marshg246
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- Jul 12, 2015
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I suggest that my customers break, clean and re-make all electrical connections, check battery and charging system.
Consider this little drawing:
Very simplified - I know coils are not the same as resistors and I know there is some voltage drop in the Tri-Spark.
If the battery has 12.8 volts and each coil is 1.6 ohms then the combined coil resistance is 3.2 ohms. Therefore by Ohm's law Current = Voltage/Resistance = 4 amps. The voltage across each coil is Voltage = Current * Resistance = 6.4 volts and we're happy.
Now consider that the connector has built up a little resistance over time and it is now 1 ohm. Now the combined coil and connector resistance is 4.2 ohms. Therefore the circuit current is 3.05 amps. So, the voltage across each coil is about 4.88 volts and the voltage across the connector is about 3.04 volts.
Let's say that the coil normally produces 20k volts at 6.4 volts across the primary. At 4.88 volts, it will only produce about 15.25k volts! Not happy.
The sinister part is that the connector resistance builds up slowly over time and at some point, the connector starts getting hot which causes it to build resistance even faster.
I showed one connector, but in reality, in the coil circuit, there is a connector at the Tri-Spark, the other end of that wire either goes directly to the coil or to a connector with a wire that goes to the coil, there are four connectors on the coils and one of those goes to ground. Tiny resistances in any or all of those add up.
The other important circuit has several connectors and the kill switch - this is what feeds power to the Tri-Spark for its electronics.
BTW, this is not only Tri-Spark, it is all ignition systems.
As RoadScholar said, break, clean, and re-make connections. Personally,I clean the bullets with WD40 and use new bullet connectors. IMHO, the bullet connectors from British Wiring (https://www.britishwiring.com/) are superior to the originals - they are much harder to plug in as they are made of heavier metal.