How to Replace the Fuel Pump on a 1988 GMC K2500

The GMC K2500 3/4-ton pickup uses a throttle body fuel injection system, where two fuel injectors are mounted in a housing that resembles a carburetor, and mounts on the intake manifold just like a carburetor.The fuel injection pump is mounted in the gas tank with the fuel sending unit.

Tools Used: Wrench set, Siphon pump, Gas can, Jack, Jack stands, Ratchet and socket set, Flat screwdriver, Brass drift punch, Rubber mallet, Fuel pump strainer, Replacement fuel pump

Replace the Fuel Pump

Park the K2500 on a level, paved surface. Shut off the engine and set the parking brake.

Remove the gas cap. Open the hood and use a ratchet and socket to disconnect the negative battery cable.

Use a siphon pump to siphon as much fuel from the fuel tank as possible. This will make it easier to handle the fuel tank when it is removed. Be sure to siphon fuel into an approved container. Raise the rear of the K2500 with a jack and support it with jack stands.

Use a flat screwdriver to loosen the hose clamps on the fuel filler hose and the vent hose. Disconnect the hoses. Place a floor jack under the fuel tank to hold it up when you loosen the mounting straps. Use the ratchet and socket to unbolt the two fuel tank retaining straps. Lower the tank just enough so that you can reach the top of the tank and disconnect the electrical connectors, ground strap and fuel lines from the fuel pump assembly. Be sure to note the arrangement to of the fuel lines so you can put them back in the proper place. Finish lowering the fuel tank to the ground and pull it out from under the K2500.

Use a brass drift punch and rubber mallet to carefully loosen the fuel pump assembly retaining ring by turning it counterclockwise. Remove the retaining ring from the fuel pump assembly.

Gently lift out the fuel pump assembly, being careful not to damage the fuel level sender. Remove the strainer from the end of the fuel pump. If the strainer is extremely dirty, replace it. Remove the fuel pump by pulling it up into the rubber connector far enough so that you can slide it out of its retaining bracket. Reverse the steps to install the new pump.

Tips & Warnings

The brass drift punch and rubber mallet are used to reduce the danger of sparking near the fuel tank.

Always work in a well-ventilated area, away from bare lightbulbs and other electrical devices.

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