The following checks assume the fuel filter is in good condition; if there are doubts about its condition, a new one should be installed. First, ensure there is adequate fuel in the tank; if the gauge reading is questionable, use a long wooden dowel as a dipstick. For carbureted vehicles, raise the vehicle securely and, with the engine running, inspect all fuel lines for leaks, loose connections, kinks, or flattening in the rubber hoses, doing this quickly before the engine heats up. After shutting off the engine, check the pump body for leaks, relieve fuel tank pressure by removing the filler cap, and disconnect the fuel line at the carburetor. Disconnect the ignition coil's primary wiring connector to crank the engine without firing, placing an approved gasoline container at the end of the detached fuel line; a strong spurt of gasoline should emerge on every second revolution. If little or no gasoline is present, the fuel line may be clogged or the pump may not be functioning properly. For electric pumps in fuel-injected vehicles, while the best method to check operation is with a fuel pressure gauge, it is possible to check if the pump is receiving power by turning the ignition key to the ON position and listening for a whirring sound. If the pump is not working, check the fuse and then the fuel pump relay, testing it according to the model year specifications. If the pump still does not work, check the relay circuit. To check fuel pressure, relieve it first, then install a fuel pressure gauge and turn the ignition switch to ON, allowing the pump to run for about two seconds. After cycling the key several times, the pressure reading should stabilize within the specified range. If the pressure is too high or low, inspect the fuel filter, hoses, and connections for clogs or leaks, and check the fuel pump's voltage and connections. After testing, relieve the fuel pressure and remove the gauge.
Posted by GMPartsGiant Specialist 
