Fuel Filter and Mileage....

jmoomaw · **Posted:** Tue Nov 25, 2008 9:56 am

I have had a steady decline in mileage. It started at 26 mpg and I am down to 21.5 mpg. I have replaced the CAC Hoses, MAP/Boost Sensor, Provent and SEGR.

I have run B5 for a tankful. Does the fuel filter effect mileage? I find it strange that the more I do to improve the running of this baby, the poorer the mileage is.

ATXKJ · **Posted:** Tue Nov 25, 2008 10:08 am

If you haven't changed the fuel filter recently (20K miles? - depending of fuel quality) it's a good thing to keep clean.

but I think the general comment was Air Filter affects mileage, Fuel filter affects performance
although in New York in November - I'm expect cold weather to be impacting your mileage
1) winter fuel - don't know when they start blending - but it's significant
2) warmup - whether idling or the viscus heater kicking on
3) on defrost the AC compressor turns on.
4) air is denser - therefore it takes more energy to move through it.

retmil46 · **Posted:** Tue Nov 25, 2008 11:01 am

Add fuel temperature to that list of cold weather items that will affect mileage.

With the fuel temp sensor and ECM, if the fuel is too cold or too hot - outside of the "comfort zone" that the ECM wants to see - the ECM will adjust fueling on this beast such that fuel mileage drops like a rock. And without a lift pump, the CP3 has even more of a workout sucking cold thick fuel thru the filter.

Best guess from what I and others have seen is this beast likes it's fuel to be somewhere in the 80 to 120 F range for best mileage.

Last New Years coming back from Texas, with temps in the teens and 20's, I forgot to cover over the fuel cooler in the return line. Mileage dropped like a rock down to 20 to 22 mpg. Once I tumbled to what was going on, covered over the cooler and let the fuel tank warm up somewhat, mileage shot back up to 30 mpg.

Short term suggestions - get a Fia grille blanket or some other type of grille blocker to cut down on air flow thru the front - the warmer that engine is, the better mileage it will get - and try plugging in your block heater for at least a couple hours before driving to cut down on warmup time.

gmctd · **Posted:** Tue Nov 25, 2008 12:57 pm

Exactly: idle warm-up time is zero mpg............

jmoomaw · **Posted:** Tue Nov 25, 2008 5:29 pm

I always wondered why the 18 wheelers covered up their grills.....Guess it is time to do mine. Here in NY we have been hovering around 30 degrees for two weeks now....20 degrees below normal..

Yuck...

ATXKJ · **Posted:** Tue Nov 25, 2008 10:04 pm

This was the thread on the FIA blanket - I thought about it - but not enough of an issue in Texas
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?t=27110&highlight=thingy

nursecosmo · **Posted:** Wed Nov 26, 2008 4:50 pm

I bought the Fia blanket last year for my move to WI. The coldest temps I saw was 12 degrees below 0. The blanket does not produce a noticeable effect on warm up time or mileage that I can detect but it sure looks cool.

Cowcatcher · **Posted:** Wed Nov 26, 2008 5:20 pm

When it starts dropping below 30 plugging in the block heater helps some too. Also you might want to plug your fuel heater back in if you have unplugged it for fear of overheatiing on fuel starvation in the summer.

jmoomaw · **Posted:** Wed Nov 26, 2008 7:48 pm

I would love to plug in my fuel heater. I will have to look in the owners manual. Is that standard? Hope so.

I ordered the winter blanket today. Had a birthday check from my sister in law so I called her to thank her for the thoughtful gift!

bdptp73 · **Posted:** Wed Nov 26, 2008 7:55 pm

jmoomaw wrote:

I would love to plug in my fuel heater. I will have to look in the owners manual. Is that standard? Hope so.

I ordered the winter blanket today. Had a birthday check from my sister in law so I called her to thank her for the thoughtful gift!

I think Dave ment the plug on the filter head, if you unplug it in the summer.

Cowcatcher · **Posted:** Mon Dec 01, 2008 12:18 pm

Yes, I meant the fuel heater on the filter head. Also the block heater. They all came with block heaters with the 110V cord tie wrapped somewhere. Most of the '06's it was tie wrapped to the dip stick tube.

DOC4444 · **Posted:** Wed Dec 03, 2008 8:07 am

How do you go about covering the fuel cooler in the return line? (Already have a FIA blanket.) Also, pulling the viscous heater relay out really helps mileage (3-4 MPG+) inbelow 35 degree F weather.

Thanks,

DOC

Joe Romas · **Posted:** Wed Dec 03, 2008 8:29 am

DOC4444 wrote:

How do you go about covering the fuel cooler in the return line? (Already have a FIA blanket.) Also, pulling the viscous heater relay out really helps mileage (3-4 MPG+) inbelow 35 degree F weather.

Thanks,

DOC

Unless you or someone before you put a "fuel cooler" on you don't have one to cover :lol:

Fuel Filter and Mileage....

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