Make :: Toyota
Model:: 4A-FE
Ws8 Primary and Secondary Ignition Patterns.
- To check the primary voltage i connected the oscillescope to the negative side of the primary coil and the negative to the body of the engine.
- All the primary voltages are normal according to the specifications.
- Below are the specs.
Cyl1 | Cyl2 | Cyl3 | Cyl4 | Primary Ignition |
244.5v | 244.5 V | 244V | 244.2 V | Firing Voltage |
27.8 V | 22.2 V | 27.8 V | 25.9 V | Burn Voltage |
1.65 ms | 2.4 ms | 2.3 ms | 1.3 ms | Burn Time |
4.4 ms | 7 ms | 6.8 ms | 7 ms | Dwell Time |
- The average Dwell period is shown on the graph below and we are going to measure this using "Micro seconds, or milliseconds".
- Firing time shows the .5 sec of time in the graph which is expectable under the specs for this engine..
- Firing voltage is the long string from the bottom, rite to the top. this is the voltage used to keep burning the fuel, mixture.
- Burn time shows how many seconds the mixture burnt for ,
- By obtaining these readings we can tell the small details in the ignition system.
- For example if the burn time is longer then it is ,then this shows us that this is happening because for a faulty spark plug, ignition coil, or there could be a high pressure in the fuel line, having these readings makes it easy to Narrow down the problems that could occur.,.
Afet a QUik rev of the engine i recorded the Secondary Voltage pattern shown in he graph below
Cyl1 | Cyl2 | Cyl3 | Cyl4 | Secondary Ignition |
10 | 11 | 12 | 14. | Firing Voltage(KV) |
0.52 | 0.51 | 0.48 | 0.46 | Burn Time(ms) |
1168 | 1168 | 1168 | 1168 | Snap Acceleration |
- All these readings of snap accelerations in the secondary ignition voltage are accurate and smiler with oneanother,
- In this reading it is easier to read the dwell time because it shows the next firing pattern,,
- The next ignition pattern is copied by the same pattern as the previous , this
- carries on.
- This shows what is happening inside the combustion chamber when the engine is running, (ignition pattern, coil working,and spark leads.
FOr then next experiment I shorted the 2nd spark pug wire to the engine with a jumper wire.
The readings are recorded in the table below.
Cyl1 | Cyl2 | Cyl3 | Cyl4 | Secondary Ignaition |
8 | 24 | 9 | 9 | Firing Voltage(KV) |
1.00 | 0.02 | 0.28 | 0.40 | Burn Time (ms) |
- This reading clearly shows that in cylinder 1 .. it takes time for the spark to jump across therefore more burning time and firing voltage requierd.
- Reading of cylinder 2 is taken as a picture for closer observation.
- The burn voltage shoots higer as shown in the graph.
- The firing time takes a bit longer than usual as well.
For the next test I turned the engine off and attached a spark tester to another spark plug. and recorded the readings below.
Cyl1 | Cyl2 | Cyl3 | Cyl4 | Secondary Ignition With Spark Tester |
7 | 16 | 6 | 9 | Firing Voltage (KV) |
6.40 | 6.16 | 7.04 | 5.65 | Burn Time(ms ) |
The gap we put was between 5mm - 30mm,
- The reading clearly shows that it takes more firing voltage to fire the spark over to the other side.
- in comparison the burning time increases .
- below is a comperd picture of the jumping spark and the normal ones.
