All Possible Stuff

Question 1

The process of converting an analog signal to a digital signal is referred to as what

Answer 1

Encoding

Question 2

A protocol is a common language for data communication between control modules. What are common protocols used in heavy duty vehicles

Answer 2

SAE J1587, J1708 and J1939

Question 3

A linear type databus may have a resistor on either end. How many ohms would that resistor be.

Answer 3

120 0HMS

Question 4

A throttle position sensor is also called TPS. A TPS is also a …..

Answer 4

Potentiometer

It has three wires. Reference voltage signal and ground. The higher the voltage the faster you go

Question 5

If an ECM notices a signal voltage drop of 5 V DC in a temperature sensor circuit, What will the ECM do

Answer 5

The ECM will make the decision that an electrical open has occurred in the sensor circuit and create an active code indicating the sensor circuit voltage is high. It should be reading less than 5 V returning to ECM after it goes through the sensor

Question 6

What type of connector would allow you to communicate with the ECM on highway and off road equipment

Answer 6

A DDL. Diagnostic data link

Question 7

In an EUI pre-injection, the fuel injector Cam lobes starts to force the fuel injector plunger down and what three things are happening

Answer 7

The solenoid is de-energized, the poppet valve is open and fuel is forced out of the injector by the plunger into the fuel supply passage, not the nozzle tip

Question 8

During EUI Injection The cam lobe continues to force the injector plunger downward and injection can begin at any time. During injection what four things are happening

Answer 8

The solenoid is energized, the poppet valve is closed, injection nozzle is open and fuel is injected into the cylinder

Question 9

The open end of a wrist pin snap ring should point to the _____ of the piston.

Answer 9

Bottom

Question 10

What are the common piston oversizes?

Answer 10

Imperial: .010 .020 .030
Metric: 0.25, 0.50, 0.75 mm

Question 11

Diesel fuel is a hydrocarbon composed of 85% ____ and 15% ____.

Answer 11

85% carbon and 15% hydrogen

Question 12

What does a diesel engine require for complete combustion?

Answer 12

Sufficient air, correct amount of fuel and sufficient heat for ignition.

Question 13

Injector lines are made of what?

Answer 13

Heavy wall seamless steel tubing

Question 14

On an inline injection pump, what are the injectors required to do?

Answer 14

Atomize and distribute the fuel in the cylinder

Question 15

What is RAM?

Answer 15

Random Access Memory

Question 16

What is EEPROM?

Answer 16

Electronically Erasable Programmable Read Only Memory

Question 17

On a temperature sensor, an open causes a ____ voltage code and a short causes a ____ voltage code.

Answer 17

Open causes a high voltage code

Short causes a low voltage code

Question 18

Why should you not touch an electric injector harness or connections with the engine running?

Answer 18

There is high voltage present which can cause a serious shock and personal injury

Question 19

Active regens require what to be injected into the exhaust stream?

Answer 19

Hydrocarbons

Question 20

An active regen can be initiated by:

Answer 20

• The ECM during a driving cycle
• a DPF dash switch
• Diagnostic program

Question 21

What happens when DPF soot loading reaches 80%?

Answer 21

• DPF light continues to flash
• Check engine light comes on
• Engine begins to de-rate

Question 22

The HEST light illuminates when exhaust temps reach _____ and vehicle speed is less than ____.

Answer 22

450C or 842F

8 km/h or 5 mph

Question 23

The DEF level reaches 0%, the stop engine lamp illuminates, engine is further de-rated and max vehicle speed is limited to ____.

Answer 23

8 km/h or 5 mph

Question 24

The EGR reduces what emissions?

Answer 24

NOx

Question 25

Define as the resistance of fluid to flow is?

Answer 25

viscosity

Question 26

Two types of head gaskets are:

Answer 26

steel

composition

Question 27

Two common valve face angles are:

Answer 27

30 and 45 degree

Question 28

Identify the 2 types of exhaust brakes.

Answer 28

sliding vane type

butterfly type

Question 29

RAM random access memory is a notepad. Describe it

Answer 29

Information or values from input sensors can be retrieved from and entered into ram. CPU uses ram when performing calculations. Ram is volatile. Whenever power is lost or disconnected the information in ram is lost

Question 30

What is the percentage number of Solid Steam Valve Heat Transfer

Answer 30

75% of the cooling of a solid stem valve occurs between the VALVE FACE and the VALVE SEAT and 25% is transfer from the VALVE STEM to the VALVE GUIDE.

Question 31

What is the percentage number of SODIUM-COOLED Steam Valve Heat Transfer

Answer 31

50% of the heat is from valve stem to the valve guide and this results in additional cooling