oscilloscope patterns

To get a oscilliscope patern I toock an osciloscopeand on the side of the engine was all the sensor terminal to make it easier to measure.I took the red terminal of the oscilloscope and put it into sensor I want to get the patern for and the black terminal in the bat- terminal and start the engine.then I change the voltage and time to get a better patern I did this throughout all my oscilloscope patterns.

The first oscilloscope pattern i did was with ECT.the voltage was 4.5-5v

With this one i put the time on 5seconds and the voltage on 2v for a good pattern.At cold temp the thermistor has a higher resistance.This would cause a high input signal at the ecu as the engine warms up the resistance gets lower and the voltage can change from around 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.

second pattern was map sensors pattern.The voltage range was from 0.5-3.5v

Doing this pattern i had the time on one second and the voltage on 2v for a acurate pattern.The bottom of the pattern shows idling.The top of first wave shows quick acceleration.The top of second wave shows cruising when accelerating the voltage goes up to about 3.5v under snap acceleration.when just on idle the voltage is about 0.5v this increases when more throttle is applied.There are some electrical faults that could cause this sensor to work incorrectly like,if the map plug is not in properly,when plug gets dirty,if there is not a 5v input or could also be a bad earth.This could cause a malfunction because if not getting a 5v input because of high resistance the ECU will think the engine is still on idle  and wont open the injectors enough so it will be running lean and have a lack of power.If there was a pattern of this it would show that the wave wont be very good. this could make the car have a lack of power.

The next pattern I did was with a tps with a voltage range of 0.5-4.5v

On this one I again had to have the time on 1second and the voltage on 2v.The top of the wave is wide open throttle and bottom line show idle.This pattern sows us when increaseing throttle the voltage increases.at the bottom where it a straight line the voltage would be about 0.5v and the top where it wide open throttle would be about 4.5v and line going up would be between that but increasing as throttle gets applied.This sensor could have electrical faults like bad earth,lose connection or plug might not be in properly.If these things occur the tps wont work or wont operate properly and the ecu wont get the right signal.If this would happen the patern waveform would have gap in it.this could cause the car to have a flatspot when driveing not just on acceleration but also on deaccelaration and if the fault realy bad could even cause car to not drive at all.

The next pattern was of a IAT sensor.

Doing this one I had to put the time one one second and the voltage on 2v to get a good acurate patern.At the highest point in this patern it is cold and at the lower point it is hot.In this pattern the higher the voltage the more air it is getting through the system.A bad coonection or dirty plug will cause this unit to operate incorectly.if this sensor would be faulty we will get a unconsistant patern.This will cause the car to run badly and jerk as the throttle is applied.

The next patern I did was rpm cam.

In this one I set the voltage to 2v again but the ime was alot different at 50ms the reason for this is because it is a patern that is usaly alot faster.In this pattern the waves all look similar but when adding more throttle the middle part of the wave gets bigger.This is the burn time.When just on idlle all the wave should look quite similar.A lose connection faulty magnet will cause this sensor to operate incorrectly.If it has a fault magnet the sensore wont me able to ground properly and will cause it to send the wrong voltage.This would make the pattern unstable and unconsistant This will make the car have a posible flat spot and could also have a lack of power.

My next pattern was of rpm crank

On this pattern I made voltage 5v and the time 2ms for a acurate pattern.This is a nice consistant pattern all of the waves about same when rev the car all waves change together.The top of the waves is the peak point on acceleration.bad earth could cause this unit to operate badly and give a bad pattern that is unconsistant.This will cause a bad drive with possible flatspots.

The next pattern was of a oxygen sensor.

For this one I had the voltage at 0.5v and the time on 2seconds.As this sensor heats up the voltage gets highe therefore the pattern gets higher all the way through.the funny looking bit at the start is quick accelaration.

The next pattern was of the injectors.

I had this one on 10v and 2ms for a good pattern.The bottom line shows the burn time then the line going up to top is charge time right at the top is the peak point and then coming down again it gets discharged.