"[You] mainly need to worry about three things when it comes to maintaining [your] fuel system," says Francis at Deere.
"Draining the water separator at the appropriate intervals, replacing the fuel filters at the manufacturer's specified intervals, and using only manufacturer-recommended fuel filters. For example, if you purchase a fuel filter that doesn't meet the engine manufacturer's specifications, that filter might not have the right micron rating, and today's diesel engine fuel systems have become less tolerant of contamination. This means it's crucial to change the fuel filter on time and to buy the correct fuel filter."
Francis adds, "If you don't change your filter according to the manufacturer's specifications or if you use the wrong filter, you can fail the high-pressure pump or you can fail the injectors. Also, if you don't check the water separator and therefore let water into the fuel system, components can fail. Once they've failed because they've become contaminated, they almost always need to be replaced."
Ellison adds his own suggestion: "To make equipment more fuel efficient, be sure the exhaust and intake restrictions are within limits." To that end, he recommends periodically checking the exhaust pipe for kinks and bends. Likewise, the air filter needs to be changed according to the manufacturer's recommendations.
"Change it; don't clean it," he advises. "A number of customers try to clean the air filter and wind up tearing it, which allows dirt to enter directly into the engine, which can score the cylinders. It's not always easy to see these tears, so it's always best to change the filter instead of cleaning it."
He adds, "Operators should do a daily visual inspection of the air filter to ensure all joints and clamps are secure and that it's in good working order."
You get out what you put in
According to Crenshaw at Kubota, diesel engine fuel efficiency is greatly affected by the fuel itself. He recommends using only clean, uncontaminated fuel of known quality. Fuel that is dirty can clog fuel filters and get into the injection pump or the injector itself and cause performance problems. "Having good, clean fuel quality is key to maintaining any fuel system efficiency," he states.
As mentioned previously, one of the most common contaminants found in fuel that has been stored incorrectly or for long periods of time is water. Crenshaw says that water in diesel fuel can create algae. Equipment owners should be sure to check the water separator on their engines daily and drain them, if necessary.
"Lots of customers say they don't get adequate life from their fuel filters, but this is mostly due to the quality of their fuel," says Ellison at Cummins. "If you're storing fuel for a long time or if there is any chance you have a leaky tank, you need to treat your fuel with an anti-microbial agent."
In addition to fuel quality, the type of fuel used is important to fuel efficiency as well. "There is a difference between winter and summer fuel," says Ellison. "Winter fuel, if blended, will be 8 to 10 percent less efficient than summer fuel because it is a lighter, thinner fuel. There's a 5 to 10 percent increase in usage to get the same performance."
Using the wrong fuel for the season can affect performance. "If you use summer fuel in the winter, for example, your fuel will turn to Jell-O as the wax crystals gel. This can clog the fuel filter."
In general, it's not just the fuel that should be pure but everything involved with maintaining the engine in order to achieve optimum fuel efficiency. "If dirt gets into the injectors, you can have injector ‘hosing' where a steady stream of fuel is sprayed; no atomization," explains Ellison. "This can melt the top of the piston which can lead to a scored cylinder and a major overhaul."
He continues, "A number of customers, when they change their filters, will pour fuel out of a dirty can into the clean side of the filter, which goes directly into the injectors. You should always pour into the dirty side or use very, very clean fuel."