Oscilloscope Patterns (WS3)

Ignition Primary

Battery voltage come into the coil. At (A) the coil gets grounded and the magnetic field is created across primary windings.

B - As the coil was ungrounded the magnetic field collapsed across the primary windings making a voltage spike of 300v.

C - This is the burn time or spark duration

D - coil oscillation. this is the oscillation between the primary and secondary winding.

Petrol Injector

A - this is the supply to the injector which is the battery voltage.

B - This is when the injector is grounded and this is the time the injector open to spray fuel

C - This is the injection time. This is the time the injector stays open and injects in the fuel.

D - The injector is ungrounded which closes the injector. This causes the magnetic field to collapse in the injector windings and voltage spikes up to 45V.

E - The voltage goes back to battery voltage.

Oxygen Sensor

This  is a zirconium type oxygen sensor  and it is in closed loop and is cycling. At (A) the voltage is high to 0.9v this indicates a rich mixture where there is less air in the exhaust. The signal goes to the ecu telling the fuel mixture is rich.

B - the voltage goes down to 0.2v. This tells us that the air fuel mixture is lean. The oxygen sensor detects high amount of air in the exhaust. This voltage goes to the ecu indicating a lean mixture.

RPM (crank)

A - reluctor tip is getting closer to the coil therefore air gap gets smaller and the magnetic field is increasing.

B - Air gap is smallest here and full magnetic saturation of the pickup has reached. The reluctor is lined up with the coil.

c - As the reluctor moves away magnetic field collapses across the coil and induces a voltage in the opposite direction. Back EMF.

D - reluctor tip moving away from the coil so voltages goes back to 0v.

E - Peak to Peak voltage (2.2v)

Hall Distributor

A - This is the dwell time. This is the chopper plate is is cutting the magnetic field. The voltage gets high.

B - when the chopper plate moves away from the magnets, the circuit gets grounded so the voltage goes to 0. This is the firing time of the coil.

Cam Position Sensor

A - The reluctor wheel is getting closer to the stater the magnetic field increases therefore voltage is increasing.

B - As the reluctor wheels moves past the stator, the magnetic field collapses and voltage is induced in the opposite direction.

C - showing the wheel moving away form the stator and voltage is getting back to 0.