Fuel Pump: Testing and Inspection
Fuel Supply Components:
FUEL PUMP ELECTRICAL CHECK
1. Turn ignition "ON" and listen for fuel pump.
^ Fuel pump should run for approx. 5 seconds when ignition is turned "ON" (should be audible, but you may need a second person under the car with a hand on the pump to tell if it's operating).
If OK, go to FUEL PUMP PRESSURE AND CHECK VALVE TEST (below).
If not OK, check fuel pump relay and fuse #13 (see FUEL PUMP RELAY in this section).
Fuel Pump Relay Socket Terminal ID:
2. Remove fuel pump relay and connect jumper wire between relay panel terminals #48 and #52.
^ Fuel pump should run (should be audible, but you may need a second person under the car with a hand on the pump to tell if it's operating).
If not, disconnect electrical connections at the pump and repeat step 3 while monitoring voltage at the pump connectors.
^ Should have battery voltage while jumper wire is connected. If voltage is OK and pump does not run, replace pump. If no voltage is present, check for open or short to ground in wiring between fuel pump relay terminal #52 and fuse #13, or between fuse #13 and fuel pump (see CHASSIS ELECTRICAL DIAGRAMS).
FUEL PUMP PRESSURE AND CHECK VALVE TEST
Checking Fuel Pump Pressure And Check Valve:
1. Disconnect fuel inlet hose from fuel distributor and connect to fuel pressure gauge as shown in illustration (shut-off valve in closed position).
2. Operate fuel pump until gauge pressure reading is approx. 73 psi (5 bar), then turn pump "OFF". (Operate pump by bridging terminals of fuel pump relay socket as in step 2 of electrical test above.)
NOTE: If pressure excedes the specified value, bleed off excess pressure by carefully opening shut-off valve on gauge. Cover with clean rag to avoid spraying fuel.
If after one minute of pump operation the specified pressure is not reached, check for plugged fuel filter or kinked/pinched fuel supply line. If filter and line are OK, replace fuel pump.
3. Wait 10 minutes then observe residual pressure on gauge.
^ Should be 49 psi (3.4 bar) minimum.
If less than specified and there are no leaks, replace fuel pump check valve.
FUEL PUMP VOLUME TEST
1. Reconnect fuel supply line to fuel distributor (line must be connected because this test checks for adequate volume under normal pressure).
Checking Pump Volume From Fuel Return Line:
2. Disconnect fuel return line at connector next to fuel distributor (see illustration), and direct outlet from fuel distributor into suitable measuring container. You may need to add an extra piece of hose to do this safely.
3. Remove fuel filler cap.
4. Connect voltmeter between electrical terminals of fuel pump.
5. Energize fuel pump for 30 seconds (see step 2 of electrical test above) and note operating voltage at the pump.
Fuel Pump Volume Vs. Supply Voltage:
6. Check volume of fuel in container after 30 seconds of operation and compare with chart.
^ If volume is less than that specified for the noted operating voltage, check for restricted or plugged fuel filter and/or supply line. If filter and line are OK, replace fuel pump.