What Are the Causes of Common Faults in a Diesel Generator

by Starlight Generator dieselgeneratortech

Diesel Generator “Fail to start” is a very broad description of the problem. In general, the troubleshooting sequence is as follows.

Does it crank? Obviously it won’t start if the starter can’t turn it over.
Does it crank fast enough? Diesels need to achieve a minimum rpm before they will generate enough power to overcome friction. Many engines have “de-compression” systems which change the valve timing to assist the starter to get the engine going fast enough. In general, if in good condition, they should start and run at idle with the decompression lever engaged. A turbocharged engine automatically starts with reduced compression.
Assuming 1 and 2 don’t solve it, then possibly the engine is too cold. If cranking with decent battery power doesn’t start it, try using a block heater to warm it up. I’ve used water jacket heaters, oil dipstick heaters, and propane radiant heaters under the oil pan. All work better with a canvas tent over the engine.
If that still fails, then likely the engine is not getting fuel injected. Is fuel getting to the injector pump, particularly if the pump is fed by an electric low-pressure pump inside the fuel tank? If the injection pump has not been worked on in a way that could upset its timing, then likely there is no fuel getting to the injection pump. Very common if the engine last stopped because it ran out of fuel. You may need to bleed the fuel supply line using the bleed plug usually on the side of the injector pump. Open the line and drain fuel until no bubbles come out (you may need to run the electric fuel supply pump in the fuel tank to do this if the fuel is not gravity fed). That done, then crank the engine until the air gets out of the injector high pressure lines, and the engine should start.
If all that fails, then there may be something seriously wrong with the engine (timing chain / belt failed? Injector pump failed? Engine shutoff lever management failed? Something serious inside like failed piston, valves, etc.?) You likely need a qualified mechanic to diagnose it at that point.

dav