How to Remove Water From a Car's Fuel System

by Jack Hathcoat
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Occasionally, filling a fuel tank results in water being introduced into the fuel system. This happens when a service station storage tank develops a leak and ground water seeps in. Water is heavier than gasoline and sinks to the bottom of the car's gas tank. When this happens, the fuel pump distributes the water throughout the fuel lines and to the fuel injectors. This quickly locks the engine and causes it to stop running. Completely removing all of the water is the only option.

Step 1

Raise the hood of the car, and use a wrench to disconnect the car's negative battery cable. Jack up the rear of the car, and install jack stands under the frame.

Step 2

Drain the fuel tank. If the fuel tank has a drain plug, remove it with a wrench and drain the fuel and water mixture into suitable containers. If not, remove the fuel tank straps with a socket wrench and use a jack lower the fuel tank. Remove the fuel line hoses with a screwdriver, disconnect the electrical connector that powers the fuel pump, and pull the tank from under the car.

Step 3

Remove the fuel pump from the tank by removing the retaining ring or retaining screws that hold the pump in place. Empty the tank into containers that will hold the contaminated fuel. Replace the fuel pump when the tank is empty and reinstall it in the car. Add several gallons of fresh gasoline to the tank.

Step 4

Remove the ignition fuse or disconnect the ignition coil. Disconnect the fuel rail from the engine, and remove the fuel injectors. Remove the spark plugs. Flush the fuel rail with cleaning solvent, such as mineral spirits or toluene. Reconnect the battery, and have an assistant turn the key on. Catch the fluid that is discharged from the fuel line running from the fuel tank to the engine. Allow the car to set overnight to evaporate any water inside the engine cylinders.

Step 5

Replace the fuel rail and injectors, and install new spark plugs. Reconnect the fuel lines and ignition coil. Replace the ignition fuse if it was removed. Start the car and allow it to run until it reaches operating temperature. The exhaust might steam as the water and fuel mixture inside the exhaust system is burned off.

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