Uh-oh! engine code: check fuel filter

Updated Mar 24, 2012

I learned today what the inside of our truck’s fuel filters look like. Learned by having them cut them open and looking.

Diane and I are in drive/sleep mode on a cross country run. Just as she was pulling into a truck stop for fuel, a code appeared on the dashboard saying “check fuel filter.” We have been in this truck over five years and this is the first time that code has appeared.

The truck was running fine. Fuel economy sucked but we attributed that to the strong headwind we have been dealing with all day. While we have never had a fuel problem in eight years of expediting, we are prepared for one. We carry extra fuel filters, wrenches and a siphon hose in the truck where we can get at them even if the truck body (box) is sealed under load.

Do we ignore the code and drive on? Do we clear the code and drive on prepared to deal with the code if it reappears? Do we drive on prepared to change the fuel filters on the side of the road if a real fuel problem develops? Do I change the fuel filters now in the truck stop parking lot? Do we spend some money and have the truck stop shop change the filters now?

There really wasn’t any question. We are under load. That’s not a time to leave fuel issues to chance. We had no idea why the fuel filter code appeared. Changing the fuel filters might solve the problem, but what if it did not? Maybe it was a bad sensor. Maybe it was a bad filter. Maybe it was bad fuel. Whatever it was, I’d rather find out when we are in a truck stop than on the side of the road. We went to the shop and had the fuel filters changed.

It has been less than 10,000 miles since the fuel filters were last changed. At my request, the filters were cut open for inspection. There are two fuel filters on this truck. The fuel/water separator filter was black inside but had no debris or goo. The other filter was clean. The mechanic said that fuel and water came out of both filters when he removed them but he did not show me, and I did not have full confidence in him or his report.

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Our truck has been run very little in the last two months while we have been on vacation in Florida. We took it out for an exercise run every couple of weeks or so and it ran fine. Did condensation build in the tanks then? Did the STA-BIL fuel treatment I used before we parked the truck in Florida contribute to the fuel issues we had today? What about bio-diesel? We try to avoid that when we can but have no choice in some states where it is legally mandated. Did bio-diesel have an effect? Had bacteria grown in the fuel tanks while the truck sat in Florida? Maybe we just got a dose of bad fuel. We have heard many stories from truckers about that. Is that what happened to us today?

Lots of questions, no real answers. Readers, I am open to suggestions.

With new fuel filters and newly-filled tanks we continued our journey. Our fuel economy improved when the wind died down after sunset. The truck ran fine. We expect to make the Monday morning delivery as scheduled.

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