DESCRIPTION & OPERATION
Two types of fuel pumps are used, a high pressure pump and a low pressure pump. The high pressure pump has a relief valve to prevent excessive pressure. When relief valve opens, fuel flows from high pressure side to low pressure side.
On the low pressure pump, if fuel flow has excessive pressure a relief valve will open and by-pass fuel flow into inlet port. The electric fuel pump is located at the left side of the vehicle or inside fuel tank on left corner. Fuel pump is a sealed unit and is serviceable as an assembly. A solid state relay senses negative pulsations at the ignition coil and switches the pump on when the engine is running or the starter is engaged. Relay is located under dash panel at the left side of driver's compartment. Circuit is protected by a fuse in the fuse box as well an in-line fuse.
Low Pressure Pump
- Remove fuse box panel mounting bolt and nut. Pull down panel and remove fuel pump cut-off relay. Turn ignition switch to "ON" position.
- Connect positive probe of voltmeter to Black/Yellow wire terminal of fuel pump cut-off relay connector. If no voltage, check fuse and continuity of Black/Yellow wire.
- If voltage is present, check Blue wire at cut-off relay for battery voltage. If Blue wire does not show battery voltage, check for continuity between connector and negative side of coil.
- Turn ignition switch to "OFF" position. Attach jumper wire between the 2 Black/Yellow wires of connector. Turn ignition switch to "ON" position.
- If fuel pressure is now available and battery voltage was present at Blue wire, replace the cut-off relay. If no pressure is available, unplug fuel pump leads at pump.
- Attach positive lead of voltmeter to the Black/Yellow wire and negative lead to Black wire. Battery voltage should be present with ignition on. If not, check continuity of Black/Yellow wire from relay and Black wire to ground.
High Pressure Pump
- Relieve fuel pressure. Remove fuel filter bolt while holding banjo bolt with another wrench. Connect a fuel pressure gauge. Start engine. With engine idling and vacuum hose of pressure regulator disconnected, measure fuel pressure.
- Fuel pressure should be 33-39 psi (2.35-2.75 kg/cm 2 ). If pressure is higher than specification, check for pinched or clogged fuel return hoses or pipes, bad pressure regulator.
- If pressure is lower than specification, check fuel filter, pinched or clogged fuel hose from fuel tank, bad pressure regulator, fuel line leaking, pinched, broken or disconnected regulator vacuum hose.
- Turn ignition switch to "OFF" position. Disconnect connector from relay from behind fuse box. Attach jumper wire between 2 Black/Yellow wires in fuel pump cut-off relay connector.
- Relieve fuel pressure. Disconnect fuel return hose from regulator. Hold measuring cup under fuel hose from regulator. Turn ignition switch to "ON" position for 10 seconds.
- Measure amount of fuel flow. Flow amount should be 7.8 ounces (230 cc). If fuel flow is less than specification, check fuel filter, clogged fuel line, bad pressure regulator.
High Pressure Pump Regulator
- Check for pinched or broken vacuum hoses. Connect fuel pressure gauge to service port of fuel filter. Start engine. Check that fuel pressure increases when vacuum hose from regulator is disconnected.
- Fuel pressure should be 33-39 psi (2.35-2.75 kg/cm 2 ). If fuel pressure does not increase, pinch return hose slightly 2 or 3 times. If fuel pressure still does not increase, replace pressure regulator.
Low Pressure Pump Regulator
- Check pressure regulator vacuum lines and hoses for proper connection, cracks, blockage. Disconnect No. 1 vacuum hose from pressure regulator. Connect a vacuum gauge to hose.
- Start engine. Allow engine to idle. Check for vacuum. Vacuum should be present. If no vacuum is present, check vacuum port, vacuum lines and hoses. If vacuum port, lines and hoses are all good, replace solenoid valve.
- Stop engine, then restart engine. Check for vacuum again. No vacuum should be present. If vacuum is present, replace solenoid valve. Stop engine. Connect fuel pressure gauge to service port of fuel filter.
- Start engine. Check that fuel pressure increases when No. 1 vacuum hose is disconnected from regulator. Fuel pressure should be 36-41 psi (2.55-2.85 kg/cm 2 ).
- If fuel pressure does not increase to specification, lightly pinch return hose. If pressure still does not increase, replace pressure regulator.
Removal & Installation
- Raise and support vehicle. Remove left rear wheel. Unplug electrical leads at fuel pump and clamp fuel lines between pump and tank.
- Remove fuel pump cover bolts. Lift off cover and pump as an assembly. Disassemble pump from cover. To install, reverse removal procedure.
- Relieve fuel pressure. Remove fuel pump access cover located inside of luggage area. Disconnect fuel lines and coupler. Remove fuel pump mounting nuts.
- Remove fuel pump from fuel tank through access hole. If fuel pump is hard to remove from tank, loosen fuel tank mounting nuts and slightly lower fuel tank. To install, reverse removal procedure.
