WS8

Firing voltage : the voltage (push) that is needed for the spark to jump the spark plug gap.

Burn voltage : the voltage need ed to maintain an arc between the spark plug electrodes so it can burn all of the fuel in the combustion chamber.

Burn time : the length of time which the arc is maintained between the spark plug electrodes

this is normally used to check the secondary circuit components eg. spark plugs , HT leads , secondary ignition coil, distributor cap , rotor and king lead .

Dwell time : the length of time which the primary circuit is grounded (turned on) before each cylinder firing so it can build strong enough magnetic field so then secondary winding can create a strong enough spark to jump the spark plug gap .

Primary Ignition Pattern : It is a very good way to check our primary ciruit and also to see firing voltage and burn time ... the higher the firing voltage the shorter the burn time this uses string theory so as the firing voltage decrease our burn time inceases .

Secondary Ignition Pattern : This pettern is a reflection of the primary ignition and has the same charactristic , its produced by the primary circuit collapsing on its self and inducing a voltage very similar to the primary pattern but the firing voltage is lower . After a snap acceleration we can see the firing voltage decreases and burn time increases which proves the string theory.

Toyota corolla FXGT 4AGE

All of these readings are normal ( checked against manufactorer spec)

We can see here as I am flicking thru all 4 cylinders that they are very similar and if there is an odd one then we know there is a problem with that spark plug , lead ... a very good way for diagnosis.

We can see in the above video dwell time increases as the engine RPM increases , this is so that it still can provide a strong enough spark due to the coil being earth out earlier before the cylinder reaching TDC in the compression stroke.

In the table below we can observe the string theory in action ... as the cylinder 4 has been grounded to the body the firing voltage decreases because it does not need as much voltage as in a sprark plug but this causes the burn time to increase

Again we can see in the table below that because the gap in the tester is smaller than the spark plug gap then firing voltage has decreased , the burn time has increased