Chevrolet 6471929 Fuel Pump Assembly

For carbureted engines, ensure sufficient fuel, inspect fuel lines for leaks or damage, and test for a strong gasoline spurt when cranking the engine. If weak, assess the fuel pump and its flow capacity; it should pump a pint in 30 seconds. For fuel-injected engines, listen for the pump's whirring noise on ignition. If silent, inspect the fuse, relay, and circuit. To test the pump, apply battery voltage to its gray wire terminal. To verify the relay, use a test light and jumper wire. If there's an issue with fuel pressure, connect a gauge and check when the ignition is on. Low pressure might indicate a defective regulator, and high pressure could signify a blockage or faulty regulator. On MPFI models, check the regulator's function by observing pressure changes when detaching its vacuum hose.

After cleaning the block mounting surface and applying grease to the pushrod, the new gasket and pump should be installed and the hoses and lines should be reattached.

If needed, the fuel pump can be separated from the sending unit.

The initial steps involve checking the fuel tank to ensure it has enough fuel. While the engine is running, inspect all fuel lines for leaks, loose connections, or any damage. Additionally, check for air leaks before the fuel pump, as this can affect its performance.

The next steps involve detaching the fuel inlet hose, outlet line, and vapor return hose, removing the mounting bolts, and retrieving the pushrod.

For fuel-injected models, start by verifying that the fuel pump is running by listening for a whirring noise when the ignition switch is turned on. If the pump does not come on, check the fuel pump fuse and relay. If they are both functioning properly, check for an open circuit between the relay and the fuel pump. If the circuit is fine, disconnect the electrical connector at the fuel pump and connect battery voltage to the gray wire terminal of the pump to see if the pump runs.