Possible Reasons:
* Mechanical Failure:
* Worn out diaphragm: The diaphragm is the heart of the pump, and over time it can wear out, tear, or become brittle, preventing it from creating suction and pushing fuel.
* Seized or worn out pump arm: The pump arm connects to the engine camshaft and can become stuck or worn, preventing the pump from cycling.
* Clogged fuel lines: Debris or rust can clog the fuel lines, restricting fuel flow and preventing the pump from working properly.
* Broken pump rod: The rod connecting the pump arm to the diaphragm can break, rendering the pump useless.
* Electrical Problems (for electric fuel pumps):
* Blown fuse: Check the fuse related to the fuel pump (if it's electric).
* Faulty relay: The fuel pump relay controls the flow of electricity to the pump.
* Wiring issues: A broken or corroded wire to the fuel pump can disrupt the electrical connection.
Diagnosis and Troubleshooting:
1. Listen for the pump: With the engine off, have someone crank the engine while you listen near the fuel pump. You should hear a whirring noise if the pump is working.
2. Check for fuel pressure: A fuel pressure gauge connected to the fuel line will show you if the pump is generating pressure.
3. Inspect the fuel lines: Look for any kinks, leaks, or blockages.
4. Check the fuel pump arm: Make sure it's moving freely and connected to the camshaft.
5. Visual Inspection: If you can access the pump, check for signs of damage, leaks, or wear.
Important Notes:
* 1991 Mazda B2200 Fuel Pump: The 1991 Mazda B2200 likely has a mechanical fuel pump, which is driven directly by the engine camshaft. It doesn't use an electric pump.
* Safety First: Always disconnect the battery before working on the fuel system. Fuel is highly flammable!
* Professional Help: If you are uncomfortable troubleshooting the fuel system, it is best to take your vehicle to a qualified mechanic.
Let me know if you can provide more details about the specific symptoms you are experiencing, and I can offer more specific troubleshooting advice!
