Roadside Diesel Repair

Contamination
More commonly, the first sign of trouble develops not long after refueling your truck. This would indicate in most cases some sort of fuel contamination. Keep in mind that the fuel filters, lines, and pumps can hold as much as a gallon of fuel. This means that your truck can go anywhere from five to 20 miles after a refuel before trouble develops.


If you feel that you have some sort of fuel contamination, then the first order of business is to find out what the contaminant is. Water is the most common trouble. Water can build up over days, or if there is enough water in your fuel tank, it can shut you down right away. It can get there by any number of means. Condensation can build up from high humidity, and slowly contaminate your tank until there is enough to start working its way through the fuel lines. A heavy rain can push past the seals on your fuel cap, or even worse, past the fuel tank covers at the gas station.


Fortunately, your diesel has a fuel separator. In almost all cases it is part of one of your fuel filters, and it even has a drain on it just to evacuate the water. To remove the water from the separator of most trucks, simply open the valve and let the water run out until you see clean fuel. Some earlier Fords have a separator that is not part of the filters, but it behaves in a similar manner. For some Chevrolet models, it is necessary to open upper and lower valves on the filter to allow the filter to drain completely, then close the lower valve and crank the engine with the fuel shut-off solenoid disconnected until fuel comes out the top valve.


Disconnecting the fuel shut-off solenoid allows the low-pressure pump to push fuel without the engine starting since the injector pump is inoperative. At this point, the air and water are bled out, the top bleeder can be closed, the wire for the shut-off solenoid reconnected and the truck restarted.

Total Drain
However, if you are anything like us, the sound of draining fuel or pumping fuel all over the engine might not sound so great. It is also a task that is hard to accomplish on your own, since it is not always possible to see the filter or drain valves when you are at the ignition switch. Sometimes gravity alone will not pull all of the water out of the separator. For these reasons we like to use the previously mentioned vacuum pump to suck the water or contaminated fuel out of the drain valve openings. Simply use the brake bleeding attachment for the pump and it will pull any air, water and contaminated fuel into a clear and sealed container. This method is much cleaner, provides better results and it does not wear out your batteries with excessive cranking.