from Goss’ Garage by Pat Goss

“It’s the little things that count,” and that’s sure true on cars. For many of you if it’s small and it’s out of sight you and your technician disregard it. After all, small parts can only cause small problems, right? If you believe that one I have some low tide property you should love. Lately I’m seeing lots of cars with performance or no start problems caused by small out of sight parts, fuel filters. It’s a new phenom probably caused by ethanol now used in our gas.

Although many owners’ manuals don’t suggest regular fuel filter replacement it is a very good idea. Last week we had several cars towed in for no-start or severe performance problems and in each the main failure was a filthy fuel filter. Two had either dishonest or stupid estimates from shops ranging from nine hundred dollars to replace a catalytic converter to over seven thousand dollars for major engine repairs.

Symptoms caused by fuel filters range from hesitation during acceleration, to hard starting, to a no start condition and everything in between. A bad fuel filter can also cause an illuminated check engine light.

Because there are so many symptoms associated with fuel filters it’s best to avoid problems and unneeded expense by replacing the filter every year. Unfortunately this isn’t practical on all vehicles as some jackass manufacturers elect to put the fuel filter inside the fuel tank requiring massive amounts of labor to replace it.

Fortunately there is a simple solution, replace your fuel filter when you have a performance issue, a fuel related no start or a check engine light combined with a fuel or catalyst code. Here’s how it works, when the fuel filter becomes clogged with junk the amount of fuel that can flow through it is reduced or blocked entirely. Of course blocked entirely means no start but restricted flow causes your car’s computer to make adjustments to compensate for the lack of fuel.

In many cases the computer can compensate so you don’t feel anything but if the condition persists the computer will eventually set a fuel related code and turn on the check engine light. The code might suggest a problem with an oxygen sensor, MAF sensor or catalytic converter efficiency and your nightmare begins.

You mistakenly follow the myth that to correct check engine light problems you read computer codes and replace the parts the codes refer to. But codes don’t actually tell what’s wrong only what is being affected by what is wrong. But you don’t know this and neither do a lot of neophyte technicians; so you head for the nearest place offering free code scans.

Then you or your technician install the parts referred to by the codes. Finally one battery cable is disconnected with the mistaken notion that this will erase codes. Actually the only thing that can erase codes is the computer seeing two successive trips without problems. Disconnecting the battery just erases the computer’s short term, learned memory, which temporarily turns the light off. But at some point the computer relearns what was erased and when it does the check engine light is back on. So you start over with another round of codes, mistakes and parts but after lots of wasted money the light is back again. Hopefully this teaches you that codes are not the answer and that free code scans are usually worthless and frequently very costly!

The lesson: if you experience any of the above symptoms begin by checking the fuel filter for blockage. A stopped-up filter can cause numerous issues and it is far too often out of sight, out of mind and totally ignored during problem diagnosis.

Published in by CARCHEX on November 13, 2014