Fuel is pumped from the gas tank up into the engine, and these handy little devices come in any number of shapes, sizes, and applications imaginable. Each of the three different key types of fuel pumps has a specific purpose: in-tank pumps, external electric pumps and mechanical pumps – and some are much more user-friendly to replace than others.
The simplest design is also the one that has been in use the longest: the mechanical fuel pump. There are only a few moving parts and these are most often used in concert with diesel engines and those that have carburetors instead of fuel injectors. Their power is provided by the crankshaft or camshaft and as the speed increase so does the volume of the fuel being pumped, giving the engine more to “drink” as needed.
Electric external fuel pumps, also known as inline fuel pumps, are most often located external to the gas tank inside of the vehicle frame and can be used in a number of ways. They may have an internal fuel pump that comes alongside to help them get the gas quickly during times when the engine needs an extra boost.
Electric internal fuel pumps float inside the gas tank, but they can be difficult to reach and replace, especially for the average driver. An internal fuel pump is surrounded by a “sock” that keeps the debris that could be floating in your gas tank from reaching the engine as the gas is being pumped through. Remaining particulates are caught by the fuel filter as gas continues on through the system.
Mechanical fuel pumps can be made in a variety of different fashions – so check your owner’s manual or consult a professional before making your purchase.
The empty float height and float retention should match the OEM (Original Equipment Manufacturer) specifications to guarantee that the gas gauge reading will be accurate.
You want to be sure that the part is validated, matched and tested to the right vehicle application before purchase.
A fuel pump is a critical part of your vehicle’s proper functioning. If you’re hearing sputtering when you try to start your car, suspect that it might not be getting gas to the engine and check your fuel pump.
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This article originally appeared on YourMechanic.com as How to Buy a Good Quality Fuel Pump and was authored by Valerie Johnston.