Fuel Pump: Description and Operation

FUEL PUMP

DESCRIPTION

V8
The fuel pump fitted on V8 vehicles is mounted in the plastic fuel tank, and supplies fuel at a constant 3.5 bar pressure to the fuel rail. The fuel rail distributes fuel evenly to each of the eight injectors.

OPERATION

V8
Power Distribution
Feed from the positive battery terminal (C0192) is supplied to fusible link 2 and fusible link 5 of the passenger compartment fuse box (C0632) on an R wire. Fusible link 2 (C0591) provides a constant battery feed to the Engine Control Module (ECM) relay (C1895) on an R wire.

Fusible link 5 of the passenger compartment fuse box (C0588) is connected to fuse 15 of the rear passenger compartment fuse box (C2024) by an R wire. Fuse 15 provides a constant battery feed to the fuel pump relay, which is also located in the rear fuse box.

ECM Relay
Fusible link 2 of the passenger compartment fuse box (C0591) provides a constant battery feed to the ECM relay coil (C1895) on an R wire. The earth path for the relay coil (C1895) is controlled by the ECM (C0604) on an N wire. The energised ECM relay (C1895) provides a feed to fuse 51 of the passenger compartment fuse box (C0584) on an RW wire. Fuse 51 (C0585) supplies a feed to the fuel pump relay coil (C2022) on an RW wire.

Fuel Pump Relay
The fuel pump relay coil (C2022) receives a feed from fuse 51 of the passenger compartment fuse box (C0585) on an RW wire. The earth path for the relay coil (C2022) is controlled by the ECM (C0331) on a BP wire. The energised fuel pump relay provides a battery feed from fuse 15 of the rear fuse box to the fuel pump (C0114) on a WU wire. The fuel pump is earthed on an N wire.