Saturday 25 June 2011
Friday 24 June 2011
WS3 General lab Scope
WS3 General lab Scope
We did this exercise on Toyota engine model 1ZZ
1.
Signal Name RPM (AC magnetic crank or distributor)
Volt/division/range 5V
Time/division/range 1mS
This is an alternating current waveform. At point A, the flywheel teeth moving toward the inductive crankshaft sensor and induce a positive voltage. At point B, the flywheel teeth is align with the inductive crankshaft sensor, thus the voltage drop down to 0V. At point C, the flywheel teeth is leaving the crankshaft sensor and induce s negative.
2.
Signal Name Oxygen Sensor
Volt/division/range 0.5V
Time/division/range 1S
This vehicle has a zirconla oxygen sensor. At point A, the oxygen sensor generate about 0.1V due to the oxygen level is high in the exhaust and did not combine with the fuel, this mean the air fuel mixture is lean. At point B, the voltage signal is about 0.9V, this mean there is a little unburned oxygen in the exhaust and air fuel mixture is rich.
With of close loop system, the oxygen sensor will generate waveform signal. This is due to the ECU will analyze the combustion process and emissions. Therefore, when ECU receive a lean signal (point A low voltage) from oxygen senor, it rich the fuel mixture and the oxygen sensor output voltage will do up to point B. At point B, oxygen sensor sense the mixture too rich and tell the ECU inject less fuel. This action keep continually to adjust the engine fueling and we have waveform signal.
3.
Signal Name Injector petrol
Volt/division/range 20V
Time/division/range 5mS
At point A, the injector is off, so we have supply voltage 12V. When the transistor receive the signal from the ECU and ground the injector or switch on the injector, the available voltage become 0V (negative trigger switch On), this action show at point B. When the ECU turn off the injector, magnetic field in the solenoid collapse and generate back EMF, this is show at point C. At point D show the peak voltage of the back EMF. Point E describe a supply voltage and the injector is in Off position. Point B also show the pulse width and period of an injector switch on ore grounded.
4.
Signal Name Ignition timing control
Volt/division/range 2V
Time/division/range 2mS
Ignition timing control is design to control the spark timing by sending out PWN signal to the ignition system to switch on and off the power transistor. At point A, this is 5V digital signal send from the ECU to the ignition system and activate or saturate the power transistor, then the primary coil is buiding up the magnetic field. At point B, these is no voltage signal send to ignition system, so the power transistor cut off, magnetic field surround the primary coil collapse and induced high voltage into secondary winding and create a spark to ignite the compressed air fuel mixture
1.
Signal Name RPM (AC magnetic crank or distributor)
Volt/division/range 5V
Time/division/range 1mS
This is an alternating current waveform. At point A, the flywheel teeth moving toward the inductive crankshaft sensor and induce a positive voltage. At point B, the flywheel teeth is align with the inductive crankshaft sensor, thus the voltage drop down to 0V. At point C, the flywheel teeth is leaving the crankshaft sensor and induce s negative.
2.
Signal Name Oxygen Sensor
Volt/division/range 0.5V
Time/division/range 1S
This vehicle has a zirconla oxygen sensor. At point A, the oxygen sensor generate about 0.1V due to the oxygen level is high in the exhaust and did not combine with the fuel, this mean the air fuel mixture is lean. At point B, the voltage signal is about 0.9V, this mean there is a little unburned oxygen in the exhaust and air fuel mixture is rich.
With of close loop system, the oxygen sensor will generate waveform signal. This is due to the ECU will analyze the combustion process and emissions. Therefore, when ECU receive a lean signal (point A low voltage) from oxygen senor, it rich the fuel mixture and the oxygen sensor output voltage will do up to point B. At point B, oxygen sensor sense the mixture too rich and tell the ECU inject less fuel. This action keep continually to adjust the engine fueling and we have waveform signal.
3.
Signal Name Injector petrol
Volt/division/range 20V
Time/division/range 5mS
At point A, the injector is off, so we have supply voltage 12V. When the transistor receive the signal from the ECU and ground the injector or switch on the injector, the available voltage become 0V (negative trigger switch On), this action show at point B. When the ECU turn off the injector, magnetic field in the solenoid collapse and generate back EMF, this is show at point C. At point D show the peak voltage of the back EMF. Point E describe a supply voltage and the injector is in Off position. Point B also show the pulse width and period of an injector switch on ore grounded.
4.
Signal Name Ignition timing control
Volt/division/range 2V
Time/division/range 2mS
Ignition timing control is design to control the spark timing by sending out PWN signal to the ignition system to switch on and off the power transistor. At point A, this is 5V digital signal send from the ECU to the ignition system and activate or saturate the power transistor, then the primary coil is buiding up the magnetic field. At point B, these is no voltage signal send to ignition system, so the power transistor cut off, magnetic field surround the primary coil collapse and induced high voltage into secondary winding and create a spark to ignite the compressed air fuel mixture
WS1 petrol fuel injector testing
WS1 petrol fuel injector testing
used a screw driver and the injector was OK. The battery voltage was 12v
Results:
Cyl1 12.2v
Cyl2 12.4v
Cyl3 12.3v
When using a LED tester all flashes were acceptable on idle. When revved flashes got so fast it seemed like the LED tester was perminately on but it wasn't. Testing injectors with a LEd tester is a good test but it isnt accurate enough. All it tell us is its opening and closing thats all, not for how long which is what we're looking for.
When using the multimeter set to duty cycle all 3 cylinders were 2%. The means they were open for 2%. This means they were open for 2% when idling. When accelerated short fast throttle opening it increased to 13.9% meaning 13.9% of one cycle it was open for 13.9%
When using the multi meter to read Hz (hertz) on idle it recorded 0.045k Hz. When increased engine RPM it recorded 1.12k Hz
Calculation: Pulse width ms = (% duty cycle/100) / Frequency
(2/100 / .05 = .02 / 0.05 = .4ms
(1.9/100 / 0.0045 = .019 / .0045 = .42ms
When revved = (13.9 / 100) /.05= 2.78ms. (all 3 cylinders were the same)
CONCLUSION:
I think this is a good way to test injectors without pulling them right out. Doing all these tests you get a good estimation how well your injectors are working. If you get reading out of spec you can guess there maybe a bad connection somewhere. But pulling them out is also a good idea so you can put them on the pattern tester and see how well its spraying because you need good atomised spray not dribbles or uneven spraying. Atomised spray will give you a better combustion (bang) in the chamber than uneven spray or dribbles.
Results:
Cyl1 12.2v
Cyl2 12.4v
Cyl3 12.3v
When using a LED tester all flashes were acceptable on idle. When revved flashes got so fast it seemed like the LED tester was perminately on but it wasn't. Testing injectors with a LEd tester is a good test but it isnt accurate enough. All it tell us is its opening and closing thats all, not for how long which is what we're looking for.
When using the multimeter set to duty cycle all 3 cylinders were 2%. The means they were open for 2%. This means they were open for 2% when idling. When accelerated short fast throttle opening it increased to 13.9% meaning 13.9% of one cycle it was open for 13.9%
When using the multi meter to read Hz (hertz) on idle it recorded 0.045k Hz. When increased engine RPM it recorded 1.12k Hz
Calculation: Pulse width ms = (% duty cycle/100) / Frequency
(2/100 / .05 = .02 / 0.05 = .4ms
(1.9/100 / 0.0045 = .019 / .0045 = .42ms
When revved = (13.9 / 100) /.05= 2.78ms. (all 3 cylinders were the same)
CONCLUSION:
I think this is a good way to test injectors without pulling them right out. Doing all these tests you get a good estimation how well your injectors are working. If you get reading out of spec you can guess there maybe a bad connection somewhere. But pulling them out is also a good idea so you can put them on the pattern tester and see how well its spraying because you need good atomised spray not dribbles or uneven spraying. Atomised spray will give you a better combustion (bang) in the chamber than uneven spray or dribbles.
WS2 Flash Code
WS2 Flash Code
First thing we checked that the engine light is working by turning on the key, the ignition to be switched on, then start the engine and the light is off, that mean the engine is running at most efficient condition. If the engine is still On and flashing, that mean there is fault in the engine.
Second We turned off the key and connect the wire from TE1 to E1 then we turned on the ignition key and the engine light is flashing. Record how many flash you see. For example: it flash once then pause then flash another six times, it means 16. After previous step, looking for diagnostic fault codes sheet then you can see which system is faults.
First thing, we have a visual inspection on the engine and then we look on MAP. ECT, TPS. IAT sensor to fine any physical damage, corrosion, broken wire, leak hose, and bad connection. Another way, wires shorted to other wires or earth. or mechanical problems that will cause an electrical code. After that, we found they are not plug properly. If they are connected properly, we can use an oscilloscope to read the pattern signal from these sensor.
Repair fault:
To repair, we plugged these sensor connector back and start the engine to make sure the engine run properly.
5
Usually, after we fixed or replaced these faulty sensor. The engine light will stop flashing. However, there is another way to clear code by pulling the EFI fuse to clear code from memory or we can use the scan tool to clear the code.
6
After we cleared the code, the engine light stop flashing and no trouble code is shown. The result is no fault code.
7
The faults could affect the engine performance, by causing rough idle. Faulty MAP sensor may affect the engine performance, the engine will have rough idle, surging, rich mixture, spark plug fouling and loss of power due to retorted timing.
8
We can use the scan tool to check the fault code and match these flash code with scan code. Another way, we can test these sensor by using an oscilloscope to read their pattern and analyse. The pattern fro the oscilloscope show the real time numeric voltage data from these sensor, so we can compare these numeric data with specification data
Second We turned off the key and connect the wire from TE1 to E1 then we turned on the ignition key and the engine light is flashing. Record how many flash you see. For example: it flash once then pause then flash another six times, it means 16. After previous step, looking for diagnostic fault codes sheet then you can see which system is faults.
First thing, we have a visual inspection on the engine and then we look on MAP. ECT, TPS. IAT sensor to fine any physical damage, corrosion, broken wire, leak hose, and bad connection. Another way, wires shorted to other wires or earth. or mechanical problems that will cause an electrical code. After that, we found they are not plug properly. If they are connected properly, we can use an oscilloscope to read the pattern signal from these sensor.
Repair fault:
To repair, we plugged these sensor connector back and start the engine to make sure the engine run properly.
5
Usually, after we fixed or replaced these faulty sensor. The engine light will stop flashing. However, there is another way to clear code by pulling the EFI fuse to clear code from memory or we can use the scan tool to clear the code.
6
After we cleared the code, the engine light stop flashing and no trouble code is shown. The result is no fault code.
7
The faults could affect the engine performance, by causing rough idle. Faulty MAP sensor may affect the engine performance, the engine will have rough idle, surging, rich mixture, spark plug fouling and loss of power due to retorted timing.
8
We can use the scan tool to check the fault code and match these flash code with scan code. Another way, we can test these sensor by using an oscilloscope to read their pattern and analyse. The pattern fro the oscilloscope show the real time numeric voltage data from these sensor, so we can compare these numeric data with specification data
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