The main difference between ignition of a Diesel engine compared to that of an ordinary gasoline engine is that in the diesel engine, the heated and compressed air in the cylinder ignited the fuel, whereas in a gasoline engine, the use of a spark plug quickly ignites the fuel.  This means that the Diesel Fuel Injector pump must inject the fuel directly into the cylinder, towards the heated compressed air.  This is why the divice is so much difference then your traditional fuel injectors of say a Honda Civic.

If a Fuel pump gets clogged, your engine will luckily not start.  This is why it is important, not only to clean the pumps, but to also replace them in a timely fashion when the manufacturer time limit is up. Delphi, Airtech, Cav, Bosch, and Retech, are all reliable brands of fuel pumps. Most can be purchased online for a discount, and most the time easily installed.    There are 2 types of Duiesel Fuel Injection:

• Direct Fuel Injection: Direct injection injectors are mounted at the very top of the combustion chamber of the engine. This method can make the engine extremely noisey, however will save anywhere from 15-25% of the fuel compared to any other methods of injection
• Indirect Injection: This is just as it sounds.  Via this method, the fuel is ignited outside of the main injector chamber, and then is delivered there.   This will make the ignition process much more quiet, however, you will waste up to 10% more fuel.