Working Safely on Your Fuel System

Working on any part of the fuel delivery system exposes you to risks. Whether swapping out the pump on a ‘97 Taurus or replacing fuel injectors on an ‘05 Camry you’re likely to come into contact with gasoline. This note provides some education on the hazards involved in working on the fuel systems and some guidance for how to stay safe.

Fire hazard

Gasoline burns readily so it’s very important to eliminate all potential sources of ignition. Disconnect the battery at the negative terminal to prevent electrical sparks and never smoke or allow an exposed flame near where you’re working.

Keep a Class B fire extinguisher close by: this type uses inert gas or powder to suffocate a fire. Never use a Class A water fire extinguisher on gasoline!

If rags or shop towel become soaked in gasoline, be sure to dispose of them carefully.

Health hazard

According to the CDC, gasoline vapors will irritate the lungs when inhaled. They can cause dizziness and headaches and in extreme cases hallucinations and even suffocation. For these reasons always try to do fuel system work in a well-ventilated garage or the open air. The CDC does however say, “there is no evidence that exposure to gasoline causes cancer in humans.”

Gasoline can irritate the eyes and skin, and if swallowed, the stomach lining. It can even lead to liver and kidney damage in extreme cases.

The fuel system

The most hazardous part of the fuel system is the fuel rail and supply line from the pump. This is where gasoline is held under pressure, and in modern, direct injection engines those pressures are getting ever higher. Never attempt to work on any part of the system from pump to fuel pressure regulator without first relieving the pressure.

Pressure is best relieved in one of two ways:

Remove the fuel pump fuse or relay and run the engine until it stalls.

Many vehicles have a schrader-type fitting, (like the valve on a tire,) somewhere on the high-pressure fuel line. This is so a pressure gauge can be connected. Just as with a tire, it is possible to relieve the fuel pressure with this valve: use a shop towel or rag to prevent gas from spraying.

Personal protective equipment

It’s always advisable to wear safety glasses when doing any car repair work: you never know when a hose will burst or something fly up. Modern glasses are inexpensive and lightweight.

Latex gloves are also very useful. As they are tight and thin they do little to reduce ‘feel’ but keep gas, grease and oil off your skin. They also cut down on the amount of clean up time needed!

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