Fuel Pump Circuit & Relay
- Turn ignition on. Attach jumper wire between test connector terminals F/P and GND in the diagnostic connector, next to battery. Listen for fuel pump operating sound. If there is no sound, check 10-amp ENGINE fuse, 30-amp FUEL INJ fuse, main relay, fuel pump relay and all electrical connections.
- Disconnect fuel pump connector. Check continuity between fuel pump battery positive and ground terminals. See FUEL PUMP CONNECTOR WIRE IDENTIFICATION table. If continuity exists, go to next step. If continuity does not exist, replace fuel pump.
- Measure voltage at fuel pump connector battery positive terminal. See FUEL PUMP CONNECTOR WIRE IDENTIFICATION table. If battery voltage exists, go to next step. If battery voltage does not exist, go to step 5).
- Measure resistance of fuel pump ground wire (Black wire) to chassis ground. If resistance is less than one ohm, go to next step. If resistance is not less than one ohm, repair open in Black wire between fuel pump and ground.
- With relay connected, ensure battery voltage is present at relay terminal White/Red wire. For locations of fuel pump relay, see FUEL PUMP RELAY LOCATIONS table.
- If voltages are okay, remove relay from vehicle. Using a 12-volt battery source, connect 12 volts to relay terminals "A" and ground terminal "B". Ensure continuity is present across terminals "C" and "E". See Fig 1 . If continuity is not as specified, replace fuel pump relay.
FUEL PUMP RELAY LOCATIONS
| Application | Location |
|---|---|
| Miata | Under Dash, Left Of Steering Column |
FUEL PUMP CONNECTOR WIRE IDENTIFICATION
| Application | Battery Positive | Ground |
|---|---|---|
| Miata | Blue/Red | Black |