Main Fuel Pump Testing

Fig. 53 Fuse/Relay Panel, Jetta:

Avoid sparks or open flame when checking fuel pump delivery rate.
1. Connect jumper wire, in place of fuel pump relay, Fig. 1.
2. Disconnect oxygen sensor heating element.
3. Disconnect electrical connectors at fuel pump, connect voltmeter across leads and turn jumper wire switch on. Minimum voltage must be 11.5 volts. Do not let positive connection contact ground.
4. Turn jumper wire switch off, then connect ground lead to fuel pump.
5. Connect ammeter between positive lead and fuel pump, then turn jumper wire switch on and check amperage. Amperage draw should not be more than 8.5 amps. Do not let positive connection contact ground.
6. If amperage exceeds 8.5 amps, replace fuel pump.
7. Turn off jumper wire switch, remove ammeter and attach connector to fuel pump. Do not open fuel tank cap until after fuel delivery rate has been checked.
8. Disconnect line from fuel pump at input to fuel filter and collect fuel in suitable calibrated container.
9. Run fuel pump for 30 seconds.
10. Fuel delivery rate should be:
675 ml @ 12 volts
510 ml @ 11 volts
400 ml @ 10 volts
225 ml @ 9 volts
11. If delivery rate is not within specification, replace fuel pump.