How to Replace the Fuel Pump on a 1988 Chevrolet Blazer S10

The fuel pump on a Chevrolet S10 Blazer, like most pickup trucks, is installed within a module inside the fuel tank, requiring you to remove the tank from the vehicle in order to service it. The 1988 S10 Blazer is one of the models where you can remove and replace the pump from its module after removing it from the tank. The fuel system is under extreme pressure, and relieving this pressure is not as easy as with later models, so use extreme caution.

Tools Used: Siphon pump, Gas can, Fuel pressure gauge, Floor jack, Jack stands, Wrench, Pliers, Tags, Screwdriver, Wood plank or block, Hammer and brass punch, O-ring

Replace the Fuel Pump

Removing the Fuel Tank

Drain the fuel from the tank using a siphon pump inserted into the fuel tank via the filler door and neck on the side of the truck. Deposit the fuel into a gas can.

Disconnect the truck's negative battery cable from inside the engine compartment.

Relieve the fuel pressure--open the filler cap on the side and then connect a pressure gauge to the pressure fitting on the inlet fuel pipe fitting. Place the gauge's bleed hose in your gas can and open the gauges release valve to bleed out the pressure.

Raise the truck's rear end and support it with jack stands.

Disconnect the filler hose from the fuel tank--loosen its hose clamp with pliers.

Tag each of the wires and hoses connected to the top of the fuel tank and then disconnect them--if they have quick-connect fittings, squeeze the tabs at the end either by hand or with a small, flat screwdriver.

Support the tank with either an assistant's help or by raising a floor jack with a block of wood underneath the tank, then remove the tank's support straps--remove their bolts with a wrench.

Lower the tank slowly and disconnect any other wires or hoses that were not accessible while the tank was in position.

Replacing the Pump

Tap the locking ring holding the fuel pump module in place with a brass punch and hammer to free it from the locking tabs, then twist the ring off.

Lift the module with the fuel pump and fuel sending unit out of the tank.

Pull the fuel pump up into the mounting tube as you pull away from the bottom support. Once the pump clears the bottom support, pull the pump out of the rubber connector to disconnect it from the sending unit.

Push the replacement fuel pump onto the sending tube to connect it to the sending unit.

Lower the fuel pump module back into the fuel tank; install a new O-ring on the tank's groove where the module contacts the tank, and make sure you don't twist or fold the module's fuel strainer.

Twist the locking ring in place on the module and turn or drive it clockwise--using the brass punch and hammer--so it is in position over the tabs on the fuel tank.

Install the fuel tank back onto the truck--connect the lines and wires, using the tags to guide you, raise the tank with your jack or assistant, bolt the straps in place and connect the filler hose to the tank with its clamp.

Lower the car off of the jack stands, reconnect the battery cable and add fuel back into the tank.

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