Electrical Gremlin

I picked up a new wiring harness off e-bay and swapped out the one I had on my 1980 Xj650. the previous owner had all sorts of questionable splices and blinkers, headlights,etc. didn't work. After installing the new harness, i herard a "pop". I thought I had shorted out the ignitor. Everything worked electrically except no spark. I cleaned all the connections with contact cleaner and was able to get spark in #1 and #4 , but still have no spark in #2 and #3. I tested the coil and it tested to specs. I tested the wires going to the coil while the bike was running and it showed power. Could the ignitor be partially shorted? Or maybe the pick-up coil? Any suggestions? All the relays appear to be in order.

 

Pop and no spark, not a happy combination. At first blush, I'd say you need to make sure that the harness you got matches the bike, connector by connector. 80-81 harnesses are different than 82-83. Use the wiring schematics in the manual to compare each and every wire and connector (not as daunting a task as it might sound).
Then you need to ensure that all of the ignition components are connected to the right connectors. If you verify all things are correct, then I would chase a dead component.
If a pickup coil failed, you would see at least one side firing.

 

Thanks Robert,
The harness was off another 1980 and all the connecting harnesses are connected right, I removed and replaced as I installed the harness. They say you're the man to see when you have an ignitor issue. Is it possible to partially fry the ignitor, where only one coil will fire?

 

Yes the TCI can loose one side (it's not an ignitor). There are two output switching FET's (Big 'ol honkin' transistors) that handle each side. I've had one TCI pass through that had one of them fried.

 

Congratulations Todd, you blew out the #2-3 output transistor, AND HOW! I've never seen one blown apart like that. I'll have to post some photos. I should have this thing buttoned up in a day or two and headed back to you with new parts.

 

Cool, at least you found the problem.....unless it was another electrical problem that caused it to blow. Any suggestions on how to check for any other issues before I plug in the repaired TCI. I don't want to do it all over again! The harness from the Generator (3 white wires) was replaced with bullets connecters. I had previously posted this on a chat forum and was told the order of the 3 wires did not matter. Do you think this may have been why the transistor blew?

 

Those particular three wires can be installed in any order without detriment. You need to ensure that you are getting the correct voltage at the coils. If you see more than 12~13 volts at the coils, I'd worry. You can check for pulsing with an analog meter. BTW, I'll be in Norwalk this Saturday helping another forum member, I've my garage Haynes available for you to look over if you need some guidance.