WS3A General Lab Scope

Explain the operation of the sensor or device using the graph:

(Use arrows at different points, and describe what happens there)

At "A" it shows that engine is running rich and at "B", it shows that the engine is running lean. "C" indicates that ECU adjusted the fuel consumption in that way so that it runs engine rich longer to keep efficient engine performance. In this case engine is running in close loop.

Explain in detail an electrical fault that would make this unit operate incorrectly:

The fault in TPS. IAT MAP and MAF sensors make this unit operate incorrectly

Explain why this condition would cause this unit to malfunction/use mathematical equations to back up your explanation:

These sensors will send wrong signal to the ECU in form of voltage. Some sensors have resistance in them, which changes with temperature and others changes voltage with pressure caused by air flow, thats further change the resistance of the sensors.  

Using the graph draw the patteren that this unit would give with this fault (include the different points as with the previous pattern)

Q.Expalin how this condition would affect the operation of the vehicle?

A.The vehicle may run rich or lean



Use arrows at different points and describe what happens there
At "A" there is a constant voltage in the primary winding and it means the magnetic field is building up. At "B" the circuit is broke up and the there is not voltage during this time period but

Explain in detail an electrical fault that would make this unit operate incorrectly
inadequate power supply, high resistance in primary wiring and secondary wiring and air gap in plug electrodes
Explain why this condition would cause this unit to malfunction/use mathematical equations to back up your explanations.
Because of  high resistance in primary and secondary wiring wouldn't generate enough spark to ignite the air fuel mixture and air gap would also cause inaccurate spark.

Using the graph, draw the pattern that this unit would give with this fault (include the different points as with the previous pattern)


Explain how this condition would affect the operation of the vehicle?
Not proper combustion in the cylinders. The engine will give the piking sound, low engine performance, high emissions.

(use arrrows at different points and describe what happens there)
It is switch type of TPS and after around every one second it closed down and in next second it opens again. At "A" it is opened and at "B'' it is closed.

Explain in detail an electrical fault that would make this unit operate incorrectly
Even it will open and close with help of air pressure but if there is and electric fault in it, It will send the wrong signal to ECU. ECU will process and send the wrong signal toward actuators, which will effect the engine performance.
Explain why this condition would cause this unit to malfunction/use mathematical equation to back up your explanation
It will send the wrong signal in form of voltage and the voltage changes in it by movement of the throttle.

Using the graph, draw the pattern that this unit would give with this fault (include the different points as with the previous pattern)

Explain how this condition would affect the operation of the vehicle?
The engine will either run rich or lean depending upon in the voltage that ECU receive.

(use arrows at different points and describe what happens there)
At "A" the maximum air going through MAF and at "B" the minimum amount of air going through the sensor. At "C" and "D" when there the very low amount of air going through the MAF before next flux of air going through it.

Explain in detail an electrical fault that would make this unit operate incorrectly
Incorrectly operation of MAF will send the wrong signal about how much air is going in through it and thus ECU will process it incorrectly that how much air is needed to run the engine efficiently.
Explain why this condition would cause this unit to malfunction/use mathematical equation to back up your explanation:
The signal is sent to ECU in voltage form and MAF changes it voltage according to how much air is going through it.
Using the graph, draw the pattern that this unit would give this fault (include the different points as with the previous pattern)

Explain how this condition would affect the operation of the vehicle?
The engine will run out of order in terms of rich and lean condition

Explain the operation of the sensor or device using the graph;
(use arrows at different points and decribe what happens there)
There is a crankhaft sensor over the fly wheel. It has number of teeths on fly wheel and a hole for TDC. When the pully rotates, the sensor senses the lots of teeth and groves in it. It then send the voltage changes by this to ECU

Explain the operation of the sensor or device using the graph:
IAT sensor is a NTC. At high temperature the resistance is low and hence increased voltage. In above graph the temperature of coolant increasing which makes the sensor resistance lower and cause increased voltage at its terminals.

Explain the operation of the sensor or device using the graph:
(use arrows at different point and describe what happens there):
MAP sensor here is changing its voltage as the pressure or vacuum in changes in the manifold. Voltage is high when there is more vacumm in the manifold and low when  there is low vacuum in it.

Explain the operation of the sensor or device using the graph:
The above graph shows that the engine is running in close loop. It means that engine is warmed up. The point in graph where it touched the highest voltage shows that the engine is condition is rich and lowest point shows that it is lean.