Replace The Fuel Pump on a 1999 Chevy S10

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Fuel pumps can fail for a large number of reasons. Regardless, they are relatively easy to change once you have access to them. This can be the hard part. Generally speaking, you either have to lift the bed of the truck off of the frame, or you need to drop the tank. Working on a truck like the Chevrolet S10 can be done either way. This is how you perform a fuel pump replacement by dropping the tank.

  • Ratcheting Socket Wrench
  • Socket Set
  • Siphon (if your fuel tank has gas)
  • Flathead Screwdriver
  • Jack and Jack Stands
  • Replacement Fuel Pump

Always replace the fuel filter when replacing the fuel pump.

Discharge the Fuel System


Unplug the fuel pump relay: This will keep the vehicle from sending power to the fuel pump. It is located in the main fuse box under the hood.


Attempt to start the vehicle: This will force the engine to pull any fuel from the fuel lines leaving them empty. It also ensures that your fuel pump has been disconnected from the electrical system, making it safe to disconnect.

Do not skip this step! Fuel lines are pressurized. There will be a fuel spill if you attempt to disconnect a line without discharging the system before hand.

Prepare to Drop Fuel Tank


Disconnect the negative battery cable: This will cut power to the vehicle and make it safe to work on.


Drain fuel tank: If the tank has over 1/4 tank left, it will be incredibly heavy. You will want to siphon out any fuel into approved containers for storage during the repair.


Raise Vehicle: If you do not have enough room under the truck, lift the vehicle and secure it on jack stands.

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Drop the Fuel Tank


Disconnect the fuel filler neck: This is the tube from your gas cap to your fuel tank. It needs to be disconnected so that your fuel tank can be removed.


Remove the tank guard or skip plate that covers the fuel tank.


Support your fuel tank: Use a jack or jack stand to support the tank as it is being lowered. The best jacks or stands to use are adjustable so you can lower the tank with the stand. Otherwise, you will need help to lower the tank once it has been removed.

If using a jack stand to support the tank, make sure you use wood or another type of buffer to keep from harming the exterior of the tank.


Use ratchet to remove holding straps: The tank is held into place with two holding straps that wrap around it. You will need a socket and a ratcheting wrench to remove the bolt holding the straps in place.


Lower tank enough to remove electrical wires and fuel lines: Lower the tank just enough to access the electrical wires and fuel lines. Disconnect all electrical connections and fuel lines. You can then lower the tank to ground.

Even after discharging the fuel system, disconnecting the lines will be accompanied by a small amount of fuel coming from the lines. Be prepared as you disconnect them.

Remove and Replace Fuel Pump


Remove old fuel pump: Release the locking tabs by turning the retaining lock ring which holds the pump in place. You can then lift the pump assembly from the tank.

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Install new pump: Replace the old pump with the new one, and secure the new pump into place by turning the locking ring. Make sure the new pump has a new O-ring around the top to make an airtight seal once installed.


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.


Raise the tank: Position the tank back into its position. Place the holding straps back into place and tighten them down. Pay attention to the electrical connections and fuel lines during this time to ensure they are not being smashed or crushed.

Prepare for Testing


Replace tank guard: Replace the skid plate or tank guard that protects your fuel tank from road debris.


Lower vehicle: Remove all tools and trash from below the vehicle and lower it to the ground.


Restore power: Plug in the fuel pump relay and reconnect the negative battery cable restoring power to the vehicle and fuel pump.

Test and Inspect


Test: Turn the vehicle on. If it starts and runs per usual, the pump is working. If the vehicle does not start, there is an issue.


Inspect: Inspect the area of repair for any leaks.

Fuel pumps and their modules can fail for many reasons. Replacing a fuel pump is easy if you follow the proper safety measures and only attempt to lower the tank when it is close to empty.

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