Electric Fuel Pump

Nov. 01, 2005 By ORC STAFF

Installation Instructions

Information adapted from Holley Replacement Parts Division electric fuel pump instructions. Instructions have been tailored to the Samurai.

Pump Mounting Location

The best location for mounting the electric fuel pump is in the rear of the vehicle, near the fuel tank and in a position where it is gravity fed. It should not be mounted in a closed area such as the vehicle’s trunk. It should be mounted on a solid member, such as the chassis, in a vertical position with the motor on top.

Warning: The pump must be located so that it is clear throughout the entire range of movement between the vehicle's body and the chassis. The pump and its connecting hoses must not be subjected to low ground clearance where any flying debris can cause damage.

Mounting the pump

  • Select a mounting site as close as possible to the fuel supply and away from possible sources of heat.
  • Use the mounting bracket supplied in the kit as a template and drill two clearance holes for a 5/16" bolt
  • Place the rubber gasket between the mounting bracket and motor housing and mount the pump in the vertical position (motor on top) using two 5/16" bolts.
  • Connect fuel line from the fuel tank to the fuel filter and from the filter to the inlet of the pump. Connect the carburetor delivery line to the outlet port of the pump. Use the same size line as original equipment.
  • Remove the mechanical pump and install a block-off plate. The ‘91 and up Samurais have a block-off plate installed from the factory. You can make your own from sheet metal.
  • Using the bracket supplied with the regulator, position the regulator as close to the carburetor as possible, taking care to minimize the exposure to hot surfaces. Do not mount the regulator on the exhaust manifold or any extremely hot surface.
  • The regulator is provided with two outlet ports: one port for the carburetor and one for a fuel pressure gauge. Connect one line from the regulator to one port on the Weber carburetor. Route the other carburetor port to the fuel return line back to the fuel tank.
  • The regulator is pre-set to 6 psi. However, for individual requirements, it may be readjusted to ½ psi for off-road use. The pressure is increased by loosening the regulator lock nut and turning the screw clock-wise.
Caution: Turning the regulator screw all the way in will result in excessive pressure and cause flooding of the carburetor. Always use a gauge when resetting the regulator.

Oil pressure switch installation

  • Disconnect the ground cable from the battery.
  • Remove the original equipment oil pressure switch from the left side of the block, and retain.
  • Screw a 1/8 inch pipe nipple into the block from which the pressure switch was removed. Use a suitable thread sealant on all fittings, taking care not to use to much which can contaminate the engine.
  • Screw a 1/8 inch pipe tee onto the nipple and position it in a manner to facilitate the installation of the original oil pressure switch and the new fuel pressure pressure switch in the remaining two holes.
  • Screw in the two switches and re-connect the lead to the oil pressure switch.

Note:The fuel pressure switch (Holley part number 12-810) will normally have three terminals marked C (common),  NC (normally closed) and NO (normally open).

  • Connect one lead of the fuel pump to ground and the other lead to the terminal marked “C” on the fuel pressure switch. Add a 7.5 amp in-line fuse holder using 14 gauge wire.
  • Connect the terminal marked “NO” to the terminal of the ignition switch that is on when the key is in the “ON” position
  • Connect the terminal marked “NC” to the starter motor circuit that is switched on when you turn the key to start.
  • To complete the installation, connect the ground cable to the battery.
Wiring diagram for fuel pump oil pressure switch

The fuel pump will run on the starter circuit as the engine is being cranked. As the engine oil pressure opens the fuel pressure switch the pump will run on the ignition switch circuit as long as the engine has oil pressure.

--Larry Harris


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