Mercury 7L8Z-9H307-B Sender And Pump Assembly

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The fuel pump is located inside the fuel tank, which muffles its sound when the engine is running. However, you can hear the fuel pump if you sit inside the vehicle with the windows closed, turn the ignition key to ON and listen carefully for the whirring sound made by the fuel pump as it's briefly turned on to pressurize the fuel system prior to starting the engine. If you can't hear the pump, remove the fuel filler cap, depress the spring-loaded door inside the fuel filler neck, then have an assistant turn the ignition switch to ON while you listen for the sound of the pump being primed.If the pump does not come on when the ignition key is turned to ON, check the fuel pump fuse and relay located in the engine compartment fuse and relay box. If these are okay, check the wiring back to the fuel pump. If the fuse, relay and wiring are okay, the fuel pump is probably defective. If the pump runs continuously with the ignition key in its ON position, the Powertrain Control Module (PCM) is probably defective and should be checked by a dealer service department or other qualified repair shop.To check the fuel pressure on a V6 engine, you'll need a fuel pressure gauge with an adapter that fits the Schrader valve on the left end of the fuel rail. Four cylinder engines do not have a Schrader valve, so you will need to obtain a fuel pressure gauge with which you can tee into the fuel system at a suitable fuel line fitting. To connect a fuel pressure gauge to the Schrader valve test port, first screw on the adapter, then hook up the fuel pressure gauge. On four-cylinder models, you'll have to tee into the fuel system at the connection between the fuel supply line and the fuel rail.Start the engine and allow it to idle. Note the gauge reading as soon as the pressure stabilizes, and compare it with the pressure listed in the specifications. If the pressure is lower than specified, check the fuel lines and hoses for kinks, blockages and leaks. Check the fuel strainer for restrictions. If all these components are okay, the fuel filter could be clogged or the fuel pump module could be defective. If the fuel pressure is higher than specified, replace the fuel pump module.Turn off the engine and verify that the fuel pressure stays at the specified level for five minutes after the engine is turned off. Then disconnect the fuel pressure gauge, making sure to cover the fitting with a rag before loosening it. Mop up any spilled gasoline. Start the engine and verify that there are no fuel leaks.

The Multiport Fuel Injection (MFI) system includes the fuel tank, electric fuel pump/fuel level sending unit module, fuel rail, pulsation damper, fuel injectors, and fuel lines.

After folding the rear seat cushion, the carpeting covering the fuel pump/fuel level sending unit module access cover should be removed.

The first step is to relieve the residual pressure in the fuel system and equalize tank pressure by removing the fuel filler cap.