Instructions on How to Replace a 1994 S10 Fuel Pump

The Chevrolet S10, like many other pickup trucks, has its fuel pump installed within the fuel tank. The fuel pump is contained within a module, but the 1994 S10 is one of the last models where you can replace the pump individually instead of having to replace the entire module. You still need to disconnect the tank from the truck to service the fuel pump.

Things You'll Need

• Siphon pump
• Gas can
• Open-ended wrenches
• Socket wrench set
• Shop rags
• Floor jack
• 2 jack stands
• 12X12 inch plywood piece
• Hex screwdriver
• Brass punch or wood dowel
• Flat-bladed screwdriver
• Cleaning solvent
• Compressed air
• Spray penetrating oil

Instructions

Removing the Fuel Tank

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

2. Drain the fuel tank of as much fuel as possible using a siphon pump or vacuum pump and deposit the fuel into a gasoline can.

3. Relieve the fuel system's pressure--open the fuel filler cap on the side of the truck, then loosen the fuel line outlet fitting for the fuel filter using a wrench wrapped in a shop rag--fuel will come out and absorb into the rag. The filter is mounted to the frame near the fuel tank.

4. Raise the truck's rear end with a floor jack (use the differential as a lifting point) and support it on two jack stands under the frame in front of the truck's rear axle. Unbolt the fuel tank shield with the appropriate wrench and remove it.

5. Raise a floor jack underneath the tank to support it--place a piece of wood on the jack head to protect the tank--then unbolt the tank's support straps with the appropriate wrench. Lower the jack and tank enough to disconnect the electrical connectors from the top of the tank.

6. Disconnect the fuel and vapor lines from the top of the tank by loosening their clamps with a hex-nut driver. Disconnect the vapor lines from the tank rollover valve using two open-end wrenches--one to unscrew the tube fitting while the other holds the stationary fitting in place. Lower the jack and pull the tank out from under the truck.

Changing the Fuel Pump

1. With the tank on the ground, tap the locking ring for the fuel pump module in a counterclockwise direction--use a wooden dowel, brass punch or or other rod that won't cause sparks--until the tabs in the ring line up with the recesses on the tank's surface.

2. Remove the lock ring and lift the fuel pump assembly out of the tank; pull it out at an angle to make sure you don't damage the float or the filter.

3. Disconnect the small, bag-like strainer from the pump's bottom end--pry it off at the collar with a flat screwdriver. Lift the tab on the electrical connector with a screwdriver to disconnect the connector and remove the fuel pump from the bracket.

4. Install the replacement fuel pump within the bracket and connect the electrical connector and replace the strainer.

5. Install the pump assembly within the tank, replace the lock ring and tap it with the dowel or punch to lock it in place.

6. Raise the tank in place on the truck using the jack, raising it just enough to reconnect the wiring and the fuel/vapor lines with the clamps or wrenches. Raise the tank the rest of the way, strap the tank in place using the strap bolts and bolt the tank shield in place.

7. Lower the truck off the jack and reconnect the battery cable.

Tips & Warnings

• If the strainer is dirty, clean it with a good solvent and blow it dry with compressed air before re-connecting it. Replace the strainer if it is too dirty to clean.

• You may have trouble with rusted bolts on the tank shield or straps. If necessary, soak them with spray penetrating oil and let them set awhile.

References

• "Chilton General Motors S-Series Pick-ups Repair Manual"; Robert Maddox; Haynes North America; 2004