Question 1

The amperage draw of an electric fuel pump is higher that specified. What could be the cause?

Accepted Answer

A higher than specified amperage draw by an electric fuel pump can be caused by a clogged fuel filter, a defective fuel pump, or a restriction in the fuel line. Each of these conditions can make the pump work harder, increasing its electrical demand.

Question 2

The amperage draw of an electric fuel pump is lower than specified. What is the most likely cause?

Accepted Answer

A

Question 3

Technician A says that a fuel tank is either constructed of steel with brass plating for corrosion resistance or of polyethylene plastic. Technician B says that some fuel tank filler tubes contain an anti-siphoning device. Which technician is correct?

Accepted Answer

Fuel tanks are typically made of steel or polyethylene plastic, but not steel with brass plating. Technician B is correct that some fuel tank filler tubes have anti-siphoning devices to prevent fuel theft.

Question 4

Technician A says that fuel tank accident and rollover protection devices include check valves and inertia switches. Technician B says that most fuel lines are made of ABS plastic. Which technician is correct?

Accepted Answer

Technician A is correct because fuel tank accident and rollover protection devices indeed include check valves and inertia switches to prevent fuel leakage and fire. Technician B is incorrect because most fuel lines are made of materials like steel or nylon, not ABS plastic.

Question 5

Technician A says that electric fuel pump types include roller cell, gerotor, and turbine. Technician B says that fuel filters remove particles that are 10 to 20 microns or larger in size. Which technician is correct?

Accepted Answer

Technician A is correct as electric fuel pump types include roller cell, gerotor, and turbine. Technician B is also correct as fuel filters typically remove particles that are 10 to 20 microns or larger in size. Therefore, both technician A and B are correct.

Question 6

How long does the electric fuel pump run if the ignition is turned on but the engine is not started?

Accepted Answer

The electric fuel pump typically runs for just a few seconds when the ignition is turned on but the engine is not started, as it needs to prime the fuel system before the engine can start.

Question 7

The electric fuel pump is usually mounted in which of these locations?

Accepted Answer

The electric fuel pump is typically located inside the fuel tank. This allows it to draw fuel from the tank and pump it to the engine with greater efficiency. Some older vehicles may have an external fuel pump mounted near the engine, but this is less common in modern cars. Internal fuel pumps also have the benefit of being more protected from damage and wear, as they are not exposed to as much dirt, debris, or heat as external pumps.

Question 8

Some General Motors electric fuel pump circuits incorporate a(n) ________ that functions as a back-up circuit to energize the fuel pump relay.

Accepted Answer

Some General Motors vehicles have an oil pressure switch that is wired to a fuel pump relay as a back-up circuit. If the fuel pump relay fails to energize, the oil pressure switch will provide power to the fuel pump. This is a safety feature that ensures the fuel pump continues to operate even if the fuel pump relay fails.

Question 9

Fuel pump pressure is too low after engine start-up. Which of these could be the cause?

Accepted Answer

A plugged fuel filter can restrict the flow of fuel to the engine, resulting in low fuel pressure after start-up. The other choices (A, B, and C) are less likely to cause this issue.

Question 10

Which of these is the fuel pump?

Accepted Answer

The answer of Which of these is the fuel pump?...

Question 11

Technician A says that fuel filters are located in the fuel supply line. Technician B says that fuel filters are located in the fuel return line. Which technician is correct?

Accepted Answer

Fuel filters are generally located in the fuel supply line and not in the fuel return line. As fuel flows from the fuel tank to the engine, it passes through the fuel filter which removes impurities and contaminants that may clog fuel injectors or damage other engine components. The fuel then reaches the engine where combustion takes place, and the unused fuel is returned back to the fuel tank through the fuel return line. Therefore, technician A is correct in this case.

Question 12

Technician A says that a pressure check valve should hold system pressure for at least five minutes after the pump is shut off. Technician B says that a defective check valve could cause long cranking time. Which technician is correct?

Accepted Answer

Technician A is correct, as a pressure check valve is designed to hold system pressure for a certain amount of time after the pump is shut off. 
Technician B is also correct, as a defective check valve can cause long cranking time because it can lead to fuel system pressure loss. Hence, both technicians A and B are correct.

Quiz 21: Fuel Pumps, Lines, and Filters