How to Replace a Fuel Sending Unit on a 2001 Z24 Cavalier

Better late than never, the Z24 trim level of the Chevrolet Cavalier hit showrooms in 1986, a year after its anticipated release, featuring a sports appearance package and a 125-horsepower, 2.8-liter V-6 engine. The 2001 Z24 Cavaliers engine had 0.4 liters and two cylinders fewer than the models original V-6 engine but cranked out 25 horsepower more than the original. The 2001 model's 2.4-liter engine requires between 53 and 59 psi of fuel pressure to run correctly, and the fuel sending unit is what creates the required pressure. Replacing the fuel sending unit is an in-depth task, but doing the job yourself will save a lot of money in labor charges.

Instructions

Open the gas cap and insert a semi-rigid fuel siphon into the fuel filler tube. When you feel it hit resistance, lightly push through it; this is the fuel tank flapper door, and it requires a little effort to open. Continue feeding the siphon through the filler tube until you feel it contact the bottom of the fuel tank.

Put the siphons drain hose in a 5-gallon fuel can and begin siphoning fuel from the tank. When the fuel can becomes full, stop siphoning, remove the drain hose from the can, seal the can and place the siphon hose in an empty can.

Remove the siphon once you cannot siphon out any more fuel. You aren't likely to siphon out all of the fuel, but as long as the fuel tank is a quarter full or less, you can safely remove it. Place all of the gas cans in a safe location.

Raise the rear of the Cavalier with a floor jack and slide jack stands under its rear suspension crossmember. Lower the vehicle onto the jack stands. Find the wiring harness protruding from between the top of the fuel tank and the vehicles floorboards; this is the fuel pump wiring harness.

Unplug the fuel pump wiring harness. Start the engine and allow it to idle until the engine stalls. This bleeds all of the pressure from the fuel lines.

Attach a memory saver to the vehicle, in accordance with the memory savers instruction manual. This will prevent the loss of important driveability data, as well as radio presets and clock settings. Disconnect the negative battery cable from the battery, using a combination wrench, and position it aside to prevent inadvertent reconnection.

Disconnect the fuel line, plugged into the fuel tank side of the fuel filter, by pressing the line toward the filter, squeezing the plastic tabs on the connector, and pulling the hose and connector away from the fuel filter.

Find the fuel return line, the hard line running from the engine to the fuel tank, whose quick-connect fitting is accessible with the tank installed. Disconnect the fuel return line from the tank by squeezing the tabs on the quick connect fitting and pulling the line from the fuel tank.

Trace the exhaust system from back to front, pressing the metal exhaust mounts from their rubber hangers as you encounter them. Allow the exhaust system to rest on the rear axle beam.

Remove the bolt and nuts securing the exhaust heat shield to the underside of the vehicle, using a ratchet and socket, and remove the heat shield.

Loosen the hose clamp securing the fuel filler hose to the fuel tank, using a flat-head screwdriver, and disconnect the fuel filler hose from the tank.

Pull the evaporative emissions vapor hose, the rubber vacuumlike hose, from the EVAP canister with a slight twisting motion.

Unplug the rear wiring harness from the multiway rear body connector and pull the wiring harness from the fuel tank strap. Position the wiring harness out of the way to avoid damaging it.

Set a 6-inch-long piece of 2- by 4-inch wood on the jacking plate of a floor jack. Raise the jack until the wood contacts the fuel tank, but do not apply any upward pressure on the tank. Remove the bolts securing the fuel tank straps to the body, using a ratchet and socket.

Instruct an assistant to carefully lower the fuel tank as you hold it steady on the floor jack until you can access the fuel tank pressure sensor wiring harness. Unplug the wiring harness.

Remove the fuel tank from the jack and place it on a flat surface. Press downward on and rotate the fuel senders retaining ring clockwise, using a fuel sender lock nut wrench GM tool No. J-39765 to remove the ring.

Lift the fuel sender assembly from the fuel tank carefully and pull the old fuel sender seal from the tank.

Install a new fuel sender seal on the tank and lower the fuel sender assembly into the tank. While lowering the sender assembly, line up the senders pipes with their respective markings on the fuel tank.

Press downward on the sender assembly lightly until it is flush with the top of the hole it sits in. Tighten the retaining ring, using a fuel sender lock nut wrench.

Balance the fuel tank on the floor jack with the block of wood and instruct your assistant to guide the jack and tank under the vehicle until the tank aligns with its bed in the floorboards. Tell your assistant to slowly raise the jack until you can reconnect the fuel tank pressure sensor wiring harness. Connect the harness.

Instruct your assistant to raise the jack until the fuel tank is in its correct position; do not apply any upward pressure to the tank once it is in position. Install the fuel tank straps and torque their retaining bolts to 26 foot-pounds, using a torque wrench and socket.

Reconnect the rear wiring harness into the multiway connector and press the harness into its bracket on the fuel tank strap.

Press the EVAP vapor hose back into its receptacle on the EVAP canister. Plug the filler hose back into the tank and tighten its hose clamp to 27 inch-pounds, using an inch-pound torque wrench and socket.

Reinstall the exhaust heat shield; tighten its bolt to 18 inch-pounds and its nuts to 9 inch-pounds. Lift the exhaust into place and press the metal exhaust mounts into their respective rubber hangers.

Press the fuel return pipe into the return line on the fuel tank and listen for the quick connector to snap into place. Press the fuel filter pipe on the fuel tank into the fuel filter until you hear the quick connector snap into place. Plug the fuel pump wiring harness into the vehicles wiring harness.

Raise the Cavalier off the jack stands and remove the jack stands. Lower the vehicle to the ground.

Tighten the fuel filler cap. Install the negative battery cable and hand-thread its retaining bolt. Tighten the bolt to 12 foot-pounds. Disconnect the memory saver.

Turn the ignition to the On position for two seconds, then turn it to the Off position for 10 seconds. Turn the ignition back to the On position and check for any fuel leaks. If there are no leaks, start the vehicle and verify that it starts and idles correctly.