Replacing Fuel Pump In '99 Chevy S-10: Step-By-Step Guide

The fuel pump is an essential part of a vehicle's fuel system, delivering fuel from the tank to the engine. If your fuel pump is not working properly, your engine may not start or run poorly. This step-by-step guide will show you how to change the fuel pump on a 1999 Chevy S-10.

Disconnect the negative battery cable

Disconnecting the negative battery cable is an important step when changing the fuel pump on a 1999 Chevy S-10. This is because it cuts power to the vehicle, making it safe to work on.

To begin, locate the negative battery cable. It is black in colour and usually clearly marked. Once you have identified the cable, proceed to carefully disconnect it from the battery. Ensure that you have a safe and accessible place to put the disconnected cable, away from any metal surfaces that could cause a short circuit.

After disconnecting the negative battery cable, it is important to take precautions to prevent accidental reconnection. You can do this by covering the battery terminal with electrical tape or a non-conductive cap. Additionally, ensure that you do not leave any metallic tools or objects nearby that could potentially cause a short circuit.

It is also worth noting that modern vehicles have multiple batteries and complex electrical systems. Therefore, it is crucial to consult the specific make and model's repair manual to identify all the battery locations and any special procedures required to safely disconnect the power.

Once you have completed this step, you can continue with the next steps of raising the rear of the truck, draining the fuel tank, and proceeding with the fuel pump replacement as outlined in other sections of the repair guide. Remember to exercise caution when working on your vehicle and refer to a qualified mechanic if you have any doubts or concerns.

Drain the fuel tank

To drain the fuel tank of a 1999 Chevy S-10, you will need to siphon out the fuel into approved containers for storage during the repair. This is an important step, as attempting to disconnect the fuel lines without discharging the system first can lead to a fuel spill.

If your Chevy S-10 has over a quarter of a tank of fuel, it will be incredibly heavy, so it is important to drain the tank before attempting to remove it. This will make the process much safer and easier.

To drain the tank, you can use a hand siphon pump or a siphon if your fuel tank has gas. Be sure to collect the drained fuel in approved containers, as gasoline is highly flammable and poses a serious safety risk if not handled properly.

Once the tank is drained, you can proceed to the next steps of lowering the tank and replacing the fuel pump. Remember to always replace the fuel filter when replacing the fuel pump.

Remove the fuel tank

To remove the fuel tank from a 1999 Chevy S10, follow these steps:

Park your Chevy S10 on a level surface, ensuring you have enough space to work around the truck. Disconnect the negative battery cable and raise the rear of the truck with a jack. Secure the truck on jack stands.

Next, drain the fuel tank. If there is more than a quarter of a tank of fuel left, it will be very heavy, so use a siphon to drain the fuel into approved containers.

Disconnect the fuel filler neck, which is the tube from the gas cap to the fuel tank. Remove the tank shield or guard, which protects the fuel tank from road debris.

Now, use a ratchet and socket to remove the tank-holding straps. Lower the fuel tank just enough to access and disconnect the electrical wires and fuel lines. Be prepared for a small amount of fuel to come from the lines, even after discharging the fuel system.

Finally, lower the tank to the ground.

At this point, you can access the fuel pump for removal and replacement.

Remove the fuel pump from the fuel sending unit

To remove the fuel pump from the fuel sending unit of a 1999 Chevy S-10, you will need to first park your truck on a level surface with enough room to work around it. Next, disconnect the fuel pump relay in the engine compartment. This is located in the fuse/relay box for 1995 to 1997 2.2L engine models. For other models, you will need to press the small stem inside the Schrader valve, which is located on the fuel inline rail, right before the first fuel injector. Cover the valve with a shop rag as you do this to catch any fuel.

Now, disconnect the negative battery cable and raise the rear of the truck with a floor jack, supporting it on two jack stands. Drain the fuel tank into an approved container through the filler pipe. You may need to use a hand siphon pump to do this.

Disconnect the clamp from the filler hose at the tank with a screwdriver and remove the hose. Remove the tank shield. Support the fuel tank with a floor jack and a piece of wood on the jack pad to avoid damaging the tank.

Remove the tank-holding straps with a ratchet and socket. Lower the fuel tank so you can disconnect the fuel lines from the fuel pump/sending unit assembly on top of the tank. Unplug the pump electrical connector and lower the tank to the floor.

Now, you can remove the fuel pump from the fuel sending unit. To do this, turn the lock-ring tabs holding the pump/sending unit assembly to the tank counterclockwise with a drift punch and a soft hammer until the ring is released. Lift the pump/sending unit assembly off the tank and remove the pump.

Install a new pump

Now that you have accessed the fuel pump, you can install a new pump.

Firstly, ensure that the new pump has a new O-ring around the top to create an airtight seal once installed. Place the new pump into the pump/sending unit assembly, and discard the old pump/sending unit O-ring seal. You can then install a new sending unit O-ring and set the pump assembly back into the tank.

Lock the assembly lock ring by turning the ring clockwise until it locks into place. Reconnect the fuel and electrical connections. You may need to raise the tank back up onto the stands or jack that you used to help lower the tank. Ensure these connections are clean, dry, and tight.

Position the tank back into its original position and place the holding straps back into place, tightening them down. Pay attention to the electrical connections and fuel lines during this time to ensure they are not being smashed or crushed. Replace the skid plate or tank guard that protects your fuel tank from road debris.

Remove all tools and trash from below the vehicle and lower it to the ground. Restore power by plugging in the fuel pump relay and reconnecting the negative battery cable. Finally, turn the vehicle on. If it starts and runs as normal, the pump is working. If the vehicle does not start, there is an issue.

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