WS8 Primary & Secondary Ignition Patterns

TOYOTA  4A-FE

Warning: Ignition coils create high voltage. It can be dangerous, so avoid getting too close to ignition parts when engine is running. Make your connections when the engine is off, and then keep your distance when the engine is running. Even some primary voltage is high enough to stop a “Pacemaker”.  

Also: Do not run engines with secondary ignition HT leads “open circuit”. Make sure they are grounded to engine through a spark plug, grounding wire, or spark tester.

If you have problems with the task, see you lecturer for help.

1.0 Primary Voltage Patterns 

1.1 Set up a lab scope or ignition oscilloscope to view the primary ignition pattern (in parade or display mode) on your lab scope, with the engine warmed up and idling.  

1.2 Record the average Firing Voltage (or “Step Up voltage) for each cylinder in the chart below. Some variation is normal, just pick the average. If you don’t understand what this is, review the resource information available. 

1.3 Record the average Burn Voltage for each cylinder in the chart below.  

1.4 Record the average Burn Time in milliseconds for each cylinder in the chart below.

1.5 Record the average Dwell Time for each of the cylinders in the chart below. What unit of measurement are you using to measure the dwell time?

5.5ms

1.6 Are all these primary ignition voltage readings normal? Yes _√__ No ____ Please discuss what is normal or abnormal about this pattern and what causes it?

 
From the primary ignition pattern, firing voltages were at + 300 v in all cylinders and burn voltages were around 50 v in all cylinders. Next, burn time and dwell time were at 1.5ms and 7ms each in all cylinder. As a result, primary ignition pattern is normal with correct values and four cylinders have similar ignition pattern.


                                  Cyl1     Cyl2    Cyl3    Cyl4
Firing Voltage          +300v  +300v  +300v  +300v 
Burn Voltage              50v      50v       50v      50v
Burn Time                  1.5ms  1.5ms   1.5ms  1.5ms
Dwell Time                 7ms     7ms      7ms     7ms


1.7 Draw or photograph the Primary Ignition oscilloscope parade pattern from your scope into the box below. Do it carefully and show the detail you need to see for diagnosis. Record voltage and time scales.

 

1.8 Discuss what the primary display or parade pattern emphasizes for diagnosis. What can it help you see?

From the above waveform,I can check the 6 stage of ignition pattern in 4 cyclinders.

1 battery supply voltage

2 dwell time

3 firing kv

4 spark burn time

5 continuing

6 isolation

2 is the Dwell part of the pattern. This is where the coil is actually turned on by the vehicle's control module. The coil is building up a strong magnetic field to spark the spark plug during this part of the pattern.

3 is the part of the pattern where the spark is actually firing. The initial spark uses the most voltage, as the spark is generated less voltage is needed to maintain the spark and the voltage drops. The amount of time the spark stays active and the amount of voltage needed to keep the spark going can give you clues as to what's going on inside the cylinder. A low starting spark line could indicate that that the spark plug could be oil fouled, that a short in the spark plug wire is present, or that the cylinder compression is low.

5 to 6 is the part where the coil is turned off and the magnecit field that the coil has generated is now collapsing. You can get an idea what shape your coil is in by watching the osolations just after the spark plug is done firing. If there are fewer than four osolations at this part of the pattern then there could be some shorting in the coil.

1.10 Some scopes have the facility to use raster or stacked display. How could this help you to diagnose a fault. What can you see more clearly?

I can control the size of voltage and time and the waveform can be bigger, so I can see more clearly with detail information.

2.0 Secondary Voltage Patterns

2.1 Set up your ignition oscilloscope or lab scope to view the secondary ignition patterns on your lab scope, with the engine warmed up and idling. (Use parade mode or individual mode on each different cylinder, depending on scope available.)

2.2 Record the average Firing Voltage (or “Step Up voltage) for each cylinder in the chart below. Some variation is normal, just pick the average. If you don’t understand what this is, review the resource information at the back of this worksheet.

2.3 Record the average Burn Time for each cylinder in the chart below.

Are all these secondary ignition voltage readings normal? Yes _√__ No ____ Discuss what is happening in the pattern and what it is telling you about the ignition system.

From the secondary ignition pattern, firing voltages were at 5 kv in all cylinders and burn times were at 1.4ms in four cylinders. As a result, secondary ignition pattern show normal conditions with correct values.

2.5 Do a Snap Acceleration (don’t damage the engine by revving too high or for too long) and record in the chart below how high the Firing Voltage (KV) went under Snap Acceleration. 

                                   Cyl1   Cyl2   Cyl3   Cyl4
Firing Voltage            5kv    5kv     5kv    5kv 
Burn Time                 1.4ms 1.4ms 1.4ms 1.4ms
Snap Acceleration     8kv     8kv     8kv    8kv 

2.6 Are all these Snap Acceleration secondary ignition voltage readings normal? Yes _√__ No ____ Discuss what is happening and what the pattern is telling you.

When the snap acceleration is added, the firing voltage slightly increased. This means that higher rpm needs higher firing voltage with short burn time.

 

2.7 Draw or photograph the Secondary Ignition lab scope pattern while idling from your scope into the box below. Do it carefully and show the detail you need to see for diagnosis.

2.8 If you can safely do this, (with the engine stopped), gently disconnect one spark plug wire, and short to the engine with a jumper wire. Which cylinder number did you short? __4__

2.9 Start the engine and let it idle (for only a short time.) Record the new Firing Voltage and Burn Time for all the cylinders in the chart below.

                                Cyl1       Cyl2       Cyl3       Cyl4
Firing Voltage        6kv         6kv         6kv        4kv
Burn Time              1.4ms     1.4ms     1.4ms    1.8ms

2.10 Draw or photograph the shorted Secondary Ignition waveform you see now on your scope.

2.11 Discuss what is happening in the shorted ignition pattern and how the ignition pattern tells you what it is happening in the ignition system.

When the spark pulug is shorted, the firing voltage drops to 4kv and the burn time increases to 1.8ms because there was not a spark gap.

2.12 Remove the ground wire and attach the spark plug wire back on the engine so it is normal again. Run the engine a bit to clear the spark plug.

2.13 Stop the engine and attach a spark tester to another spark plug wire. Start the engine and let it idle (for only a short time). Record the new Firing Voltage and Burn Time for all the cylinders in the chart below.
                               Cyl1     Cyl2    Cyl3      Cyl4
Firing Voltage       5kv       5kv      5kv        9kv
Burn Time             1.5ms   1.5ms  1.5ms   1.3ms

2.14 Draw or photograph the spark tester Secondary Ignition waveform you see now on your scope. Show the detail that is necessary for accurate diagnosis. Include time and voltages.

2.15 Stop the engine, remove the spark tester (be gentle), replace the spark plug wire, and run the engine to clear the spark plug. The engine should be back to normal now. If not, tell your lecturer. 

2.16 Discuss what happens to the ignition waveform when the spark tester is attached to the spark plug wire. What does it tell you about the ignition system.

When the spark tester is located at bigger spark gap in #4 cyl, the firing voltage increases to 9kv and the burn time decreases to 1.3ms because there was a bigger spark gap.

As a result, the firing voltage and burn time are related to the spark gap. If spark gap is small the firing voltage will decrease and the burn time will increase. On the other hand, if spark gap is big the firing voltage will go up and the burn time will drop.

2.17 Remove the spark tester carefully, and put everything back together on the engine. Engine runs fine? __√__ yes, or ____ no. If any problems with vehicle, please tell your instructor.

reference by http://www.linnbenton.edu/

WS4 Fuel Pressure and flow

WS4 Fuel Pressure and flow (Petrol only)

TOYOTA  4A-FE 

 Warning, be careful around raw fuel. It can catch fire! Use appropriate safety precautions. Keep sparks, flame, your body and your clothing away from raw fuel! Know where your fire extinguishers are and use them if necessary.


1. Locate the two closest fire extinguishers. (If you have to use it remember to pull the pin, squeeze the handle, and spray at the base of the flame.) Write down where they are:
Fire extinguishers are located beside the main gate.

2. If you can, look up Fuel Pressure specifications for the vehicle you are testing. If you can’t look them up, make a guess at the fuel specs you should have and write them down here:
265 ~ 304 kPa (2.7 ~ 3.1 kgf/㎠, 38 ~ 44 psi) 

3. Use eye protection. Optional: Relieve fuel pressure before installing pressure gauge. Or there will be some fuel that sprays at you as you attach the gauge. You can relieve pressure by several methods: 1) To relieve the fuel pressure. Make sure you have a rag to catch the fuel, start the engine. 2) Remove fuel pump (circuit opening) relay or fuse and run the engine until it stops, then crank to check that the engine doesn’t start 3) Use a vacuum gauge on the pressure regulator to lower fuel pressure, or 4) Open a fuel line at some pressure point and catch the fuel in a rag beware there may be lots of fuel.

4. Attach fuel pressure gauge and notice which scale on the gauge you will be using. Briefly turn key on or start vehicle, then turn it off. Check for fuel leaks.
Are there leaks? Yes ..................... No .....√.......
If there are leaks you must correct them and retest before continuing. If you need help, ask !

5. Measure the fuel pressure with the key on, engine off.
Record it here: 270 kPa (also record the units you are using, psi, bar,
Kpa, etc…)

6. Idling: Measure the fuel pressure with the engine idling. Watch the pressure for a couple of minutes.
Record pressure here: 250 kPa

7. Maximum: With the engine idling, use the special tool to clamp the fuel return line. Note: this can only be done for a short period.
Record pressure here: Over 600 kPa

8. WOT: With the engine idling, disconnect and plug the vacuum line going to the fuel pressure regulator.
Record pressure here: 310 kPa 

9. Residual: Turn off the engine, and watch the fuel pressure for five minutes.
Record your residual or rest pressure here: 270 kPa

10. Flow: Hook up proper equipment to read fuel volume if necessary. Record flow gauge results of volume, or how much pumped in 15 seconds: (normal results may be ½ liter in 15 seconds)

Around 690 ml

11. Replace vacuum lines. Carefully remove the fuel pressure gauge (beware of fuel spraying into eyes, avoid sparks, etc.) Turn engine key on and off, check for leaks. Start engine, check for leaks. No leaks? Check here:
Replace cap over fuel pressure test port. Check when done: OK


Make sure the vehicle is safe and runs fine when done, or tell your instructor.

12. Explain why it is important to know a vehicle fuel pressure/flow?
 The injector operates correctly under the correct fuel pressure.

13. Describe the symptoms a vehicle would give with each case

Low fuel pressure
The engine idling drops and the engine runs roughly. The engine performance reduces significantly.

Low fuel flow
Low fuel flow is occurred ed by blocked fuel filter and weak return valve and fuel pump. This produces low fuel pressure and rough idling as well due to insufficient fuel supplying for injectors.

High fuel pressure
High fuel pressure is produced by the fault of the return fuel regulator. More fuel goes through the injectors with dripping fuel to the injectors. 

Faulty fuel pressure regulator
Flooding of injectors with high fuel pressure which will leak out the injectors. This causes hard starting, poor economic and the high consumption of the fuel. 

WS2 Flash Codes

TOYOTA  Cynos Juno  1995

Warning: Be careful working around engines and exercise caution to avoid injury.

Note: The engine check light must be working.

If you have problems with the task, see you lecturer for help.

1. Flash/Blink Codes

1.1 Find a engine/vehicle that you have the workshop manual with the correct procedure and codes to diagnose the flash codes

1.2 Have your tutor create a fault in the EFI system

1.3 Using the workshop manual follow the procedure to extract the codes, explain briefly what is the procedure

Firstly, When the ignition switch is turned on, the check engine light should light up then the engine is started, the light should turn off. Secondly, If the faults are found the diagnostic plug should open and connect between TE1 and E1. Thirdly, the ignition switch is turned on, the check engine light should flash according to fault codes. If the TPS has a fault, the light will flash four times and the light will turn off for a little while. And then, the light will turn on one time for second fault code. Next, I can check the fault codes from the manufacturer specification and I also find out other problems. The fault codes should be clear, after I repair the faults. Finally, the fault codes should be rechecked. When the E1 and TE1 of diagnosis box are connected, the check engine light should continuously flash under normal conditions.

2 Trouble Codes or Fault Codes

2.1 Find where the Codes are listed

2.2 Record any codes, and what system and condition they describe in the chart below (Example: might be code number 21, for Throttle Position Sensor, signal voltage too low) 

Code number   System affected   Condition described

41                        TPS                        No voltages(Idle normal)

 

33                        IAC                         Engine idle is high

31                       Vacuum Sensor      The engine is turned off and rough idle

 

3 Visual Inspection to find fault

3.1 Do a visual inspection under the bonnet to find where the problem is. Use information from the code to know where to look for the problem and what type of problem to look for.

3.2 Describe the problem(s) you found:

Following the fault codes, I found the disconnection of some sensors, such as  TPS, vacuum sensor and Idle air control sensor.

4. Repair fault

4.1 Plug back in the connector, or repair problem found

Describe what you did:

After plug back in the connector, I have checked the engine condition and retested the signal voltage of sensors. The engine have recovered with appropriate conditions.

 

5 Clear Codes

Describe what you did to clear the codes:

I made a disconnection of negative terminal of a battery or main fuse for 30 seconds.

6 Recheck for codes and record codes in system now:

After clear codes, E1 and TE1 of diagnosis box should be reconnected. When the ignition switch is turned on and the engine is not running, the check engine light is contantly flashing that means normal condition of the engine without any faults.

7 How could the faults found affect the engine performance?

From the faults, the engine does not run properly and has abnormal conditions with lower engine performance.

8 Discuss what other tests you should be doing once you have found the fault codes:

I can recheck the voltages of sensor's signal using a multimeter and lab scope with manufacturer specification. In addition, I can find out the fault codes easily from using scan tool diagnostics.

WS1 Petrol Fuel Injector Testing

WS1 Petrol Fuel Injector Testing

Make TOYOTA Model 4A-FE Year ...........

Warning, be careful of diesel common rail injectors. They can have very high voltage; do not touch the electrical connectors. This worksheet is only for petrol engines that have up to 15 volts at the injectors.

1.Listen to the injectors as the engine is idling. Use stethoscope, vacuum line or long screwdriver. Be careful of moving parts. They should sound like a sharp tap, not a dull thud or nothing.

This is a crude test to see if they are being actuated and are opening.

OK ....O.... Not OK ..........

Can you get to all the injectors? Yes ....O.... No .........

Comments: All injectors properly work and have good conditions.

2.Check voltage to the injectors when idling or Key On. This makes sure you have battery voltage to the injectors so they can work.

Record battery voltage: 14.16 v

Record voltage at each injector you can get to by back probing. Be careful to not puncture or damage wiring.

Cyl #1	Cyl #2	Cyl #3	Cyl #4	Cyl #5	Cyl #6
14.11 v	14.12 v	14.11 v	14.11 v				Volts

3.With engine idling, watch injector firing by using an LED tester or test lightECM to fire, the test light should also be grounded to fire, and will flash.

Cyl #1	Cyl #2	Cyl #3	Cyl #4	Cyl #5	Cyl #6
√	√	√	√			Tick if flashes OK

4.With engine idling, watch injector firing by using a multi-meter set to read % (duty cycle). Record the readings for each cylinder at idle in the boxes below.

Cyl #1	Cyl #2	Cyl #3	Cyl #4	Cyl #5	Cyl #6
1.1%	1.0%	0.9%	0.9%				Duty cycle %

5.With the multi-meter still set to read % (duty cycle), accelerate the engine with short, fast throttle openings (don’t over-rev or damage the engine please), and note in the boxes below the maximum % reading you can get on the multi-meter: note the RPM.

Cyl #1	Cyl #2	Cyl #3	Cyl #4	Cyl #5	Cyl #6
5.1%	9.6%	6.3%	7.9%			Duty cycle %

6.Set the multi-meter to read Hz, and with the engine idling, record the readings for each cylinder in the boxes below:

Cyl #1	Cyl #2	Cyl #3	Cyl #4	Cyl #5	Cyl #6
7Hz	7Hz	7Hz	7Hz			Hz

7.With the multi-meter still set to read Hz, increase the engine RPM (don’t damage the engine), and watch how the Hz changes. Record your highest reading in the boxes below: Take the readings at the same RPM as you used in question 5.

Cyl #1	Cyl #2	Cyl #3	Cyl #4	Cyl #5	Cyl #6
15Hz	15Hz	15Hz	15Hz			Hz

Using this formula calculate the pulse width of each injector both at idle and when the engine is revved up

“Pulse width ms= (% Duty cycle/100)/Frequency”

Show your calculations

#1 cyl idle : (1.1% / 100) / 0.007kHz = 1.57 ms
#1 cyl revved : (5.1% / 100) / 0.015kHz = 3.4 ms
#2 cyl idle : (1.0% / 100) / 0.007kHz = 1.43 ms
#2 cyl revved : (9.6% / 100) / 15Hz = 6.4 ms
#3 cyl idle : (0.9% / 100) / 0.007kHz = 1.29 ms
#3 cyl revved : (6.3% / 100) / 0.015kHz = 4.2 ms
#4 cyl idle : (0.9% / 100) / 0.007kHz = 1.29 ms
#4 cyl revved : (7.9% / 100) / 0.015kHz = 5.27 ms

Cyl #1	Cyl #2	Cyl #3	Cyl #4	Cyl #5	Cyl #6
1.57 ms	1.43 ms	1.29 ms	1.29 ms			Calculated Time at Idle
Cyl #1	Cyl #2	Cyl #3	Cyl #4	Cyl #5	Cyl #6
3.4 ms	6.4 ms	4.2 ms	5.27 ms			Calculated Time when revved

Give your conclusion on whether this is an acceptable way to test injectors and why?

From the petrol fuel injector testing, when the engine is idling, the duty cycle and frequency values are lower than high rpm condition. As a result, the injectors shortly open when the engine run with idling, however the injectors open longer with more fuel injection when the engine runs with higher rpm.