TEST YOUR AUTOMOTIVE TECHNICAL KNOWLEDGE
Copyright 2020 AA1Car.com & CarleySoftware.com
This self-test can help you determine how much you really know about this subject.
Questions are written in the ASE style format and are multiple choice.
The answer key is on the last page.
There are also links to related articles on the https://www.AA1Car.com website.
Good luck!
__________________________________________________________________
FUEL INJECTION SYSTEM SELF-TEST
1. A “MULTIPORT” (MPI) Fuel Injection system does what?
a. Sprays fuel directly into the cylinders
b. Sprays fuel into the throttle body
c. Sprays fuel into the intake manifold
d. Sprays fuel into the cylinder head ports
2. Technician A says Electronic Fuel Injection (EFI) can adjust the Air/Fuel mixture as
engine speed, temperature and load change.
Technician B says most EFI systems use a MASS AIRFLOW SENSOR (MAF) to monitor
the Air/Fuel mixture.
Who is right?
a. Technician A only
b. Technician B only
c. BOTH Technician A and B
d. Neither Technician A nor B
3. If the fuel pressure in an EFI system is LOW, how would it affect the Air/Fuel mixture?
a. It would make the A/F mixture RICH
b. It would make the A/F mixture LEAN
c. It would make the A/F mixture static
d. It would have NO effect on the A/F mixture
4. ANY of the following could cause LOW fuel pressure EXCEPT:
a. Clogged Fuel Injectors
b. Clogged fuel filter
c. Weak fuel pump
d. Leaky or defective fuel pressure regulator
5. In a RETURN style EFI system, the fuel pressure regulator is usually located where?
a. Inside the fuel tank
b. Between the fuel pump and fuel filter
c. On the fuel injector supply rail
d. Where the return line connects to the fuel tank
For the following questions, refer to the illustration above.
________________________________________________________________
6. What type of EFI system is shown in this illustration?
a. RETURN EFI system
b. RETURNLESS EFI system
c. THROTTLE BODY EFI system
d. DIRECT INJECTION EFI system
7. Which component is also part of the EVAP control system?
Fill in letter: ____
8. Which component generates pressure for the fuel injectors?
Fill in letter: ____
9. Which component is the FUEL PRESSURE REGULATOR?
Fill in letter: ____
10. Which component protects the fuel pump from rust or dirt inside the fuel tank?
Fill in letter: ____
11. Which component would be the FUEL PRESSURE SENSOR?
Fill in letter: ____
12. Which component vents excess fuel pressure back into the tank?
Fill in letter: ____
13. Which component would be used to test fuel pressure?
Fill in letter: ____
14. In this illustration of an EFI system, what does the OXYGEN SENSOR do?
a. Monitors exhaust pressure
b. Provides a feedback signal for the Air/Fuel mixture control system
c. Provides a feedback signal for adjusting fuel pressure
d. Monitors exhaust temperature
15. The Powertrain Control Module (PCM) changes what to adjust the Air/Fuel mixture?
a. Injector dwell (on time)
b. Injector pressure (up or down)
c. Injector voltage (up or down)
d. Injector timing (sooner or later)
16. In this illustration, what is flowing through the port ahead of the fuel injector?
a. Air
b. Air/Fuel mixture
c. Intake vacuum
d. Exhaust
17. Fuel spray from the Fuel Injector does what?
a. Atomizes the fuel
b. Cools the intake valve
c. Helps clean the intake valve
d. All of the above
18. If the above EFI system above is in OPEN LOOP mode of operation:
a. The Air/Fuel mixture is static (not changing)
b. The Air/Fuel mixture is changing
c. The PCM is using inputs from the Oxygen Sensor
d. The PCM is using inputs from the Downstream Oxygen Sensor
19. Following a COLD START, the Air/Fuel mixture is initially what?
a. Extra Lean
b. Extra Rich
c. Stoichiometric (neither RICH nor LEAN)
d. Varying
20. In the illustration above, which is the COMPRESSION stroke?
Fill in letter: ____
21. In the illustration above, which is the POWER stroke?
Fill in letter: ___
22. In the illustration above, fuel may be injected during which stroke(s)?
a. A only
b. B only
c. C
d. A and B
23. GASOLINE DIRECT INJECTION does what?
a. Operates at LOWER fuel pressure than PORT EFI systems
b. Operates at HIGHER fuel pressure than PORT EFI systems
c. Operates at MUCH HIGHER pressure than PORT EFI systems
d. Operates at SAME pressure as PORT EFI systems
24. INTAKE VALVES in engines with GDI are more prone to carbon deposit buildup than
those in PORT EFI systems. TRUE or FALSE?
25. A NO-START due to NO FUEL could be caused by ANY of the following EXCEPT:
a. Bad fuel pump
b. Bad fuel pump relay
c. Anti-Theft system fault
d. Bad oxygen sensor
(Answer Key on Next page)
ANSWER KEY
1D, 2A, 3B, 4A, 5C, 6B, 7F, 8I, 9H, 10J, 11G, 12H, 13A, 14B, 15A, 16A,
17D, 18A, 19B, 20B, 21C, 22D, 23C, 24True, 25D
Fuel Injection Topics on AA1Car.com:
Electric Fuel Pumps
Fuel Pump Diagnosis
How To Replace an In-Tank Electric Fuel Pump
Gas Cap Loose?
How Electronic Fuel Injection Works
Air/Fuel Ratios
What Is Gasoline Direct Injection (GDI)?
Toyota Fuel Injection
Troubleshoot Fuel Injectors
Troubleshoot Electronic Fuel Injection & Fuel Pump Diagnosis
How Fuel Injection Affects Emissions
What Is Fuel Trim?
Troubleshoot Hesitation Problems
Troubleshoot Idle Speed Control System
Idle Surge (cause & cure)
Throttle-By-Wire systems (Electronic Throttle Control)
Diagnosing Returnless Electronic Fuel Injection Systems
Intake Valve Deposits in Gasoline Direct Injection Engines
Gasoline Fuel Treatments
Troubleshooting & Cleaning Fuel Injectors
Bad Gasoline Can Cause Performance Problems
Watch Out for Bad Gasoline
Fuel Contamination: What To Do If You Put The WRONG Fuel In Your Car
Fuel Octane Ratings & Recommendations
Fuel Filters
