GM 6471172 Fuel Pump Assembly

For every carbureted engine, there's a single-action mechanical fuel pump built with a small spring to hold the rocker arm against an always-moving camshaft eccentric. When the rocker arm goes up, fuel links pull down the diaphragm. This action widens the fuel chamber and sucks fuel from the tank. Fuel moves to the carburetor when line pressure drops below what the spring holds inside the diaphragm. The fuel pumps on Regal models come sealed and must get replaced when they stop working correctly. To take out the mechanical fuel pump, find it, detach the fuel hoses, remove the holding bolts, and throw away the seal. Before placing the new pump and gasket on the engine, remove all gasket material from its contacts, and once the engine starts, double-check for fuel leaks as the fuel lines are connected again. Before checking the pump, test between the fuel tank and the pump on one side and from the pump to the carburetor on the other side. Pressure leak shows at fuel spilling, but suction leak only becomes obvious when the engine stops. Check and tighten any weak parts in the fuel system, while making sure your tubes are smooth and straight. After unplugging the fuel pump from the carburetor, turn the engine by hand. If no or little fuel comes through, you may need to clear debris from the fuel pipe or replace the pump. Run the engine between 450 and 1,000 rpm. When the fuel flows properly, check the fuel pressure with a gauge. If the gauge shows fuel pressure that meets spec limits, leave the pump; but swap it if not.

The 1986-87 port injected turbocharged V6 engines incorporate an electric fuel pump mounted internally within the fuel tank, requiring tank removal to get at the pump. Before removal of fuel lines it is necessary to release pressure in fuel system to avoid such a dangerous phenomenon as high-pressure fuel spray; and all sources of fire, spark or naked flame must be omitted from work area. First remove the power supply to fuel pump and crank the engine until the engine dies and turn on the starter to release the pressure from fuel pump. Remove the negative battery terminal and then to proceed to empty the fuel tank if possible, using either a pump or a siphon prominently. Lift up the vehicle high enough as recommended for tank removal and then stabilize the tank and the supporting strapping bolts and spacers. Slowly pull the tank down in order to remove the terminal of the fuel gauge sending unit then set the tank aside. Leverage and pull the cam locking ring and then remove the fuel gauge sending unit/pump assembly then remove the pump assembly attached to the sending unit check for damages at the attaching hose and the rubber sound insulator. Replace the new pump assembly with the new O-ring and put back the tank in reverse as mentioned above. For fuel system pressure testing, connect the harness and bring the ignition ON;To check the pump, ensure it runs and confirming fuel pressure values. If pressure is out of that range, electric FOR, look for leakage, ensure pressure control regulator and fuel filter from contaminants. Should further tests be required, one needs to pinch the fuel return line and check the pressure in order to diagnose fuelling related problems with the fuelling system's components. Before doing any work on all of the fuel system elements, there must be a discharge of the fuel system pressure.

Install the pump with a new gasket, ensuring that on the 231 V6 engine, the fuel pump is positioned correctly and that its rocker arm makes contact with the camshaft, applying gasket sealant to the screw threads.

Finally, operate the starter motor and observe for well-defined spurts of fuel ejected from the open end of the line.

The fuel pump is a sealed type.

A test can be performed by following these steps: 1. Ensure there is gas in the fuel tank. 2. For 1974 models, disconnect the primary wire running between the coil and the distributor to prevent engine firing when the starter motor is engaged. For 1975 to 1980 models, disconnect the distributor wiring marked 'BAT.' 3. Disconnect the fuel inlet pipe from the carburetor and place its open end in a container. 4. Operate the starter motor and observe for well-defined spurts of fuel ejected from the open end of the pipe.

The final step is to reconnect the fuel pipes, start the engine, and check for any leaks.