Chevy Fuel Pump - The Sum Of All Parts!

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Courtesy Street & Performance Sep 1, 2004 0 Comment(s)
Sucp_0409_01_z Chevy_fuel_pump Components 1/9

A.AC Delco EP-185 External Hi-Pressure Fuel Pump
B. AC Delco EP-12S Pusher Pump
C. AN Fittings for External Fuel Pump
D. AC Delco GF-481 Fuel Filter w/S&P 16mm to AN#6 Fittings and Mounting Bracket
E. External S&P Aluminum Mounting Bracket for a EP-185 Pump

You've heard the phrase that the sum of all parts is greater than the whole, well when it comes to fuel injection this adage is a motto to live by. All of the requisite components work together as a team. So when you are planning to build your machine, you need to plan a package that will work together before you even start to bolt it on. A little planning in the beginning stage will save you a lot of headaches during the building process and provide you with a vehicle that will be trouble free and a pleasure to drive.

One of the most important things in this plan is the fuel delivery system. Keep in mind that the easiest way is not always the best way. In the long run the easy way my cause you a lot of problems. Two of the first things to consider are the gas tank and the fuel pump. You want to put the pump in the tank if at all possible because external pumps are not designed to suck, but primarily to push.

Most people don't realize that external pumps that were used on Ford trucks, vans and 500ci engines had a low-pressure pusher pump in the tank that pushed fuel to the high-pressure external pump. A problem with external pumps, if they are not installed properly, is that you will not get the proper fuel pressure to the injection system, which, in turn, will eventually burn the pump up because of the lack of fuel to lubricate the pump. If you must use an external pump, a good pump to use is the '87-89 Ford Truck or Van, Mercedes, older Cadillac or Datsun 280ZX external pump. On these vehicles the tank had a good baffle inside. The pick-up port should be 1/2-inch NPT and close to the bottom of the tank. If the tank is not baffled fuel will run away from the pick-up port when going around a corner or accelerating.

Sucp_0409_02_z Chevy_fuel_pump Fuel_tank 2/9

Pictured above is a Stainless Steel Tank and mounting straps with a in-tank fuel pump provided by Rock Valley for a 55-56 Chevy.

If you pull out of the top of the tank, you should use an external pusher pump that is designed to suck fuel from the tank and push fuel to the high-pressure pump. You should also have a minimum of 3/8-inch line from the external pump to the pusher pump. Do not use a pre-filter with external pumps because as the filter gets dirty, it makes it more difficult for the pusher pump to push thru the filter. If using an external pump it needs to be mounted within 18 inches of the fuel tank. When installing new fuel line make sure that you flush the lines with fuel before connecting them to your injection unit. Blowing air through the lines will not remove some of the fine particles left in the lines from when they were cut. These particles will get trapped in the injector screens and stop the fuel flow through the injector.

If your external pump starts to make noise it is best to pick up a spare. External pumps are not the least expensive way to go. The Ford external pump is more than $400, and by the time you buy the fittings and other hardware you will have to spend as much as you would if you had a pump put in the tank. If you have a good tank, there are companies such as Rock Valley who you can send your tank to and they will install the pump. Additionally, Rock Valley, Tanks, No Limit, and other companies can provide a tank to fit your application with pumps already installed inside.

For later-model vehicles, it's even easier to put the pump in the tank. For instance, a fuel pump assembly out of a '86-87 Monte Carlo 4.3 throttle body will fit in '78 and later Monte and El Camino gas tanks. On '78-81 Corvettes all you have to do is use an '82 Corvette in-tank fuel pump assembly. On Blazers, Suburbans, and pickups you can use the same body style '87 and later gas tank or sending unit in earlier vehicles. If it is a throttle body-sending unit and you are running a TPI or multi-port, all you have to do is put a Corvette pump on the unit. For your application, you can call one of the Street & Performance tech staff for help (479/394-5711).