I did this on the 1zz engines.On the left side of the engine was all the terminals named to make it easier for us to get an oscilloscope reading without dameging the wires and sensor by back-probing all the time.Oscilloscope is a very efective way of checking sensors because it gives a good pattern and shows wats happening right now and can show changes when u play with throttle or fuel extra.
The first sensor on the list was ECT.
the voltage was 4.5-5v
I set the time on 5s and the voltage on 2v.The reason for changeing the time and voltage is to get a good and effective pattern.As seen in my other post we found that the ECT is a negative coefficient thermister.This means that the resistance is higher when the engine is cold.This would cause a high input signal at the ECU and as the car warms up the resistance will be lower therfor the voltage goes from 4.5-5v.There are some electrical faults that can make this sensor operate incorrectly like,if it has a bad earth,could have a faulty thermistor,dirty plug or a lose connection.The reason these things will make the sensor malfunction is.If we had a high resistance of 1kohm int the earth it would cause a high voltage output to the ecu.this will cause the car to run rich and use more fuel.If this would happen the pattern would have gone up faster than it is going up at the moment.
MAP SENSOR PATTERN
voltage range was 0.5-3.5v
To get an accurate pattern for this one I had the time on 1s and the voltage on 2v.
Where we can see the pattern at the bottom this is were I had it on idle,this was at 0.5v.The first wave is snap accelaration and this was at 3.5v.The second wave is cruising and as we can see it is a much wider wave than the other one the reason for this is that if u apply throttle wave goes up and wen take of goes down so at cruising u wil aply throttle slowely and get quite a wide wave.If there is a electrical fault like plug not in wires open or damaged dirty plug bad earth we will be able to see this in the pattern because the ecuwil get the wrong reading and this will cause the pattern to be inaccurate and unstable and not very consistant.These faults wwil also interfere with the car,could cause a lack of power use more fuel and have some flatspots.
THROTTLE POSITION SENSOR PATTERN
voltage range was 0.5-4.5v
My time and voltage was the same as the map where the time was on 1second and the voltage was on 2v.This was very good for me because made it nice and easy because i did not have to change nything on the oscilloscope.Again the bottom of the wave shows wide open throttle and as the wave climbs up it shows more throttle being added and at the top of the wave shows wide ope throttle.electrical faults is about the sanme but another fault is also when the tps is in the wrong posittion.If there is a fault with the TPS the car wil be realy bad to drive could have slow reaction when applyin throttle could also have bad idle.At the worst case the car wont be able to drive at all.
INTAKE AIR TEMPERATURE SENSOR PATTERN
Again i had the time and voltage same.this patern is just a simpel pattern not as technical as the others.The highest point of the patterns is showing that it is cold and the lowest point of the pattern is showing that it is hot.The higher the voltage the more air is getting through the system.A dirty plug or a bad earth can cause this to go wrong and give a wrong voltage and ECU wont acuratly know if it is hot or cold.
RPM CAM
This is a very important pattern to have.If this pattern is not up to standards then it could cause the car to run badly or not at all.It is also very important to get the time and voltage right to get an accurate pattern.The time has to be alot faster to get it accurate because it on cam it very fast.
I had my time on 50ms for the reason that I explained that it has to be fast.My voltage just on 2v again just for the reason that I got a pattern out of it.In this pattern we can see alot of waves are consistantly the same but the middel part goes wider when we add more throttle we call this burn time.At idle it should be almost the same.when we have a bad sensor or bad earth this could cause the patern to be unstable and stil wil mean the car wil run badly and have a flat spot.
RPM CRANK
I had to use 5v for voltage and 2ms for time.This pattern works a bit differently if you add throttle the whole waveform wil change together.Top of the waveform is when it is at peak point under acceleration.
All of these patterns are important to give a good drive for the car and the driver.This is a very good and efective way of checkin all the sensors and also a good wau for fault finding just because of the reason that a gives a good live data.
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