A few weeks ago many of you disagreed with Pat goss on what he said about many check engine lights being on do to clogged fuel filters. I recently asked Pat to confirm and explain why he feels this is so. Here is his response. I thought it was a very good explanation. What do you think?
We see a lot more fuel filter problems. For one thing the ethanol attracts and absorbs water to the fuel system which in turn causes corrosion on metal parts. Ethanol can also strip minuscule particles of plastic from the surface of plastic fuel tanks and parts. Both problems are especially bad if the driver does not use Isopropyl alcohol dry gas to control moisture.
But the larger issue is that ethanol is hygroscopic so there is more water in most fuel tanks. Some water can be absorbed into the gasoline but some will settle to the bottom of the tank. When water is present there will usually be growth of micro organisms such as water bottom blooms, mold, fungus, bacteria and algae that live in a mostly anaerobic state in petroleum products. They are water or airborne and enter through vents, condensation or with fuel from underground storage tanks.
These life-forms mostly live in the water at the fuel-water junction layer and feed on hydrocarbons in the fuel or starch-like substances in the ethanol. Some create hair-like mats on tank bottoms, others are slimy and are suspended from the fuel at the fuel-water interface. Like all living things they produce waste which causes sludge, acids, and other nasty stuff that can damage fuel system parts.
These organisms reproduce at an astounding pace but as individuals are short lived and quickly die. Because they are microscopic they and their excrement can pass through the sock on the end of the fuel pickup tube but are trapped in the fuel filter's much finer pores. This is what makes the average fuel filter look muddy. Again, ethanol comes from a starch and offers a potentially better food source for a wider variety of micro life-forms. More critters means more dead carcasses and more poo which means shorter fuel filter life.
Also when too much moisture accumulates in the tank it can lead to phase separation of the ethanol causing damage to both metal and plastic. The residue from this reaction clogs filters as does the rust from the moisture reacting with metal parts.
In the past we had much less of this. Although MTBE was hazardous to us it didn't cause nearly the problems to the cars that we see with ethanol.
