Fuel Relay Diagnosis in a 1994 Chevrolet 1500by Giovanni Badalamenti
Occasionally, the 1994 Chevrolet 1500 might develop problems with its fuel relay system. Some simple diagnosis techniques can often resolve the problem. While troubleshooting, wear protective gear and keep a class B fire extinguisher nearby.
The fuel relay is located on the passenger side fire wall, "near the top of the compartment under the relay cover," according Haynes manuals. Mounted about 6 inches to the right of the fuel pump fuse, it's black with five wires coming out of the bottom.
Examine fuel lines for a leak or crimped hose (or fuel line) impeding the flow of fuel to the carburetor. Have someone turn the ignition on while you listen for the fuel pump (located in the fuel tank) to activate. A whirring sound can be heard for approximately two seconds when the fuel pump is working properly. If there is no sound, turn the ignition off and remove the cover from the underhood fuse/relay center. Using the guide printed under the cover, locate the fuel pump relay fuse. Examine it for usability. Replace if the element is broken.
Next, test for electrical current by performing a voltage check. If the fuses and relay are good, check the fuel pump relay control circuit from the relay to the engine control module/powertrain control module (ECM/PCM). If the circuit is good, have the ECM/PCM diagnosed and serviced by an authorized repair shop or dealership.
- Haynes Repair Manual: "Chevrolet & GMC Pickups. 1988 thru 1998", 2001
- Jose Nieto, ASE Certified Mechanic, Manager,Tuffy Auto Repair, Sanford, Florida
- Jason Smith/Getty Images Sport/Getty Images