Fuel Pump Circuit Wiring Diagram (1994-1995 3.1L V6 Buick Century)

APPLIES TO: This fuel pump circuit wiring diagram applies to the following vehicles:

• 3.1L V6 Buick Century: 1994, 1995.

Basic Operating Theory Of The Fuel Pump Relay

The fuel pump relay's job is to supply battery power to the in-tank fuel pump whenever the engine needs fuel pressure.

When you first turn the ignition key to the ON position (without cranking the engine), the PCM energizes the fuel pump relay for about 2 seconds. This briefly runs the fuel pump to build fuel pressure before the engine starts.

If the engine isn't cranked within those 2 seconds, the PCM turns the relay back OFF. Once the engine begins cranking and the PCM receives ignition reference signals, it energizes the relay again, allowing the fuel pump to run continuously.

As a backup system, the fuel pump can also receive power through the engine oil pressure switch. This switch is normally open and closes when engine oil pressure reaches about 4 PSI (28 kPa). If the fuel pump relay fails, the closed oil pressure switch can still power the fuel pump once the engine develops enough oil pressure.

A failed fuel pump relay can cause extended cranking or a no-start condition. Since the oil pressure switch doesn't close until oil pressure builds, the engine may have to crank longer than normal before it starts.

FUEL PUMP TESTS: How To Test The Fuel Pump (1994-2005 3.1L V6 Buick Century).

Other Fuel Pump Wiring Diagrams

• Fuel Pump Circuit Wiring Diagram (1996 3.1L V6 Buick Century).
• Fuel Pump Circuit Wiring Diagram (1997 3.1L V6 Buick Century).
• Fuel Pump Circuit Wiring Diagram (1998-1999 3.1L V6 Buick Century).
• Fuel Pump Circuit Wiring Diagram (2000-2001 3.1L V6 Buick Century).
• Fuel Pump Circuit Wiring Diagram (2002-2005 3.1L V6 Buick Century).

More 3.1L V6 Buick Century Tutorials

You can find a complete list of 3.1L V6 Buick Century tutorials and wiring diagrams in this index:

• 3.1L V6 Buick Century Index of Articles.

Here's a sample of the tutorials you'll find in the index:

• How To Test The TPS With A Multimeter (1997-2005 3.1L V6 Buick Century).
• Common Causes Of Spark Plug Failure (1994-2005 3.1L V6 Buick Century).
• How To Test For A Blown Head Gasket (1994-2005 3.1L V6 Buick Century).
• How To Test Engine Compression (1994-2005 3.1L V6 Buick Century).