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How to Bench Test a 123ignition

Bench Testing a 123 Ignition

Now that you have the 123 loose here is a simple test to see if it is working.

1.) Connect a red and black wire to the + side of a 12v power supply.

2.) Connect the red from the power supply to the red on the 123.

3.) Connect the black from the power supply to one side of a light bulb and run a black wire from the other side of the bulb to the black on the 123.(See illustration)

4.) Connect the Blue wire to the negative side of the power source.

bench-test-illustration-1.gif

While you turn the axle the bulb should flash shortly each time the LED turns on.

For Switched models

 

1.) Connect a red and black wire to the + side of a 12v power supply.

 

2.) Connect the red from the power supply to the red on the 123.

 

3.) Connect the black from the power supply to one side of a light bulb and run a black wire from the other side of the bulb to the black on the 123.

 

4.) Connect the negative side of the power source to the body of the 123

 

Some Suggestions to check

-the +12V of the red wire is not connected on the coil +12V and this point gets interrupted by the ignition key when the starter is engaged

-bad connections in the wires and or high resistance in the ignition key lock*)

-bad grounding of the 123 unit *) in the engine block (I suggest using the M6 hole to attach an extra ground wire to the block)

-the spring loaded center graphite contact has fallen out of the distributor cap or is stuck in its hole and its spring does not push the pin against the rotor arm

-spark-plug leads or and or coil that with not enough isolation *)

 

*) Due to automatic coil current control and faster charge of the coil, peak currents in the low voltage circuit are higher and resistances can cause problems. The higher spark voltages in the HT circuit require better isolation in the HT leads and coil.