Ase Practice Engine Performance

A misfire is detected at the #3 cylinder of a COP ignition system. There is no power at the Bat+ terminal of the coil. Which of the following is the MOST likely cause of this condition?

• Resistance in the primary circuit
• An open between the coil and power source
• A leak in secondary insualation
• Resistance in the secondary circuit

Technician A says a (TPI) throttle position sensor is a potentiometer that indicates throttle angle. Technician B says a throttle position sensor can be tested for resistance with an ohmmeter. Who is correct?

• Tech A
• Tech B
• Both
• Neither

After performing a wet compression test, the pressure in each of the cylinders increased, but remained below specifications. Tech A says this is caused by incorrect valve timing. Tech B says this is caused by worn piston rings. Who is correct?

• TECH A

• TECH B

• BOTH A and B

• NEITHER

A vacuum gauge is connected to a port on the intake manifold of an engine with poor performance. The needle on the gauge fluctuates between 15 ''hg and 20 ''hg vacuum at idle. This vacuum gauge reading indicates...

• a normal condition

• late ignition valve or timing

• a burned exhaust valve

• a restricted exhaust

The PCM uses all of these inputs to calculate air flow ratio and speed control EXCEPT...

• An engine coolant temperature sensor (ECT

• An exhaust gas recirculation valve (EGR

• An intake air temperature sensor (AIT

• A throttle position sensor (TPS

Two techs are discussing a turbocharged engine. Tech A says the wastegate is a component used to control boost pressure. Tech B says when opened, the wastegate diverts exhaust gas from the turbine wheel. Who is correct?

• Tech A

• Tech B

• Both A and B

• Neither

Tech A says when the vacuum hose is disconnected from the vacuum operated fuel pressure regulator, fuel pressure should increase. Tech B says a restricted fuel return line will cause low fuel rail pressure. Who is correct?

• TECH A

• TECH B

• BOTH A AND B

• NEITHER

The MAP sensor's vacuum hose is loose and cracking. Technician A says this sensor measures air mass to establish the fuel injector's base pulse width. Technician B says this sensor measures changes in intake manifold pressure. Who is correct?

• Tech A
• Tech B
• Both
• Neither

A cylinder power balance test is being performed on a vehicle with sequential port fuel injection. Two adjacent cylinders are under performing. Technician A says this could be caused by a restriction in the fuel injectors. Technician B says this could be caused by leaking secondary insulation. Who is correct?

• Tech A
• Tech B
• Both A and B
• Neither A or B

Technician A says the MAP sensor is located on the intake manifold and informs the PCM of intake manifold pressure. Technician B says the MAF sensor senses air flow in the air tube. It's signal indicates engine load to the PCM. Who is correct?

• Tech A
• Tech B
• Both A and B
• Neither A or B