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Old 01-25-2010, 08:46 AM   #1 (permalink)
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Does dirty fuel filter cause bad economy?

Hello.

I have read on various forums that people have experienced better fuel economy after changing their fuel filters.

I'm wondering, how can a dirty fuel filter cause the vehicle to use more fuel?
wouldn't it use less?

Thanks.

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Old 01-25-2010, 08:48 AM   #2 (permalink)
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It can cause you to have worse, but most of the time it doesn't. (at least in my case)
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Old 01-25-2010, 09:04 AM   #3 (permalink)
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Thanks,

I'm wondering though, what is the technical explanation behind it causing bad fuel economy.
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Old 01-25-2010, 09:39 AM   #4 (permalink)
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If the filter is clogged, it won't run. If it's restricted, it simply makes the pump work harder.
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Old 01-25-2010, 04:19 PM   #5 (permalink)
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Quote:
Originally Posted by Z2TT View Post
Hello.

I have read on various forums that people have experienced better fuel economy after changing their fuel filters.

I'm wondering, how can a dirty fuel filter cause the vehicle to use more fuel?
wouldn't it use less?

Thanks.
Z2TT,
A dirty fuel filter makes no difference to economy but it usually restricts the upper rev limit simply due to lack of flow.

Totally blocked the filter simply stops the engine since fuel can't get through.

Pete.

Last edited by Peter7307; 01-25-2010 at 04:26 PM..
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Old 01-25-2010, 04:35 PM   #6 (permalink)
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By trying to keep the engine running, the natural impulse is to add more throttle. So to make up for the restriction we try to add more fuel by pumping the accel pedal. So for instance instead of having the engine cruise at let's say 1500 RPM we overcompensate & the result is a fluctuation in overall engine speed 1250 to 1750 to 1400 to 1600, just trying to keep a steady 1500.

Dave
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Old 01-25-2010, 05:18 PM   #7 (permalink)
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If only K&N made fuel filters- think of the power and economy!!!
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Old 01-26-2010, 08:18 AM   #8 (permalink)
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I thought the dirty air filter thing was from back when cars were carbureted. Doesn't a restriction in airflow act as a choke, making the engine run rich?
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Old 01-26-2010, 08:48 AM   #9 (permalink)
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Frank Lee, what is your reasoning behind the K&N fuel filter. I run a K&N air for my truck, I noticed a difference right away. Is it an ultra low restriction gas filter?

Dave
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Old 01-26-2010, 09:10 AM   #10 (permalink)
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Quote:
Originally Posted by Frank Lee View Post
If only K&N made fuel filters- think of the power and economy!!!
...DANGER, Will Robinson, DANGER!

...if you use both a K&N air filter and a K&N gas filter, you'll save so much gasoline that it will backup and overflow the gas tank capacity, causing hydrocarbon air pollution and a fire danger (wink,wink)!!!

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