* Fuel Pump: The fuel pump is a mechanical device that sits inside your fuel tank and is responsible for moving fuel from the tank to the engine. It's a vital part of the fuel system.
* Fuel Pump Relay: The relay is an electrical switch that controls the flow of electricity to the fuel pump. It acts as a middleman, receiving a signal from the engine control module (ECM) to turn the pump on and off.
Think of it this way:
* Fuel pump: The engine that powers the car.
* Relay: The switch that turns the engine on and off.
Here's how they work together:
1. When you turn the key to the "on" position, the ECM sends a signal to the fuel pump relay.
2. The relay then closes, allowing electricity to flow to the fuel pump.
3. The fuel pump starts running and delivers fuel to the engine.
4. When the engine is off, the ECM stops sending the signal, the relay opens, and the fuel pump stops.
Important: A faulty relay can prevent the fuel pump from working, even if the pump itself is in good condition.
If you're experiencing fuel problems with your 1990 Mustang, it's a good idea to check both the fuel pump and the relay.
