Engine Basics & Components
This component, found in diesel engines but not modern gasoline engines, sprays finely atomized fuel directly into the combustion chamber.
What is a fuel injector?
Diesel engines generally have a much higher ratio of this measurement compared to gasoline engines, often ranging from 15:1 to 22:1.
What is the compression ratio?
This clear, yellowish fluid is injected into the exhaust system of modern diesel trucks to break down dangerous NOx emissions
What is Diesel Exhaust Fluid (DEF) or AdBlue?
This precise hand tool is used to tighten engine bolts, like cylinder head bolts, to an exact measurement specified by the manufacturer.
What is a torque wrench?
Unlike gasoline engines that use spark plugs, diesel engines rely on this physical property to ignite the fuel-air mixture.
What is compression (or heat of compression)?
This forced-induction device uses exhaust gases to spin a turbine, forcing more air into the combustion chamber to increase power.
What is a turbocharger?
This exhaust component traps physical soot particles created during diesel combustion to prevent black smoke.
What is a Diesel Particulate Filter (DPF)?
Technicians plug an electronic scan tool into this standardized vehicle port to read engine fault codes and live data.
What is the OBD-II port (or Diagnostic Link Connector/DLC)?
This heavy component at the bottom of the engine stores rotational energy to help keep the crankshaft turning smoothly between power strokes.
What is a flywheel?
This component cools the compressed air coming from a turbocharger before it enters the engine, making the air denser.
What is an intercooler (or charge air cooler)?
This system reroutes a portion of an engine's exhaust gas back into the engine cylinders to lower combustion temperatures and reduce NOx.
What is Exhaust Gas Recirculation (EGR)?
Because diesel fuel systems operate under extreme pressures, technicians use this specific gauge tool to safely check pressure in the fuel rail.
What is a high-pressure fuel pressure gauge (or electronic pressure tester)?
hese electrical heating devices are used in diesel engines to warm up the combustion chambers before starting a cold engine.
What are glow plugs?
This modern high-pressure fuel system utilizes a single shared pressurized line to feed all the injectors at extremely high pressure
What is a Common Rail Fuel Injection system?
If a diesel engine is blowing thick white smoke from the exhaust, it usually indicates this unburned substance is present, or there is a coolant leak.
What is raw/unburned fuel?
This hand tool, which uses thin metal strips of varying thicknesses, is essential for measuring and adjusting valve clearance (lash) on a diesel cylinder head.
What is a feeler gauge?
This is the specific term for the four individual strokes in a standard four-stroke diesel cycle, in the correct operational order.
What are Intake, Compression, Power (or Combustion), and Exhaust?
This thermodynamic cycle is the theoretical basis for the operation of the diesel engine, distinct from the Otto cycle
What is the Diesel Cycle?
This dangerous condition occurs when a diesel engine draws in an external fuel source (like engine oil or vapor) and accelerates uncontrollably until it destroys itself.
What is a diesel engine runaway?
To diagnose a cylinder that is misfiring or lacking power, technicians use this specific test to measure how much compressed air is escaping from the combustion chamber.
What is a cylinder leakage test (or leak-down test)?