Fuel Pump: Testing and Inspection

Fig. 24 Fuel Pump Bypass Terminal I.D.:

1. Ensure that battery is fully charged and that fuse is not defective.
2. Remove electrical connector from control pressure regulator and auxiliary air regulator.
3. Remove rear cover in left side dashboard compartment.
4. Ensure that 16 amp fuse on top of fuse box is OK.
5. Ensure that in-line fuse is not defective, if used.
6. Remove fuel pump relay and connect jumper wire with an in-line switch (US4480/3 or equivalent) across sockets to energize the fuel pump circuit, Fig. 24.
Do not open fuel tank cap until after fuel delivery rate has been checked.
7. Ensure that fuel filter is clean and properly installed.

Fig. 64 Hardware Needed To Check Fuel Pump output:

NOTE: For the next steps you will need, Fig. 64;
1 - hollow 12 X 1.5 banjo bolt
2 - copper washers
1 - M 8 X 1.25 (20mm long) conventional bolt
1 - M 8 X 1.25 acorn nut
2 - copper washers

8. Disconnect flexible fuel return line (between the air flow sensor and the fender) where it connects to the metal fuel tank return line.
9. Disconnect the flexible return line at the frequency valve.
10. Disconnect the metal fuel line from the frequency valve.
11. Use the M 8 bolt, acorn nut and copper washers to seal the banjo fitting on the frequency valve.
12. Use the 12 X 1.5 banjo bolt, and copper washers to attach the flexible line to the banjo fitting on the solid line (the line previously connected to the frequency valve), to direct the fuel flow into a graduated container.
13. Turn the fuel pump relay jumper wire switch ON for 30 seconds.
14. Fuel delivery rate should be:
1000 ml @ 12 volts
850 ml @ 11 volts
700 ml @ 10 volts
550 ml @ 9 volts
15. If fuel pump output is not within specification, check:
Fuel filter for clogging,
Fuel lines for kinks or blockages.
Fuel pickup in the fuel tank for clogged pickup screen
16. If the fuel flow path is OK, check the voltage supply and current draw of the fuel pump.
17. Disconnect electrical connectors at fuel pump under the car, connect voltmeter across leads and turn fuel pump relay jumper wire switch ON. Battery voltage must be available. Do not let positive connection contact ground.
18. Turn fuel pump relay jumper wire switch OFF, then connect ground lead to fuel pump.
19. Connect ammeter between positive lead and fuel pump terminal. Turn fuel pump relay jumper wire switch ON and check amperage. Amperage draw should not be more than 8.5 amps. Do not let positive connection contact ground.
20. If amperage exceeds 8.5 amps, replace fuel pump.
21. Turn jumper wire switch OFF, remove ammeter and attach wires to fuel pump.