Fuel pump relay (102): Connection
PIN DESCRIPTION
| Pin No. | Signal type | Description |
|---|---|---|
| 1 (86) | Control | Relay coil control lead. Supplied B+ from ECM pin 51(A). |
| 2 (85) | Ground | Relay coil's ground from ECM. |
| 3 (30) | +30 | Power supply to the relay contact from fuse 2 (729). |
| 5 (87) | Output, B+ | Relay switch's output. |
The fuel pump relay is controlled from pin 51(A), which is grounded so that the relay pulls. When the ignition is switched "ON", the fuel pump relay pulls for 1 second. This builds up pressure before preinjection, which occurs when the crankshaft begins to rotate.
When the crankshaft then rotates, relay 7 is pulled until the ignition leaves the ON position or the crankshaft stops rotating.