The Difference Between Fuel Sending Units & Fuel Pumps
by Richard Rowe
Fuel systems are fairly simple as a whole; a pump send fuel through the lines, which feed the carburetor or fuel injectors. However, in the midst of that simplicity lay a number of different components that make it all happen. It all starts with an understanding of some fuel system basics.
Fuel Pump
Fuel pumps come in two basic varieties: in-tank and in-line. Most fuel-injected cars use a high-pressure in-tank fuel pump that pushes fuel through the lines from inside the tank. In-line pumps sit outside the tank but near it and usually below it, and provide a low-pressure flow of fuel to keep the carburetor's reservoir full.
Fuel Sending Unit
A fuel sending unit doesn't "send fuel" as its name implies; it sends an electrical signal from the fuel level sensor to the fuel gauge. Only cars that use electronic fuel gauges or fuel injection computers utilize a fuel sending unit.
References
- "Auto Fundamantals"; Martin Stockel; 2005
- AA1 Car Library: Fuel Injector Troubleshooting
Writer Bio
Richard Rowe has been writing professionally since 2007, specializing in automotive topics. He has worked as a tractor-trailer driver and mechanic, a rigger at a fire engine factory and as a race-car driver and builder. Rowe studied engineering, philosophy and American literature at Central Florida Community College.
