WS3A Oscilloscope Patterns
O2 Sensor
Volt/division/range 0.83v
Time/division/range 2.5ms
A - As the voltage increase up to 0.8 this indicate O2 sensor's rich condition
B - As the voltage decrease below 0.2 this indicate Lean condition
C - Average voltage normally is up to 0.45volts
MAP Sensor
Volt/division/range 2.00v
Time/division/range 0.5ms
A - Faults reading shows the engines overload
B - Normal MAP signal
A - The engine idling,voltage decrease and High pressure on engine load.
B - Engine rev's up voltage increase and less pressure on vacuum.
C - Sudden decelerates cause the voltage reduce and pressure increase.
MAF Sensor
Time/division/range 200ms
A - MAF at it's normal signal at engine acceleration
B - Fault signal show MAF is not reach it's operation voltage as the engine rev's.
A - MAF at engine idle
B - Accelerating engine increase the signal voltage
C - Hot wire type sensor slowly reduce the voltage at de-accelerate.
AIT Sensor
Volt/division/range 2.00voltsTime/division/range 25se
A - Normal operation shows when the engine gets warm up the voltage decrease.
B - This is an example to show fault reading as the engines reach it's operating temperature but the sensor signal remain cold and the engine still running rich.
A - (High resistance)This indicate cold start as the engine's not reach it's operating temperature.
B - (Low resistance)This shows IAT is working as the engine operate temperature is reach.
TPS Sensor
Volt/division/range 2.00voltsTime/division/range 15ms
A - Acceleration engine shows the voltage increase as the TPS throttle is wide open.
B - This is an indication of the engine under-load shows TPS part throttle at wide open throttle. WS3B Oscilloscope Patterns
INJECTOR & O2 SENSOR
INJECTOR
A - Injector Open (ON)
B - Injector Closed (OFF)
C - Injector Voltage increase
O2 SENSOR
A - O2 Sensor rich condition
B - O2 Lean condition
D - The red arrow indicate a perfect shot showing the picture of the Injector (On time) as the Oxygen Sensor increases it's voltage to rich condition. The relation between the two components is when ever the Injector open to release fuel in the cylinder the O2 sensor induce the voltage toward rich condition.
This is another test exercise showing the ignition and Oxygen Sensor comes in one closed operation between two pattern.
A - The injector is now earth trigger, and switch on drawn the mixture into the cylinder.
B - As the injector start to pulse the ECU increases the voltage forcing the injector to closed. Showing the pattern at this point the voltage jump up to 11 to 13volts and even more.
C - This show O2 Sensors lean condition.
D - This point of the two pattern indicate their relation, (A) shows the injectors open time, once the fuel is compress and ignite, the exhaust valve open and the piston comes up pushes the gas to exhaust output. Now the O2 sensor is given that demonstration as it lean then rich up increase the voltage to about 0.8v at 2500RPM engine condition and with the frequency of 151.9Hz. The oscilloscope capture this moment.
INJECTOR Vs MAP SENSOR
A - Ignition spike at engine cycle. ( four cycle is one cranks revolution per injector).
B - Injector switch On ( Injector Open)
C- The Injector closed (Off) and high voltage is used to shot the injector.
TPS Vs INJECTOR
TPS at sudden acceleration show on graph above the voltage suddenly change as the throttle goes wide open, causes the injector to add more fuel in the cylinder, more air drawn results of the injector to open longer. In this excises we can now see the the injectors reaction time and voltage to the TPS position.
RPM Vs INJECTOR
Every four cycle of the engine gets a result of one engines revolution. As the frequency increase, the injector also pick up speed. The oscilloscope pattern above shows that with RPM increase the injectors’ frequency goes up. Injectors are opened faster and their duty cycle rises. Dynamics of these processes can be analysed in order to determine what is the fault if it takes place.
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