1993 Fuel Pump Circuit Tests (GM 4.3L, 5.0L, 5.7L)

Fuel Pump Relay Wiring Diagram (Automatic Transmission Only)

NOTE: The wiring diagram illustrations in this article cover only: 1993 4.3L, 5.0L, and 5.7L GMC/Chevrolet pickups with the 4L60-E automatic transmission. For the 1994 fuel pump wiring diagram, check out the following article:

• 1994 Fuel Pump Circuit Tests (GM 4.3L, 5.0L, 5.7L).

Fuel Pump Relay Diagnostic/Troubleshooting Notes:

• FP relay terminal A (ORG wire):
  • Should have 10 to 12 Volts DC with Key On Engine Cranking or Key On Engine Running (KOER).
  • This voltage comes from the GRY inline fusible link located in the engine compartment junction block.
• FP relay terminal E (GRY wire):
  • Should have 10 to 12 Volts DC when the engine is being cranked and relay has activated.
• FP relay terminal D (BLK/WHT wire):
  • Should have Ground all of the time.
• FP relay terminal F (DK GRN/WHT wire):
  • Power supplied by the PCM to the FP relay coil to activate the relay.

Fuel Pump Relay Wiring Diagram (Manual Transmission Only)

NOTE: The wiring diagram illustrations in this article cover only: 1993 4.3L, 5.0L, and 5.7L GMC/Chevrolet pickups with the 4L60-E automatic transmission.

Fuel Pump Relay Diagnostic/Troubleshooting Notes:

• FP relay terminal A (ORG wire):
  • Should have 10 to 12 Volts DC with Key On Engine Cranking or Key On Engine Running (KOER).
  • This voltage comes from the GRY inline fusible link located in the engine compartment junction block.
• FP relay terminal E (GRY wire):
  • Should have 10 to 12 Volts DC when the engine is being cranked and relay has activated.
• FP relay terminal D (BLK/WHT wire):
  • Should have Ground all of the time.
• FP relay terminal F (DK GRN/WHT wire):
  • Power supplied by the PCM to the FP relay coil to activate the relay.

Fuel Pump Wiring Diagram

Fuel Pump Troubleshooting Notes:

• Oil pressure switch:
  • If the fuel pump relay fails, what usually happens is that the oil pressure switch feeds power to the fuel pump and gets the engine started and keeps it running.
  • When this happens, the engine will crank till the oil pressure gets up and the oil pressure switch closes.

Location Of The Fuel Pump Relay Components

	Fuel pump in-line fuse -20 Amp.
	Junction block.
	Fuel pump relay.

Where To Buy The Fuel Pump And Save

You can find the fuel pump and fuel pump strainer filter in any auto parts store. If you're wanting the buy the original AC Delco (Delphi) fuel pump and fuel pump strainer filter, you can buy it online for a whole lot cheaper than somewhere local.

The following links will help you comparison shop for the AC Delco (Delphi) and after market fuel pump and fuel pump strainer filters:

Will the above fuel pump and fuel pump strainer filter fit your particular GM pickup? Don't worry, once you get to the site they'll make sure it fits (by asking you the specifics of your particular vehicle). If it doesn't fit, they'll find you the right one.

More GM 4.3L, 5.0L, 5.7L Tutorials

You can find a complete list of tutorial in this index: GM 4.3L, 5.0L, 5.7L Index Of Articles.

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

• How To Test The Blower Resistor (1988-1993 Pickups).
• How To Test The Blower Motor (GM 4.3L, 5.0L, 5.7L).
• How Can I Tell If My 4L60-E Transmission Is Bad?
• Shift Solenoid A And B Tests (GM 4.3L, 5.0L, 5.7L).
• How To Test The Engine Compression (GM 4.3L, 5.0L, 5.7L).
• How To Test The GM Distributor Mounted Ignition Module (at: easyautodiagnostics.com).