Diesel won't start?
As always, read your manual
first. If you're here trying to brush up on the most likely reasons that you may
experience a "No start" situation, you've come to the right spot. We have listed
the most common causes for a no start on a diesel engine, in order of most probable
occurrence. This isn't to say that you may not have the most improbable source of a
failure, but often the basics are the best place to start. First, we'll list the things to
look for and then we'll explain the ones that need explanation.
Warning: Diesel fuel is at extremely high pressure and extreme care should be taken when dealing with the injectors, injector pump, and associated components. A fuel injector will shoot diesel fuel into your body through your skin, given the right conditions. Read all warnings and safety precautions in your manual before attempting any test procedures on a diesel engine. Wear safety goggles when dealing with high pressure diesel fuel.
Note: There are two fuel pumps on most marine diesel engines. A low pressure primary fuel pump draws fuel from the fuel tank and a high pressure fuel injector pump pressurizes the fuel lines to the injectors. Both have to be working properly
|Note: In extremely cold weather,
diesel fuel can turn to jell and of course you are not going to be able to pump jelled
diesel fuel. Also note that diesel fuel will grow a fungus that will clog filters and
lines and care needs to be taken to prevent this fungus before it starts to grow in your
fuel system. There are numerous additives for diesel fuel that prevent and or reduce these
problems. (Ask any trucker)
Fuel Kill Circuit
Since the only practical way to stop a diesel engine is to "cut off"
the fuel supply, almost every diesel ever manufactured uses a fuel pressure relief valve
in the high pressure side of the fuel injection system.
| As you can tell from the list above, fuel
and related issues concerning the fuel are the number one items that can cause a no start.
Air in the fuel line can come from several sources.
The easiest way to check for air in your system is to carefully loosen an
injector line at the injector or the injector pump output and crank the engine,
observing the fuel flow. Bubbles and or no fuel drip while cranking is not a good sign.
Water in the fuel can come from several sources.
Remove the fuel filters and check for water in the
fuel by draining the filters into a clean clear used 2 liter soda
bottle. Let sit for awhile to see if the water settles to the bottom
of the bottle.
========== Work In Progress ============
Note: This article is primarily written for traditional diesel engines that have basic mechanical operation. Newer computer controller engines with electric fuel pumps and injectors will have similar problems with poor fuel quality however, if a computer controlled engine doesn't start... check fuel quality and if it's good... call a professional.
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