Question

pressure builds - up quickly on engine restarts.
due to the high pressure and flammability of fuel, loosening a fuel line when the engine is running is very dangerous! fuel will rush out and may come in contact with a hot exhaust pipe, potentially starting a fire! same thing can happen if you loosen a line when the engine is off, due to the residual pressure, if you dont first depressurize the system. therefore always consult manufacturer service information to determine the correct procedure for relieving residual fuel pressure before you loosen any fuel line connection.
another potential hazard of the injection system is the high voltage used in piezo injectors on some diesel engines. the voltage can be as high as 400 volts; so pay close attention when working on them and always follow manufacturer service precautions and service procedures.
safety recommendations:

• always wear safety glasses.
• wear disposable gloves that are resistant to fuel.
• always use line wrenches to loosen fuel line fittings, never use an open - end wrench that can slip.
• never smoke or have an open flame or torch around the fuel tank lines and hoses.
• know where the shop fire extinguishers are located. aim extinguisher at the base of the fire.

1
evaluate the following statements regarding fuel injection system safety.
fuel injection systems must be depressurized before you can safely loosen a line.
taking off any fuel system part while the engine is running is highly dangerous, fuel will rush out!
the two main hazards related to fuel injection system are: fuel spills and electrical shock by the driving voltage of some type of fuel injectors.
you can test the driving voltage of a piezo injector with a test light designed for normal port - injection petrol injectors.

Explanation:

1. The text states that due to residual pressure, fuel injection systems must be depressurized before loosening a line to avoid fuel - related hazards.
2. It clearly mentions that loosening a fuel line when the engine is running is very dangerous as fuel will rush out.
3. The text highlights high - pressure fuel spills and high voltage (up to 400 volts in Piezo injectors) as the two main hazards.
4. There is no mention in the text about testing the driving voltage of a Piezo injector with a test light for normal port - injection petrol injectors, so this statement is not supported.

Answer:

Fuel injection systems must be depressurized before you can safely loosen a line. - True
Taking off any fuel system part while the engine is running is highly dangerous, fuel will rush out! - True
The two main hazards related to fuel injection system are: fuel spills and electrical shock by the driving voltage of some type of fuel injectors. - True
You can test the driving voltage of a Piezo injector with a test light designed for normal port - injection petrol injectors. - False