Standard TCI ignition. Spark only on one cylinder

[suntrakr]

Currently not getting an spark on the left plug. Testing with a spark tester and right side has a nice and healthy spark but left side not getting any current at all.

Faulty coil? Rotor magnet/TCI Pickup issue. Don't imagine it's a magnet/pickup issue as I'm getting a good spark on the left and they fire off from the same trigger.

Any suggestions on diagnosing and where to start?

 

[TwoManyXS1Bs]

Currently not getting an spark on the left plug...
... I'm getting a good spark on the left ...

???

Must be the spark plug...

 

[fredintoon]

Currently not getting an spark on the left plug. Testing with a spark tester and right side has a nice and healthy spark but left side not getting any current at all.

Faulty coil? Rotor magnet/TCI Pickup issue. Don't imagine it's a magnet/pickup issue as I'm getting a good spark on the left and they fire off from the same trigger.

Any suggestions on diagnosing and where to start?

Hi suntrakr,
the TCI ignition has only one of everything except that the single coil has two plug wires and two sparkplugs.
My simplistic understanding is that the spark current goes down one wire, sparks that plug, goes through the head, sparks the other plug then goes back up the other plug wire.
First, try laying both plugs on the head and kicking the engine over.
My first "usual suspect" would be a faulty plug.

 

[XSLeo]

Faulty plug, then plug cap, then wire.
Leo

 

[suntrakr]

Thanks all, gives me clarity. Sounds like easy resolution. Will test.

 

[angus67]

Faulty plug, then plug cap, then wire.
Leo

cant change wire on stock tci coil. its glued in. but you can take the plug cap off, and snip a 1/2 inch from it, and put the plug cap back on. Try that first.

 

[suntrakr]

Tahnks @angus67 but how is taking 1/2 inch off the plug lead going to help?

 

[angus67]

If the copper at the end is corrode, or making weak contact, it will give u a fresh end. The cap just unscews. There's a pointy spike in there

 

[5twins]

To insure good contact, I like to prep the ends of my spark plug wires like so .....

Clip about 1/4" off the end of the old wire to get to some fresh stuff. Strip another 1/8" off the insulation and fan the strands of the core wire out as above. I also put a little dielectric grease on the wire end before screwing the cap on.