WS8

Primary & Secondary Ignition Patterns

WS8 Primary & Secondary Ignition Pattren
Make & Model : Toyota 4A - FE engine

Firing voltage : The voltage needed to push the spark jumps to the spark plug gap.

Burn voltage : The voltage needed to maintain the ARC between the spark plug electrodes to burn all the fuel in the combustion chamber.

Burn time : The length of time during which the ARC is maintained between the spark plug electrodes.

Normally used to check the secondary circuit components.Like  spark plugs , HT leads , secondary ignition coil, distributor cap,rotor and king lead.

Dwell time : The length of time during which the primary circuit is grounded,turned on before each cylinder firing so that it can build strong enough magnetic field.The secondary winding can create a strong enough spark to jump the spark plug gap .

Primary Ignition Pattern : It's a very good way to check our primary circuit.Also to see firing voltage and burn time.The higher the firing voltage the shorter the burn time is.This uses string theory so as the firing voltage decrease our burn time increases.

Secondary Ignition Pattern : This pettern is a reflection of the primary ignition.It has the same characteristic.The produced by the primary circuit collapsing on itself inducing a voltage very similar to the primary pattern.But the firing voltage is lower. After a snap acceleration, we can see the firing voltage decreases and burns the time that increases which proves the string theory.

In the illustration shown, the horizontal voltage line (primary Sparkline) in the centre of the oscilloscope is at fairly constant voltage of approximately 24 volts, which then drops sharply into what is referred to as the Coil Oscillations. The length of the afore mentioned line is the ‘Spark Duration’ or ‘Burn Time’, which in this particular case is 1.25 ms
The high vertical line at the center of the trace is over 257 volts, this is called the 'induced voltage'.
All these sections of the primary trace are also illustration in individual waveforms listed in the menu. The coil’s High Tension (HT) output will be proportional to the induced voltage. The height of the induced voltage is sometimes referred to as the primary peak volts
A low (0 - 50) voltage scale is required to observe the sparkline and the coil oscillation, while a higher voltage of 0 - 400 volts will require the to check the induced voltage.

Secondary Voltage Patterns

The waveform is an individual secondary High Tension which is the HT picture,that shows one cylinder at a time. This secondary waveform shows the initial voltage.It jumps up to the plug gap, known as the Plug Kv after it shows the length of time that the HT is flowing across the spark plugs and electrode plug gap. This period is known as Burn Time or the Spark Duration.
In the illustration above it can be seen as the horziontal voltage line,Sparkline in the centre of the oscilloscope is at fairly constant voltage.Approximately 5 Kilo volts Kv, which then drops sharply into Coil Oscillations.
The coil Oscillation should display a minimum number of peaks.Both upper and lower is a minimum of 4 - 5 should be seen. A loss of peaks on this Oscillation shows that the coil needs substituting.
The period between the coil oscillation drops down its when the coil is at rest and there is no voltage in the secondary coils.
The drop down is referred to as the Polarity Peak,produces a small Oscillation in the opposite direction.The plug fires voltage.This is due to the initial switching on of the coil’s primary current point.
The voltage within the coil is only released at the correct point of ignition and the HT spark ignites the air and fuel mixture.

Shorted Secondary

 As the cylinder 4 has been grounded to the body the firing voltage decreases because it does not need as much voltage as in a sprark plug but this causes the burn time to increase

 spark tester

  The gap in the tester is smaller than the spark plug gap then firing voltage has decreased , the burn time has increased.

WS7

Make peugeot 
Model 306xRI
Year 1994


CO means..Carbon monoxide is a indicator of rich air/fuel mixture and shows there is not enough oxygen in the combustion chamber


HC means..Hydro carbon levels show the amount of unburnt or partly burnt particals in the exhaust. misfire due excessive lean and also rich air/fuel ratio.The lower the levels of HC the more efficent the fuel is being burnt in the combustion chamber.

CO2 means..Carbon dioxide is a good by product and indicates good combustion inside the engine and is produced when the fuel is oxidised , a good rule is the higher the CO2 level the more efficient the engine works .

O2 means..high levels of oxygen is a good indication of lean air/fuel mixture because O2 increases as the air/fuel mixture gets leaner , it also can indicate misfire.

Co=0.416% HC=132ppm CO2=13.80% O2=1.16%

The combustion of air fuel mixture is normal. CO2 is a little bit higher but still within acceptable clean emissioni CO2 limit. The engine is running at acceptable emission level because of low CO and O2. But the engine is running  a bit on the rich side and small amount of air fuel mixture is unburned this results in slightly higher HC level. This could also be due to the catalyst converter is not working at cold idle, so reading bad exhaust gases. 


CO=0.650% HC=162ppm CO2=14.08% O2=0.55%

The four reading show the engine running at efficient and idle. Good combustion was take place in the cylinder and exhaust low emission gas as all of four gases are within the parameter of clean emission standard. At this stage, the catalyst converter should start working as the engine is warmed up. air fuel ratio and most of the fuel mixture is burnt.
CO=1.210% HC=115 CO2ppm 13.88% 02=0.36%

The HC is lower  than warm idle, due to the engine need more fuel to run at high speed. The engine is running at cruising with no load, due to the CO is low. The CO2 and O2 represent the combustion is good and most of air fuel mixture is burnt .
CO=4.485% HC268ppm C02=11.97% O2=0.37%

The HC and CO are high to tell us the air fuel mixture is rich, due to the combustion is incomplete, so large amount of air fuel mixture was found in the exhaust gas. CO2 is low to show the combustion is not perfect as large amount of air fuel mixture have not convert into CO2. The O2 is low to show the catalyst converter used up most of the O2 to convert CO into O2, but the CO is too high, so we still read high CO in exhaust gas.
CO=0.487% HC=136ppm CO2=13.96% O2=0.89%

The O2 is a little bit higher. This indicate the oxygen in the exhaust gases is high. This can be caused by lean air fuel mixture. Larger amount of oxygen fail to condense with fuel and cause the fuel is not condense enough, due to it take longer time to burn all the fuel and create more heat and release more NOx. The CO2 is low which means the combustion is incomplete.

Accelerate the engine by blipping the throttle will cause the engine running rich. High HC and CO show the incomplete of burning, due to the ECU will sense low intake vacuum and inject more fuel into the cylinder. The O2 is high that means the high amount of fuel is unburned in the exhaust gas which is cause by a lean mixture. The ECU will sense high intake vacuum and shorter the injector pulse width to make the mixture lean. Low CO2 is also incomplete combustion in the cylinder.

CO=0.493% HC=3004ppm CO2=9.17% O2=7.78%

The ignition misfire will cause high HC and O2 and low CO2, due to one of cylinder is misfire and all of the fuel mixture is unburned into the exhaust gases. The Carbon monoxide is normal, due to the air fuel mixture is normal and no exceed HC. This is not lean misfire because the HC is high and no combustion was taking place in the cylinder.


CO=0.198% HC=337ppm CO2=9.39% O2=7.82%

The cylinder is misfire, due to no fuel inject in the cylinder. The oxygen sensor will sense a lot of oxygen in the exhaust gas and send a signal to ECU to demand more fuel, this cause the exhaust gases read high HC. The O2 is low as there is only three combustion take place.
CO=0.74% HC=181ppm CO2=14.5% O2=0.62%

The HC is getting lower, due to the engine need more power to turn on the air condition and steering wheel. The more fuel inject to give the engine more power to maintain its idle speed. The CO2, CO and O2 are within parameter and complete combustion was taking place in the cylinder. Beside that, the ECU will open more the idle valve to allow more air to flow into the intake manifold to increase the idle speed.
The catalyst converter has Rhodium, Palladium and Platinum that covert HC, NOx and CO into harmless CO2 and H2O. Thus, the vehicle with catalyst converter emit low HC, NOx and CO and the vehicle without catalyst converter emit high level of NOx, HC and CO gases. 
260 degree Celsius is the temperature at which a catalyst conveter start to work and this temperature point is called light off point. At this temperature the catalyst converter is only 50% efficient . The catalyst converter is only 100% efficient when the exhaust temperature reaches 482 degree Celsius to 871 degree Celsius. When the temperature reaches the light off point, the exhaust gas analyzer starts reading the levels of CO, HC and NOx. When the catalyst converter is warming up, the reading of CO, NOx and HC are low, this means the catalyst converter start to convert HC, CO and NOx in to CO2 and H2O.
Zirconium and titanium oxygen sensor usually have 1 to 4 wires. Generally there are three types of oxygen sensor, the oxygen sensor with heat element, the sensor without heat element and wide band oxygen sensor. The heat element sensor has 3 or 4 wires which are power for heater, ground for heater, oxygen output signal and ground for oxygen sensor. The oxygen sensor without heat element has 1 or 2 wires which include ground and another one is output signal. Wide band oxygen sensor has 5 wires and they are power for heater, ground for heater, two sensor signals and one ground wire for both sensors. 

WS6

Oxygen Sensors on Vehicle

1.0 Locate Oxygen Sensor
1.1 Locate an oxygen sensor on your vehicle. Describe where it is
located:

• The oxygen sensors are located directly in the exhaust system, on the left hand side of the engine on the exhaust manifold.
  1.2 How many wires for this oxygen sensor? ……three wires ………
  1.3 Record the colors for each of the wires at the sensor side of the
  connector (not the ECU side of the connector). Then list the use
  of the wires. Usually a black or blue wire will be the O2 sensor
  signal, Grey may be the sensor ground. Heater power and
  ground are often white. But there may be other colors. You may
  have to consult a wiring diagram.
     
  Colour Use or Purpose
  White …Power supply
  

  White ...Signal

  Black … Ground

  
  

  1.4 What type of Oxygen Sensor is this? 

  Zirconia switching sensor

  Broadband Air Fuel Ratio sensor? (one cell) …….

  Broadband Air Fuel Ratio sensor? (two cell) …….

  This worksheet is designed for switching type sensors only. If

  you have a broadband sensor, see your lecturer for another

  worksheet.

  2.0 Back probe the Oxygen Signal Wire with a pin and connect to

  an oscilloscope. If you need help using the oscilloscope see your

  lecturer or other help sources. Check that you are connected to the

  Oxygen sensor signal: Run the engine and check that you are

  seeing a signal. Connected OK? Yes …yes ok……………….

  3.0 Watch and Record Oxygen Signal pattern at 2500 rpm. Let

  the engine warm up and enter closed loop so you see a normal

  cycling pattern. You may have to hold the rpm about 2500 for half a

  minute to go into closed loop.

  3.1 Freeze your pattern and draw or photograph it onto the

  graph below: Note the voltage and time per division or scale

  next to the graph.

  

  
  

  3.2 How high does the voltage go?......0.8V...........

  3.3 How low does the voltage go? ……0.2V……….

  3.4 What is the average voltage? (Some oscilloscopes have

  functions that will calculate the average for you. If not, just

  guess.)……up to 5V………….

  3.5 How many “Cross Counts” does the signal have in 10

  seconds? (One cross count is when it goes from high to low, or

  from low to high.) List here: …7………..

  
  
  

  
  

  The highest voltage I got was 0.85 Volts which was within manufaturer specs. each division is 0.5 Volts and time is 1 second.

  
  

  3.6 If the signal is not cycling normally, describe what the signal

  does:

  The cycling is normal.

  
  

  
  

  4.0 Watch and Record Oxygen Signal pattern at Idle rpm. Let the

  engine warm up and enter closed loop so you see a normal cycling

  pattern. You may have to hold the rpm about 2500 for half a minute

  to go into closed loop. Then let the RPM come down to idle.

  

  
  

  4.2 How high does the voltage go? …0.66V…………

  4.3 How low does the voltage go? ……0.84V………

  4.4 What is the average voltage? (Some oscilloscopes have

  functions that will calculate the average for you. If not, just

  guess.) …0.5V………

  4.5 How many “Cross Counts” does the signal have in 10

  seconds? (One cross count is when it goes from high to low, or

  from low to high.) List here: ……12……

  4.6 If the signal is not cycling normally, describe what the signal

  does:

  Cycling is normal.

  
  

  5.0 Make this Oxygen Sensor go rich by accelerating once or

  twice. (The fuel system should normally make the system go rich

  when you do a sudden acceleration.) Push on the accelerator

  quickly but don’t let the rpm go high enough to hurt the engine.

  (If you act like you will hurt the engine you will be asked to leave

  lab.) The signal should go over 0.85V.

  5.1 Freeze your pattern as it goes rich and draw or photograph

  it onto the graph below: Note the voltage and time per division

  or scale next to the graph.

  

  
  

  
  

  5.2 How high does the Oxygen sensor voltage go? 782V

  5.3 If this signal is not going high normally, describe what the signal

  does:

  The voltage goes high when we do a sudden acceleration, the voltage increasing from  less than 0.2V to higher than 0.8V in less than 100ms.

  
  

  
  

  
  

  6.0 Make this Oxygen Sensor go lean by doing a sudden

  deceleration. Gently run the rpm up to about 3,000, and let the

  RPM drop suddenly. The fuel system should make the system

  go lean on deceleration. The signal should go below 0.2V.

  6.1 Freeze your pattern as it goes rich and draw or photograph

  it onto the graph below: Note the voltage and time per division

  or scale next to the graph.

  
  

  
  
  

  

  
  

  
  

  6.1 How low does the Oxygen sensor voltage go?..0.006V.......

  6.2 If this signal is not going low normally, describe what the signal

  does:

  The voltage goes down when we do a sudden deceleration,this sensor is in good working condition as all the results were within the specifications.

  
  

  
  Measure the Response Time of the sensor. You want to know
  that the sensor can respond quickly to changes in the exhaust gas.
  The best way is to do a sudden acceleration, freeze the pattern, and
  measure how long it took the sensor to go from lean to rich.
  7.1 Freeze your pattern as it goes suddenly rich from a lean
  condition and draw it into the graph below: Normally you want
  the voltage to go from below 0.2V to above 0.8V. in less than
  100 ms. Note the voltage and time per division or scale next to
  the graph.
  7.2
  
  

  

  7.2 Measure how long the sensor took to go from lean to rich.

  Use the cursers on the scope if necessary. Record how long

  the sensor took here: 0.005 volts

  

  
  

  
  
  
  

WS5

Scan Tool Diagnostics

Above are the information we could obtain from this vehicle .

I checked on the scan tool but there were no fault codes recorded .

4. I disconnected the engine coolant temperature sensor.Checked on the scan again. now i found the fault code and recorded in the chart below.

Find What Data Has Changed
5.1 Look through the scan tool data to see what PIDs
(Parameter Identification of system voltages) have changed.
Which readings don’t make sense or don’t read what you
would expect. Concentrate on the PIDs related to the codes.
5.2 Record the PIDs that have changed below

Visual Inspection to find fault
6.1 Do a visual inspection under the hood to find where the
problem is. Use information from the code to know where to
look for the problem and what type of problem to look for.
Describe problem you found
Yes , the Coolant Temperature senor is disconnected.

Repair fault
7.1 Plug back in the connector, or repair problem found
7.2 Describe what you did
Reconnected the the senor 

Recheck Data PIDs
8.1 Recheck the data with the scan tool
8.2 Record the voltages for the PIDs related to the problem, to
confirm they are back to normal

9 Clear Codes
Describe what you did to clear codes:

I cleared the faults code po11 which is the coolant temperature sensor, also the coolant fan referred to normal on/off position automatically where it was full time on when the coolant temperature was disconnected.

Recheck the system for any faults and none were recorded.

Live data is  very useful also easiest ways to find a problem specially if there is no fault codes recorded . It is a good way to check the performance of the vehicle under different conditions where some faults could be hiding.
Parameters are also important  because how would we know if this data we are getting is within the manufacturer specs. we have to compare the live data with the parameters to make sure that they are within the parameteres that is concidered normal for this vehicle .
Scan tool is very helpful to find the problem, it can point us in the direction we need to be looking ... it might not point where the problem is but its a good start for direction and even if the sensor is faulty after checking the circuit for bad connections , bad earth ... by comparing the live reading against the parameters.

WS4

Fuel Pressure and Flow (Petrol only)
Make....Toyota.....
Model..4A-FE...

4. Attach fuel pressure gauge and notice which scale on the gauge you will be using.
Briefly turn key on or start vehicle, then turn it off. Check for fuel leaks.
Are there leaks? Yes .................... No ..no leaks..........
If there are leaks you must correct them and retest before continuing. If you need
help, ask !

5. Measure the fuel pressure with the key on, engine off.
Record it here: ........284kpa................. (also record the units you are using, psi, bar,
Kpa, etc…)


6. Idling: Measure the fuel pressure with the engine idling. Watch the pressure for a
couple of minutes.
Record pressure here: .........260kpa..........................

7. Maximum: With the engine idling, use the special tool to clamp the fuel return line.
Note: this can only be done for a short period.
Record pressure here:………490kpa…………….

8. WOT: With the engine idling, disconnect and plug the vacuum line going to the fuel
pressure regulator.
Record pressure here: ...........310kpa........................

9. Residual: Turn off the engine, and watch the fuel pressure for five minutes.
Record your residual or rest pressure here: .........259kpa.............................

10. Flow:To check the folw of fuel in the fuel lines and to make sure enough fuel is getting to our injectors 2.2 L per minute and also to check if it is within manufacture's specification because too low will cause a lean combustion and too much will make it run rich.

The importance of knowing the  vehicle fuel pressure is because low or high pressure may effect the engine performance. High pressure pushes more fuel in the injectors and makes the engine run rich and low pressure makes it run lean and also tests faulty pressure regulator and whether the fuel pump is working or not and what the pressure of the fuel pump is.

Describe the symptoms a vehicle would give with each case:Low fuel pressure: The engine will run lean and the oxygen sensor will give send the signal to ECU to reduce the amount of air so makes the throttle more close  even there is high demand of air for engine performance

Low fuel flow: The engine will run lean and the oxygen sensor will send the signal to ECU to reduce the amount of air making the throttle closer  even though there is high demand of air for engine performance.

High fuel pressure: High pressure puts more fuel in the injector making engine runs rich and so the oxygen sensor will sense that there is a shortage of air and will send the signal to ECU to send more air in and hence effect the engine performance.

Faulty fuel pressure regulator: Faulty regualtor extra fuel will not return to the tank causing the  fuel to pass through the injectors engine, high HC coming out form the exhauct .With the engine idling, use the special tool to clamp the fuel return line.

Input sensors and Actuators On-car

Make...toyota......

Model......4A-FE......

the voltage to the fuel injector is 14.49v

-We check the voltage supply to the fuel injectors to make sure there is no bad connection, high resistance in the circuit and the injectors circuit are opening or closing.The voltage supply to the injector should be enough to operate, otherwise it can cause the injector by not sparying properly.

-If we find lower voltage at the injectors than at the battery, this could be due to high resistance in the circuit, bad connection. it will effect open time of injectors, unnecessary fuel will enter to the cylinders.

There are two types of (TPS) sensors, one is a switch and another potentiometer or linear resistor type.The throttle position sensor (TPS) is used with feedback carburetion and electronic fuel injection (EFI) to inform the computer about the rate of throttle opening and relative throttle position.

High resistance in the copper wire or poor connection from ECU in the wire could cause problems so that there is not the correct reference voltage at the throttle position sensor. Also ground wires can cause problems, good ground voltage drop reading is usually lower then 0.05v.

Ground at TPS sensor

Ground wire voltage is 0.02V

If we have a bad ground or bad connection at the battery terminal or high resistane on the ground circuit, it can effect the output signal fo the sensor, that's why ground wire is also important.

It could be losing connection at the ground, the pin is not touching properly and problem in wiring.

Throttle Position Sensor return/output:

The reading from the mete is 0.5V (The ignition on)

Half throttle open position reading is 2.4V

Full throttle open position reading is 3.9V

Slowly open the throttle from the closed position to the full open position and the meter reading slowly increase with no sudden jumps or in the signal. ok!

I got the reading from green wire.

A TPS sensor works like a potentiometer, sending voltage signals to the computer to let it know how far the throttle have opened, as the throttle accelerator pedal moved, the signal voltage of the TPS also change. At closed throttle position, the signal of the TPS is low. At the throttle valve opens, the signal voltage increases so, at fully open throttle, the voltage should be less then 5V.

A fault TPS sensor can confuse the ECU causing the idle to be hunting, engine light will be on and hesitate while accelerating.

Throttle Position Switches:

Idle wire: Colour: Black

Volts at idle: 0.08V

Volts apart throttle or open throttle: 10.70V

Wide open throttle wire colour: Black

Volts at idle or part throttle: 10.24V

Volts at open throttle: 0.00V

Because the ECU will be monitoring the voltage signal received from the TPS sensor whcih can determine the fuel delivery required, so at different throttle positions the ECU would act as an injector difference of the fuel, so that the engine is running with a good quality of fuel/ air ratio – lambda which is 14.7:1.

ECT (Engine Coolant Temperature ) Sensor

The reading is 3.59V with the ignition on but not starting engine.

The engine is at normal operating temperature, it was cold and that is the right temperature of the engine.

Start the engine and warm up for about 2 minutes and the voltage of the ECT sensor is 2.67V

Yes, with the cold engine reading is 3.59V and with the warm engine reading is 2.67V.

How an ECT sensor works?

An ECT is device that change resistance as temperature change. There is a thermistor inside the sensor. The ECT( thermistor ) is a negative temperature coefficient sensor which means when the temperature goes up resistance and voltage goes down. The ECT works by changing it's internal resistane according to coolant temperature.

The ECT sensor receives 5V reference  voltage from the ECM. When the engine is cold, the ECT will send a high voltage to ECU, so the ECU makes the injector squirt more fuel into combustion cylinder. when the engine is heat up, the signal voltage from the ECU will be low and ECU will control the injector to shorter and less fuel into cylinder. 

If ECT sends an incorrect voltage for the ECU can cause a lean misfire or even no start on cold engine because ECU will control the injector to spary less fuel into combustion cylinder.

Ground Coolant Temperature Sensor

With starting engine the voltage on the meter is 35.5mv

This voltage 35.5mv tell me a good ground. it is important to measure it because we can see the ground voltage is suitable or not (A good ground will usuall read less than 0.05V. ( some manufacturers say 0.10V).

In this picture ECU ground is not good, the ECT sensor ground connected to ECU, if the ground is not good  the circuit is not complete and there is noly one refrence voltage.

RPM sensor or Crank Position Sensor (CkP)

The reading (AC volts) is 3.7V with the engine idling.

With increase engine RPM TO ABOUT 2500rpm, the reading is 7.2V

The reading (DC volts ) is 0.5V with the engine idling.

With increase engine RPM to about 2500rpm, the reading is 1.2V (DC)

The reading (Hz) is 466.4Hz with the engine idling.

The best showed if the RPM sensor was working HZ

Inductive sensor type of RPM.This type of sensor consists of a permanent magnet and pick up coil. The sensor is mounted close to crankshaft. As the crankshaft move on AC voltage pulse is induced in the pick up coil, the crankshaft rotate faster, more pulse are generated and ECU will determine the speed base on the number of pulse produce. 

I think there is only two functions, AC volt function of multimeter tells us how much voltage it generates for every tip passing the sensor magnetic pick up and Hertz tells us how fast it's rotating, as if speed of the shaft increased it increased frequency of rotation, so it start to rotate faster and get more revolutions per minute.

If the ECU did not receive the correct signal from RPM or Crank sensor, it can cause  short circuit, loose connection and  faulty signal converter.

MAP or MAF sensor

I turned on the ignition but no start the engine and checked the reading with the meter it was 1.83V. With the engine idling the reading was 0.6V.

With short acceleration of the engine the reading was 28.4mV.

Inside MAP sensor there is a silicon chip which changes resistance with different pressure inside intake system and this changes output voltage to ECU. When the engine is going hard, intake vacuum drops as the throttle open wide and the engine sucks more air, which requires more fuel to keep the air/fuel ratio in balance.

The readings are correct for the engine, due to the MAP delivered the voltage signal to ECU about 0.6 when the engine at idle. If the silicon chip is damaged, poor connection can effect the output voltage and send the wrong signal to ECU and also the vacuum hose attached to the sensor should be in good condition.

Incorrect signal from the MAP sensor sends the wrong signal to the computer can disrupt fuel consumption and affect engine performance.

IAT (Intake air Temperature), ACT (Air change temperature), or MAP (manifold air temperature sensor

The reading was 12.3 with the igniton "on"

This  reading is more than the reading i had for the ECT

This shows us the IAT sensor is colder than the ECT sensor

The intake air temperature sensor let  the computer know how hot or cold the incoming air is. The computer will then adjust the amount of fuel being injected, as well as make minor adjustments to timing based on that reading.Most air temperature sensors are negative temperature coefficient thermistor with high resistance the they are cold,but the resistance will drop as they heat up.

IAT reading will affect the ECU outputs for fuel injection depending on the intake air temperature as the engine heat up incoming air.The incorrect input can affect the computer sending that incoming air is warmer or colder than it  is , causing it to inject more fuel and advance the timing a tad.

If the air temperature is cold, the resistance in the sensor should be high and the voltage drops across the resistance is high then this voltage will send to ECU and the ECU will control fuel injector delivered more fuel into combustion cylinder. As the temperature is hot, the resistance should be low and ECU will control fuel injector delivered less fuel into combustion cylinder.

poor electrical connections at the sensor. A loose or corroded wiring connector can affect the sensor’s output and create the incorrect temperature and send the wrong signal to ECU.

Camshaft Position Sensor (CMP)

The readings in the different settings

DC volts:124.2mv

AC volts:1.543V 

HZ volts:24.32 Hz

% Duty cycle:82.3%

The AC voltage is good to show the CMP, due to the camshaft position sensor (inductive type) which generates AC voltage.AC voltage will move between 0.3-1 AC voltage, AC voltage increases will engine RPM, so the faster the engine crank, the higher the AC voltage.