/if it was changed by the PO (judging by the air filter condition, I doubt it has been changed any time recently). I also run higher blends of biodiesel as well, so it is likely getting caked up with some stuff from the tank and fuel system.

My question is, I have been seeing lower and lower MPGs lately. That is partly due to lots of short trips (but I have also never been happy with the 26-27 max hwy that I have gotten). I'm assuming any kind of fuel restriction impacts MPGs, is that the case for a dirty fuel filter also?

flman · **Posted:** Tue Apr 22, 2014 6:37 pm

SFHLibertyCRD wrote:

Hi all, sorry if this is a stupid question (I'm not a mechanic). I am about to change the fuel filter soon since I don't have any idea when/if it was changed by the PO (judging by the air filter condition, I doubt it has been changed any time recently). I also run higher blends of biodiesel as well, so it is likely getting caked up with some stuff from the tank and fuel system.

My question is, I have been seeing lower and lower MPGs lately. That is partly due to lots of short trips (but I have also never been happy with the 26-27 max hwy that I have gotten). I'm assuming any kind of fuel restriction impacts MPGs, is that the case for a dirty fuel filter also?

How aggressive are the Yokohama Geolander A/T-S LT225/75R16 tires? I run a the OE Wranglers on the work horse, and Michelin Highway AS on the garage queen. It gets me a couple MPG extra.

SFHLibertyCRD · **Posted:** Tue Apr 22, 2014 6:42 pm

flman wrote:

How aggressive are the Yokohama Geolander A/T-S LT225/75R16 tires? I run a the OE Wranglers on the work horse, and Michelin Highway AS on the garage queen. It gets me a couple MPG extra.

flman, they're D-load rated, max pressure of 60psi. I usually keep them around 50 or high 40s for driveability. I suppose if I factored in 2-3 mpgs lost due to tires, I might be closer to the range I would hope for. I'm still not entirely convinced that is all that's going on though. Check out my fuelly for some detailed logs of my driving since purchasing in PA and driving cross country back to CA.

flash7210 · **Posted:** Tue Apr 22, 2014 9:16 pm

Things that will hurt your fuel mileage:

Dirty air filter
Dirty fuel filter
High % biodiesel
Large heavy tires
Lead foot

BTW, I average 27 mpg, city/highway, every day.
I'd say your doing pretty good.

SFHLibertyCRD · **Posted:** Wed Apr 23, 2014 12:35 am

flash7210 wrote:

Things that will hurt your fuel mileage:

Dirty air filter
Dirty fuel filter
High % biodiesel
Large heavy tires
Lead foot

BTW, I average 27 mpg, city/highway, every day.
I'd say your doing pretty good.

Air filter, changed. Fuel filter next. Believe it or not, I've had higher fuel efficiency on B100 then on D2. It doesn't make sense to me but its happened frequently enough.

If I had 27 mpg mixed city/highway, I'd be thrilled. My mixed driving is usually in the low 20s. 27 was my all time max, driving all highway across the USA, when I would have liked closer to 30.

flman · **Posted:** Wed Apr 23, 2014 6:38 am

flash7210 wrote:

Things that will hurt your fuel mileage:

Dirty air filter
Dirty fuel filter
High % biodiesel
Large heavy tires
Lead foot

BTW, I average 27 mpg, city/highway, every day.
I'd say your doing pretty good.

Brakes sticking?

SFHLibertyCRD · **Posted:** Wed Apr 23, 2014 1:11 pm

flman wrote:

flash7210 wrote:

Things that will hurt your fuel mileage:

Dirty air filter
Dirty fuel filter
High % biodiesel
Large heavy tires
Lead foot

BTW, I average 27 mpg, city/highway, every day.
I'd say your doing pretty good.

Brakes sticking?

What's the easiest way to check for that? Jack it up and spin each wheel in neutral?

Mountainman · **Posted:** Wed Apr 23, 2014 1:14 pm

Starting with cold brake rotors, drive a mile or two and coast to a stop without using ANY brakes, and put your finger on the rotors. Mine are warm :banghead:

SFHLibertyCRD · **Posted:** Wed Apr 23, 2014 1:22 pm

Mountainman wrote:

Starting with cold brake rotors, drive a mile or two and coast to a stop without using ANY brakes, and put your finger on the rotors. Mine are warm :banghead:

Hmm. That is very hard to do in an urban area. Any other suggestions on how to test? I do suspect I might be getting some rubbing.

thermorex · **Posted:** Wed Apr 23, 2014 3:12 pm

SFHLibertyCRD wrote:

Mountainman wrote:

Starting with cold brake rotors, drive a mile or two and coast to a stop without using ANY brakes, and put your finger on the rotors. Mine are warm :banghead:

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Hmm. That is very hard to do in an urban area. Any other suggestions on how to test? I do suspect I might be getting some rubbing.

Get to an empty parking lot or wait till evening, I have a street nearby I live with a 35 mph limit, after 8 PM there are probably 20 cars in an hour driving there.

thermorex · **Posted:** Wed Apr 23, 2014 3:16 pm

Mountainman wrote:

Starting with cold brake rotors, drive a mile or two and coast to a stop without using ANY brakes, and put your finger on the rotors. Mine are warm :banghead:

Remove the rubber sleeves that are on the lower pin (I think) in the caliper, since I did that I had no issues with brakes. You may hear some noises every now and then but not a big deal. Also, grease the pins very well with ceramic grease (it's usually purple) that thing does not dry and also is not washed by water as easy.

question, dirty fuel filter and fuel efficiency impact?

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