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Light Speed Plasma 111 Issues

Tsabean

Active Member
Asking for a friend. He is installing the electronic ignition system (2 CD boxes/4 coils) on a new a Titan 340 engine. The engine was built up at a local shop and was successfully test run using the Light Speed boxes.
With the engine installed in the aircraft, he can only get a spark from one position on the CD boxes.

He states-“When I try to do the phasing procedure and rock the prop back and forth at TDC/BDC, I only get spark across the tower of one coil. If I swap the primary ignition wires around the 4 BNC connectors on the CD boxes, I consistently get spark on whichever coil is attached to just one of the four.
Similarly, if I swap the input 15 pin connectors between CD boxes, I get the same result. To complicate things, I have, on rare occasions, got a weak spark from coils attached to two other BNC connectors.
Anyone else experience issues like this with Light Speed?”

Cheers, Tom
 
Check Power & Switch states:

Verify the ignition controllers are powered on and receiving 14 - 28Vdc; measure voltage at INPUT connector on the HARNESS, pin 7 & 8.
Verify the voltage on the ignition controller OUTPUT connector, pin #14; should be ~14Vdc.

If using a key-switch with START option (ACS-510-2), verify that the R-GND jumper is removed. If this jumper is installed, the "Right" ignition system will be disabled during start -- this isn't a needed feature with the Plasma III; hold over from the Dual Magneto, 1 impulse coupled, days...

Check Coils:

Measure the resistance across the high tension "towers", similarly measure the resistance across the spade inputs.

There should be about 1ohm between the primary spade inputs, and a bit more as I recall between the towers.

Measure the resistance between each primary and each secondary -- all should indicate an OPEN circuit. Any other indication means the coil has failed.

Check Phasing:

For the ignition box connected to the "Top Sensor", output A should go to Coil A-1, output B should go to Coil B-1.

For the ignition box connected to the "Bottom Sensor", output A should go to Coil B-2, output B should go to Coil A-2.

Coil A/1 should be wired to Cylinder 1 & 2
Coil B/1 should be wired to Cylinder 3 & 4
Coil A/2 should be wired to Cylinder 1 & 2
Coil B/2 should be wired to Cylinder 3 & 4

"Click" test:

Disconnect all leads & turn fuel off. Find TDC for #1 cylinder. Ignitions, ON - rock the prop & flywheel about the TDC mark - you should see/hear the coils attached to Cylinders #1 and #2 fire. Rotate to BDC and rock, you should see/hear the coils for #3 and #4 fire.
 
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I hope he realizes that a 4-cylinder 4-stroke engine fires every 180 crankshaft degrees, which means that to get the other coil to fire, you need to rock the crankshaft at 180 deg from TDC #1 cyl.
 
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