Primary and secondary ignition patterns

I had to use a lab scope to get the primary ignition patern with the engine on idleing.I did these following tests on the 4A-FE engine.My task was to record the average firing voltage,the avarege burn voltage,average burn time and the average dwell time.I had to do this for each cylinder.

                              cyl1         cyl2          cyl3        cyl 4
firing voltage          248v        248v        248v       248v
burn voltage          55.6v       55.6v       55.6v      55.6v
burn time              1.48ms     1.48ms     1.48ms   1.48ms
dwell time             6.2ms       6.2ms       6.2ms     6.4ms

all these voltage reading are normal because they are all the same or when not the same they are very close together.This shows a good steady primary ignition voltage.

In this oscilloscope patern it shows the charge and discharged pattern of the coil.As seen in this pattern it drops shows the dwell the it rises by alot,this shows the burn time.The burn and dwell time is both measured in ms.the voltage division of this pattern was 5v and time was 1s.

Using stacked display is an advantage because it makes the pattern more accurate can see the voltage the voltage drop and rise more acuratly.
Next task was to view secondary ignition patern.I was asked to record the firing voltage and the burn time for each cylinder.The first one I had to do was under snap accelaration.

                                cyl1            cyl2                cyl3            cyl4
firing voltage            5.4kv          6.2kv              5.9kv         6.2kv
burn time                 1.1ms          1.8ms             0.65ms       0.71ms
snap acceleration     9.8kv           8.4kv             9.8kv          9.0kv

In this result it shows that the secondary is not as consistant as the primary but not bad either.Also shown is that it does not hav the dwell time.

The picture above is the pattern of the snap acceleration secondary ignition.The middle part were it goes up is the part were we reved the engine.This is were the firing voltage is calculated.This picture is of cylinder1.This is similar to the primary but the fact that secondary does not read dwell time makes them different

Next on was with a spark tester.Do this by ataching a spark tester to sparkplug wire

                           Cyl1           cyl2           cyl3        cyl4
 firing voltage       13.9kv        6.4kv        6.4kv      6kv
 burn time            0.7ms          1.41ms     1.12ms    1.4ms

In this results it shows that the voltage goes verry high on cyl 1 but the drops and stays steady and at this time the burn time is lower.This is because the spark tester was on cyl 1

voltage division in this one was 4kv and time was 8.7ms.In this picture it shows that it has one spike.this is where it sparked and where the voltage was higer and the time was lower.

exhaust gas analysis

This was done on a 1992 nissan primera.To do these test I had to use a exhaust analyser.Before I could use it I had to warm it up and calibrate it.When this process was done I put the analyser probed in the tailpipe.First I ha to know what everything means:CO2=carbon dioxide.These readings indicate that the catilatic converter is working.CO=carbon monoxide.These readings indicat catalatic converter is not working and if car is rich, HC=hydro-carbon.this shows about the misfire in the engine.O2=oxygen.this shows if car is rirch or lean.

The first test I had to do was start the car and let it idle cold and record the readings.It usaly takes about 30seconds for a acuarute reading to show.I got readings of:
CO:49%  HC:340ppm  CO2:12%  O2:0.6%
The engine getting warmer but the catalytic converter stil cold that is the reason for the CO reading being higher than normal.The HC is also high this indicates a high number of missfire.this is also because car i still cold.

The next reading i had to take was when the car is warmed up.
CO:6% HC:171ppm CO2:12.8% :O2:0.08%
This result indicates that the catalytic converter is not working efficiently.The hc number has come down alot because the car is at a good tempreature and steady went into closed loop so idles better.

Next reading was at 2500 rpm
C0:39%  HC:245ppm  CO2:12.8%  O2:0.16%
The HC number has gone up again because we increased the revs so the misfire count went up because it is at higher rpm more strain on engine.CO is still high shows the catalytivc converter is not working properly.

Next task was to make the car run rich and record reading.I did this by spraying a little carberator cleaner into the intake.
C0:7.7%  HC:1800ppm  CO2:14% O2:-O.O2%
The CO has still not realy improved.The hc in this one is verry high which sows a verry high amount of misfire.The O2 is verry low.this show that the car is running rich.

Next I had to make the car run lean.I did this by removing a vacuum hose.
CO:0.3%  HC:1400ppm  CO2:7.8%  O2:9.8%
In this one the CO is good.The HC is still very high because it is running lean the missfire number is high.The O2 is realy high.This shows that the car is running lean.

I had to accelerate for a short time and record readings when CO is reading highest.
CO:4.2%  HC:240ppm  CO2:13%  O2:0.15%
The CO at its highest reading is not verry high.This shows that the cat is working.the missfire number pretty high because rpm increased.The O2 reading is good car not running to lean or rich.

Next I had to disconnect a spark plug and ground it.
CO:15.2  HC:1900  CO2:13.7  O2:0.9
In this task the missfire number was verry high because it is only running on 3 cylinders.The CO is getting higher this indicates the catalytic converter is trying to work.

I had to disconect one injector.
CO:1.8  HC:282  CO2: 10.3  O2:5.3
Cat converter working pretty good in this test.O2 reading hig indicates that the engine is running lean because with the one injector disconected engine is not getting enough fuel

Made other changes do see diference.The changes i made was I turned the aircon on.
CO:3  HC:240  CO2:13.1  O2 0.14
Only thing that quite hig in this test was the HC but not to high.

If I did all these test on a vehicle without a catalytic converter the readings for CO and O2 will be higer because it will run lean.lambda O2 sensors has 4-5 wire because extra wires are used for signal wires.

This is a picture of what it looks like to get the reading on the analyser.

oxygen sensor on car

I did the following tests on the 1zz engine.On this engine this sensor was located on the exhaust manifold just when it goes into one pipe.This sensor has 4 wires:
colour                                 use
white                                  signal
white                                  O2 sensor
white                                  ground
black                                 power heater

The sensor I was working with was a zirconia switching sensor.I had to hoock up a oscilloscope to the sensor to get a patern.I did this by back-probeing the signal wire and putting my oscilloscope to it.My first task was to get a pattern at 2500rpm.With this pattern I found that the higher the voltage gets the richer it is.

The voltage goes as high as 0.715v and it goes as low as 0.1v.The average voltage was 0.6v,the oscilloscope had a function to calculate this.This sensor had 3 cross count.One cross count is when it goes from low to high or high to low.

My next task was to get a pattern of the oxygen signal at idle in closed loop.Closed loop is when car is warm and the ECU uses actual information to adjust sensor and not a set map like open loop.

In this one the voltage only went up to 0.2v and went to as low as 0.1v again.0.15 was my average voltage and again it had 3 cross counts.

In the next task I had to make my oxygen sensor go rich and get the pattern.I did this by giving it a quick accelaration.

This gave out a higher voltage of over 0.85v.If this did not give a high voltage the voltage will be changed and will not give a good wave form.

Next thing I had to do was make the oxygen sensor go lean.I did this by running the rpm to 3000 then sudenly dropping the throttle.

The voltage dropped from 0.8v to 0.1v.This shows us the lower the voltage the leaner the car is running.If the voltage is not high the waveform will be bad and wont go down as low as it should.

Next thing I did was measuring the response time I did this by sudenly acceleratin to see how quickly the sensor went from lean to rich.

The voltage went from 0.1v all the way up to 0.8v the bottom is at idleing the goin up is at accelerating and the top is when it is rich.It took the sensor 100ms to go from rich to lean


The zircronia sensor is based on a solid-state elctrochemical fuel cell called the nernst cell.On this system when the voltage is 0.2v this indicates a lean mixture and at 0.8v it indicates a rich mixture.It is most sensitive near stiochmetric point and less sensitive when rich or lean.

this is a good picure of http://www.wikipedia.org/ to show how the sensor works.

scan tool diagnostics

We did this on the 1zz engines.We were given a scan tool.

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first I had to know what the folowing means

Type of information(PID=Parameter Identification)	Letters to describe it	Value of data	Units for data
Engine Load(how much air comes in)	AFM(MAF)	2.58	Gm/s
Engine RPM	Engine speed	700	RPM
Throttle angle	Throttle position	11	%
Engine coolant temperature	Coolant temperature	71	C
Intake air temperature	Intake air temperature	22	C
Fuel Injection opening pulse	Injector pulse width	2.7	ms
Transmission select position	shift	4
Vehicle speed	0	0	Km/h
Oxygen sensor(s)	O2 sensor B1 S1	0.89	V
Fuel Trim	Short fuel trim#1	-20.3	%
Idle control	IAC duty ratio	37.5	%
Power steering condition	PS	off
Air Conditioning condition	A/C cut signal	on
Exhaust Gas Recirculation(EGR)	-	-	-
Fuel Evap or Purge condition	EVAP VCV	OFF	-
Malfunction Indicator Light	Warning light/MIL	on	on
I got this information from http://ttec4826-vlad.blogspot.com/2011/05/scan-tool-diagnosatics.html

I plug the scantool in to the diagnostic plug the I got the lecturer to create a fault.He did this and after selecting the vehicle and engine on the scantool the fault code came up.The code number was po120 I looked it up and found that it was the tps.The lecturer switched this of.By doing this he had caused a circuit malfunction.After this I had to find out what parameter identification of system voltage(pid)has changed. the type of informayion is throttle position letters to describe this is tps value of data is 0 units for data is % I did this with ignition on.I did a visual inspection to find the fault.To do this I checked for corotion,I checked plugs to make sure they are in properly.I checked all the wires and chech yhe voltage.I found that there was a circuit malfunction and when i could not repair it I got lecturer to turn back on.On the tps the yellow wire is the 5v supply the brown is the reference and the green is the signal wire.To clear the codes I said clear codes on scantoolI turned the ignition of. to recheck the codes I turned ignition on again and no codes came up.Live data is important because it shows faults and changes in the system and what is happening with the faults in the system.parameters is needed when checking live data because it shows changes and what is hapening in the system.A scan tool can aid you when fault finding because it is acurate and tels you what is wrong to be able to fix the car faster.

Dual trace oscilloscope

Doing the dual pattern works the same as doing the normal one but you just get two paterns.I still used the same oscilloscope but but went to menu and turned patern b on this makes it posible to see two patterns.hooking it up was not hard.I used one earth that went in the bat- terminal on the 1zz engine and then I had two red wires in two diferent terminals of the osciliscope then I put them in the terminals of the sensors patern that i wanted.When i got goo paterns I pased them and got the result.This can also be done with two oscilloscopes if needed.

The first pattern I got was map against injectors.The voltage for the map was 1v and voltage for injectors was 20v.For this one I used two oscilliscopes.The reason for this was because the map is alot slower than the injectors so I couldnt realy get a good reading for them together.So I used two earhts and started them same time and paused them at the same time aswell to get a good afective pattern

The left side is the injector and on the right hand side is the map.on injectors bottom line is burntime and goin up is charging and on the map as it goes up its getting more air.The two components relate to eachother because.When the map sensor goes up it means it is getting more air.This means the injector will spray more fuel because the ECU can see there is more air so there has to be more fuel.There is also more frequency at the injector when there is more air.the higher the map signal is the bigger the burntime of the injector would be because when it goes higher it gets more air so it needs more fuel.The components affect eachoter because if the map is faulty the air reading might be wrong so it wont spray right amount of fuel and it would make the car run badly.

The next pattern I did was for rpm crank vs injector.For this one I used one iscilloscope because it was all i needed.The voltage for the rpm crank was 10v and the voltage for the injector was 50v.When I first did this it did not work then I realized the crank sensor was not connected so I moved to another engine.

The bottom pattern is the rpm and the top patern is the injector.I had the time on 2ms.in the injectors were it goes doen between that and before it goes up again is burntime.with the rpm top is peak point.If I ad throttle the gaps between waves of rpm wil opn more.These components relate to eachother because as soon as the crank meets the o point the injector switches on.The slower the time which was 2ms in this time the bigger the burntime of the injector.This means that the components can affect eachother in a big way because if the crank sensor is faulty the injectors wont turn on when it should and cause the car to run badly.

The next pattern was for oxygen sensor against injectors.I did this one on a 4a-fe engine.

I had the oxygen sensor voltage on two volts and the injector voltage on 10v and the time on 5ms.the injector stil same. the oxygen sensor does not do much because the o2 sensor not as fast as injecor.These components relate to eachother because the oxygen sensor measures the gases and sends to ecu and makes injectors spray more or less.If there is a faulty O2 sensor the injectors might spray too much or too little fuel.this would cause the car to run lean or rich and could cause it to use more fuel.

The next pattern I did was for ignition primari against injectors.

I had the voltage of the injectors on 20v and the ignition on 5v with the time on 5ms.In this pattern the two wave forms are directly above eachother like the burntime of the injector is even with the ignitions time.when we rev the car the ignition goes up aswell as the injector pattern.these relate to each other because when ignition goes up injector sprays.This means if the ignition faulty the burntime of the injector will be wrong and the car will run badly might also run rich and use more fuel.

The last patern I did was ignition primary voltage against ignition primary current

The current rises as the primary circuit is completed as it show in this pattern the top one is the current and the bottom is the voltage of the primary ignition.I used a ohmmeter that i hoocked up with the oscilloscope to get the current pattern.

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.

input sensors and actuators on car

The tests I did for this were done on a 4a-Fe engine commonly used in a 1992 Toyota corolla.The first test I did was to measure the voltage to the fuel injector,I did this by back probing the wire to the fuel injector with a pin.I got a result of 14v which is a good result.It is important to check the voltage of the fuel injectors because if the voltage is to low the injectors wont operate properly which will cause the car to run badly.If the voltage at the injectors are lower than the battery voltage the injectors wont open properly and wont be fast enough.This could be cause by bad connection going to the supply.I was asked to draw a circuit of the fuel injector.

The picture above is a picture of the circuit I drew with all the components named.

The next sensor I did was tps (throttle position sensor).The tps has a 5v reference in this case it was the yellow wire.The reason for a 5v reference is because it is the power to the sensor this is to provide a good signal to the tps.Sometimes the reference voltage could be wrong.This could be caused by a high resistance in the feed because it is a straight feed.The next test I did was testing the ground at tps sensor.I used a pin to back-probe the sensors earth.I used a multimeter I put the red terminal on the pin and the black terminal on the engine to ground it I put my multimeter on dc volts and got a result of 0.002v.This result shows me that there is a good earth.This is important because if there is a bad earth the car wont run properly.A broken earth wire can cause the ECU to have a bad earth.I located a tps input and back-probed the wire measured voltage with a multimeter with the ignition on and got a result of 0.384v.I opened the throttle half way and got a reading of 2.23v then i opened the throttle all the way and got a reading of 3.789v.I did a test by slowly opening the throttle fully from closed and watched the reading increase slowly this means it is good result.A tps sensor works by using a input voltage and a variable resistor around a shaft to send a output voltage from .5-4.5v depending on relationship between shaft and variable resistor.The ECU should usually get a voltage of 0.5v at idle from the sensor to 4.5v at wide open throttle.There are some things that can prevent the tps from sending the correct voltage like faulty earth,faulty input and also faulty tps.I was asked to draw a circuit diagram

The picture above is the circuit I had to draw.The reason there is a output needed for the ECU to properly run the engine is because the ECU needs to adjust all the sensor to what the driver is doing for example:when the driver is driving a wide open throttle the car needs more fuel therefore the injectors needs to spray more fuel.

The next sensor I tested was the engine coolant temperature sensor.

I found the ect on this engine then I back-probed the supply wire to the ect.I turned the ignition on and used my multimeter to measure the voltage at this point and I got a result of 3.58v.The engine is at normal temprutare at this point.I started the engine and measured voltage again and I got a result of 1.1v.This result shows the sensor is good because the voltage decrease whhen the engine tempreture increases.The ect works with a set resistance in the ecu that make the use able to adjust sensor to the engine.The ect voltage can also affect the fuel injection because a higher output from the ect at cold tempreature gives a higher voltage to the ecu causing it to ground injectors for longer.A faulty thermister or a faulty earth will give the ecu the wrong voltage which could cause the car to run badly.I back-probed the black wire which is earth and measured voltage with multimeter and got a result of 0.1mv this result shows sensor has a good earth.A lose connection could cause a bad earth.

The picture above is a picture of a circuit diagram I got this of google images.

The next sensor I did was the rpm sensor.
To test this sensor I back-probed a rpm signal wire with a pin and put my multimeter on ac volts.I strarted the engine and measured the voltage and got a reading of 90mv.I increased the rpm to about 2500 and got a reading of 197mv.I switch the multimeter to dc volts and at idle I got a reading of 1.2v.I then again increased the rpm to 2500 and got a reading of 16mv.I then switched the meter to Hz and got a reading of 5kHz after increasing rpm again I got a reading of 7.5kHz.These result shows that Ac voltage was the best way to see if the rpm sensor is working.The 4a-fe engine I was using had a hall effect type rpm sensor.This type of sensor works with a magnet and a plate plate pases through the magnet then it grounds and sends a voltage out the sensor wire.It is good to use diferent functions of the meter to get acurate results it gives us an idea of what the patern would look like because we know the size and power amount of it.


The next sensor i did was map or maf sensor.
I backbrobed the map sensor and measured the voltage with the ignition on and got a result of 1.8v.I started the engine and let it idle measured it and got a reading of 0.48v.Then i gave it a quick short accelaration and got a result of 1.8v.The map sensor works with presure and measures it and sends it to ECU with the signal wire and the ECU adjust the engine to that result by using other sensors.the readings i got was correct because it went up when short acceleration because there is more preasure.bad conection or pipe not on could give ecu bad reading

This is a circuit diagram of a map sensor.

The next sensor I tested was the IAT(intake air temp)
I had to back-probe the sensor and turn the ignition on and measured voltage and got a result of 3.3v.This reading is 0.2v less than that of the ect.This show that the iat is hotter than the ect.The IAT works by measuring the temp goin through the intake and sending it to the ecu.The IAT voltage effects the ecu for fuel injection in the same way as the ect if it is wrong the injotor time would be wrong.The sensor signal sends out a higher signal if the tem rises.A bad connection or bad earth can cause the incorect signal for the ECU

Next sensor was camshaft position sensor
I had to measure the cmp in 4different settings to find the best one.
DCvolts:19.5mv
ACvolts 1.2v
hertz:0.09kz
%duty cycly:14.1%
duty cycle best way to measure this.