Section 3

FUEL PUMP - OUTLINE OF DIAGNOSTICS, PARTS ORDERING AND WARRANTY APPLICATION

Section 3 - FUEL PUMP DIAGNOSTIC PROCEDURES

1. Disconnect negative terminal and check battery voltage. Voltage should be 12.4V or more. Reconnect terminal.

2. Start engine and run at idle.

3. Disconnect circuit opening relay. Engine will continue to run until all fuel in the supply line is used.

WARNING:
Step 3 is designed to eliminate fuel in the supply line and enable safe installation of the fuel pressure gauge. Refer to the workshop manual for further instructions.

4. Disconnect the negative battery terminal.





5. Install the fuel pressure gauge on the outlet side of the fuel filter.





6. Short circuit the fuel pump test terminals (yellow 2 pin connector with a jumper wire on the following vehicles.

1988 - 89 323 1993 - 626/MX-6

1990 - 91 929 1989 - 92 MPV

1989 - 91 RX-7

7. Short circuit the fuel pump check terminal and the ground terminal of the diagnostic connector with a jumper wire on the following vehicles.

1990 - 93 323/Protege 1993 - 626/MX-6

1992-93 929 1992 - 93 MX-3

1990 - 93 MX-5 1993 RX-7





8. Turn the ignition switch on and measure the maximum fuel pressure. Turn the ignition switch off and remove the jumper wires.





9. If the value of fuel pressure (Max.) is below standard, measure the voltage at the fuel pump connector (vehicle side) using the procedures below.

a) Reinstall the jumper wire and turn the Ignition on. Refer to steps 6 and 7.

b) Connect test leads to the fuel pump positive and negative terminals and measure the voltage at the fuel pump connector (vehicle side).

NOTE:
Do not disconnect the fuel pump connector.

If the voltage is above the standard value, replace the fuel pump.

If the voltage is below standard, check for a damaged harness, relay or a poor ground at the pump.

Standard Value: 8.5V and over (93 RX-7)
9.5V and over (Other Models)

10. After restoring the standard voltage value, measure the fuel pump pressure (Max.). If pressure is not to specification, replace the fuel pump.

11. If no trouble is found with the fuel pump and the problem still exists, contact the Technical Hotline for assistance.





FUEL PUMP CHECK SHEET

NOTE:
Attach the check sheet to the repair order. If requested to return the failed fuel pump to Mazda, attach a copy of the check sheet and repair order.