ASE Practice Test (A1: Engine Repair)
The cylinder head's surface has just been machined. What will have to do to the valve train?
Correct answer: Grinding the valve stems
Grinding the valve stems will have to be done because the distance has been reduced between the rocker and the pushrod, so you grind the valve stem to compensate.
A cylinder leakage test is used to diagnose an engine miss. Technician X says that any cylinder with over 20 percent leakage has excessive leakage. Technician Y says that air leaking from the tailpipe indicates a cracked cylinder head. Who is right?
Correct answer: X only
If cylinder leakage exceeds 20 percent, check for air escaping from the tailpipe, the positive crankcase ventilation (PVC) valve opening in the rocker arm cover, and the top of the throttle body or carburetor.
The engine is making a rattling noise, according to a client. It's coming from the drive belt/serpentine belt system, according to Technician A. The following step is to:
Correct answer: Inspect the pulleys for signs of excess play or bearing noise
The rattling sound is most likely coming from a loose pulley or a failing bearing inside the pulley. The belt would not make the rattling noise, and the part at fault must be located before anything is replaced.
Which of the following causes a flapping noise near the front of the engine?
Correct answer: Timing belt tension too loose
A loose timing belt will cause a flapping sound near the front of the engine.
When the engine is cold, an engine noise sounds like a knock on the side of the engine. When the engine achieves operational temperature, the noise goes gone or is lessened. Which of the following is the MOST LIKELY reason for the problem?
Correct answer: Piston Slap
Piston slap is a knock heard at the side of the engine which is louder when the engine is cold and goes away or is reduced when the engine reaches operating temperature.
An idle vacuum test is carried out by a technician. The 2001 Sedan's test results show a pressure of 11 in. Hg. What should the technician check next?
Correct answer: Check for proper timing
Sticking valves, weak valve springs, and exhaust restrictions would cause a fluctuating vacuum. Exhaust restrictions would need to be tested for separately and by testing for vacuum with accelerating, not at idle.
While cleaning the pleated paper-type air filter element, the air gun should be held:
Correct answer: Away from the inside of the air filter element.
When cleaning a pleated paper-type air filter element using compressed air, hold the air gun tip about 6 inches (152mm) from the inside of the filter element.
When doing an engine compression test, you must disable the fuel injection, ignition systems and all of the following reasons, except:
Correct answer: Prevents inaccurate readings
While all of these are valid reasons for disconnecting the ignition and fuel injection systems, you need to think about safety first. Accurate measurements are important, but that wasn’t the basis of the question.
A power balance test is being performed on an engine. Technician X says to note the engine RPM before and during the test for each cylinder. Technician Y says to record the RPM drop for each cylinder. Who is right?
Correct answer: Both X and Y
Both technicians are correct. Tech X is right because engine RPM (Revolutions Per Minute) is an indicator of when that cylinder is contributing to the engine power and if it is balanced. You note the RPM before and during the test so when the cylinder is shorted out you can tell if it changes. Tech Y is right because when the engine speed (RPM) does not drop or change, then that cylinder is not having an effect on engine operation or balance.
An air leak within the cylinder is what you're searching for when performing an engine compression test. This test will reveal air leaks in all of the following, with the exception of which?
Correct answer: PCV valve
An engine compression test will find air leakage from the intake or exhaust valves, piston rings, and or the cylinder head gasket. While it can detect a loss through any combination of those components, it will only detect a leak in those components.
What might happen if new rings are installed without removing the ring ridge?
Correct answer: The piston ring or top compression ring may crack or break
Failing to remove the ridge ring may cause piston ring lands and/or the top compression ring to crack or break after the engine is assembled and started.
Technician X says the closed coil end of a valve spring should go against the cylinder head. Technician Y says all valve springs use shims to control free spring height. Who is right?
Correct answer: X only
Technician X is a correct. A closed coil end of a valve spring should go against the cylinder head. Technician Y is wrong because all valve springs do not use shims to control assembled height. It is also wrong because it should state assembled height.
Technician X says old antifreeze may cause corrosion build-up in the cooling system. Technician Y says some original equipment manufacturers (OEM) recommend that the coolant be changed at specified intervals. Who is right?
Correct answer: Both X and Y
Both technicians are correct. Antifreeze or engine coolant contains corrosion inhibitor that wears out over time, so this is the reason it is recommended that the coolant be replaced and the system flushed at a service interval. The freeze protection of the coolant never changes.
A customer complains about white smoke coming from the exhaust system. You should start by checking which system for low fluid levels?
Correct answer: Cooling system
Engine oil leaking into the combustion chamber would cause smoke with a blue tint. Transmission fluid and brake fluid wouldn’t find their way into the engine and be expelled through the exhaust. Coolant creates a white smoke that can leak into the cylinder when a head gasket has failed.
Technician X says a special puller and installer tool is required to remove and install the vibration damper. Technician Y says that if the intertia ring on the vibration damper is loose, the damper must be replaced. Who is right?
Correct answer: Both X and Y
Technician X is correct in stating that a special puller and installer tool are required to remove and install the vibration damper. Using a regular gear puller to remove the vibration damper willd amage the damper. Technician Y is correct in stating that a loose intertia ring on the damper requires replacement of the damper.
When adjusting valve lash on engines with overhead camshaft cylinder heads, all of the following statements are correct, EXCEPT:
Correct answer: The engine must be cold for all engine manufacturers
You must check the specific OEM procedure for adjusting valves either hot or cold.
In the illustration, what engine seal is shown?
Correct answer: Valve
A valve seal is shown in the picture.
Which components inside the valve train are most likely to create a significant amount of excess engine noise?
Correct answer: Worn or dirty rocker arms
There are many small moving components inside the valve train that can cause noise. However, out of the listed answers, only the rocker arms are actually located inside the valvetrain.
When pressing the wrist pin into the piston and connecting rods, which of the following steps is the technician LEAST likely to perform?
Correct answer: Heat the wrist pin
Heating the wrist pin is a step LEAST likely performed by the technician. Heating the wrist pin will cause it to expand and prevent it from fitting into the connecting rod and piston bores.
Below are the following ways the piston is attached to the rod, EXCEPT:
Correct answer: Woodruff key
Woodruff key is not included when piston is attached to the rod.
A technician is testing the ECT (Electronic Controlled Throttle) circuit with a stored DTC P1121 on a laptop computer with manufacturer software (Electric Throttle Control Actuator). Which of the following customer complaints might be caused by a defective ECT return spring malfunction?
Correct answer: Low power
The ECM has a stored DTC P1121 (Electric Throttle Control Actuator). When the malfunction is detected, ECM enters fail-safe mode and the MIL lights up. While the engine is in fail-safe mode and malfunction A of DTC P1121 is detected, the engine speed will not rise more than 2,000 RPM and thus cause a low power complaint. The ECM controls the electric throttle actuator by regulating the throttle opening around the idle position.
A customer complains that their engine isn't producing enough power. It was an sudden change. The technician notices that the engine coolant is low and that there is white smoke coming from the exhaust during the check. Which of the following best describes the situation?
Correct answer: Cracked cylinder wall
Cracks in the cylinder walls are one of the most common forms of engine block damage, particularly in large engines and sports cars. These cracks can allow water pockets to leak coolant into the cylinder. This may cause running issues, as well as a white smoke that shows expelling from the exhaust.
Technician X says before you remove an engine assembly, the battery must be disconnected. Technician Y says to assist in reassembly, you should take a photograph of the engine compartment before you remove any components or connectors. Who is right?
Correct answer: Both X and Y
Both technicians are correct. Before you remove an engine assembly, the battery must be disconnected. And to assist in reassembly, you should take a photograph of the engine compartment before you remove any components or connectors.
The noise fades while a cylinder is being evaluated during the cylinder balancing test, and the engine makes a knocking sound that changes with RPM. Which of the following could be the root of the problem?
Correct answer: Rod bearing
A bad rod bearing will make a knocking sound with changes in RPM and disappear when the cylinder is shorted out.
Which of the following is the best diagnostic approach for identifying if a fuel injector is defective without having the manufacturer electrical specifications?
Correct answer: Determine if all injectors have the same electrical resistance
While it is always best to compare electrical readings to manufacture specifications, a fuel injector that tests far above or below the others is likely to be faulty. Further testing can then be done to verify diagnostics before making a repair.
Which of the following processes is NOT necessary when refilling a cooling system?
Correct answer: Mixing tap water and distilled water
Distilled water is the least likely required in a cooling system because it has no effect on the cooling ability of the solution. Distilled water is not required in a cooling system. It is used with battery electrolyte.
Technician X says the voltage required maintaining spark is referred to as the spark line and the duration of the spark line is based on total primary circuit resistance and coil voltage available. Technician Y says problems with the burning (called fuel propagation) will show up within the spark line. Who is right?
Correct answer: Y only
Technician Y is correct because problems with the fuel/air burning (called fuel propagation) will show up within the spark line. Technician X is wrong because the voltage required maintaining spark is referred to as the spark line and the duration of the spark line is based on total secondary circuit resistance (not primary circuit resistance) and coil voltage available. A typical firing voltage for a DI system is 8-10 kilovolts (kv). The spark line, which indicates the amount of time current flows across the spark plug gap, should also be smooth and level. Normal current flow usually lasts 1.2-2 milliseconds. Short or uneven spark lines, like high-firing voltages, indicate high secondary circuit resistance.
You run a cylinder compression test and get a zero compression rating along with a lot of engine blowby. Which of the following is indicated by this?
Correct answer: A hole in a piston
A hole in a piston causes several symptoms that will show up. Piston failure often results in engine noise such as a rattling or knocking during idle. It might also lead to oil burning, loss of power and misfiring.
Which of the following showed that the cooling system is contaminated?
Correct answer: ATF (automatic transmission fluid) in the coolant
ATF (automatic transmission fluid) in the coolant indicates contaminated.
What should you do first when attempting to diagnose coolant consumption?
Correct answer: Perform a cooling system pressure test
The cooling system pressure test reveals the cause of the leak. It does this by pressurizing the cooling system just as it would if it were operating under normal conditions. There’s no need to visually look for the leaks prior to this test.
