Need help solving this problem

I'd be thinking the coil might be bad before the TCU. Swap the coils over first to see if the problem follows the coil to 2 and 3. If it follows - bad coil. If it stays with 1 and 4, then you either have bad plugs (even new ones can be bad) or a TCU problem.

Good luck!

 

I replaced all 4 plugs when I first noticed the problem, also the cylinders (1&4) look to be on separate coils

 

If 1 and 4 are on separate coils on your bike you will have major running problems 8O

Have another look.

 

When I say coil I'm talking about one of the two things under the tank where the ignition wires attach two. Is this correct?

 

Yes. 1 and 4 should be on one of them, and 2 and 3 should be on the other one.

 

That's not the way it is on the bike right now, I've ran it all summer though and never had any problems?

 

Time for pics

 

Doh! I don't really feel like taking the tank off again :/

 

Paint magic

 

You got that wrong, Boss 1+4--------- 2+3

 

+1 it's wrong for sure the way it is. Are you sure you didn't mix it up when you changed plugs?....

 

Double checked tonight and you two are right about the wiring, it's how you described.

Both coils are good

Fuel supply good

Must be the TCI unit

 

Don't rule out the possibility that some of your new plugs might be faulty - I've come across this a few times.

Also - how have you checked your coils? Have you swapped them around to see if the problem follows the coil?

Best to do the cheapest / simplest checks first before you buy another TCU.

 

I used a multimeter to come to my conclusion

Same ohm reading with both coils

But when checking the voltage of the wires going to each coil,

The coil with the cylinders firing properly read 12V

The coil with the cylinders not firing read 0V

So the one coil isn't getting any power

 

Either the pickup coil is bad for that bank or the TCI is hosed. Ohm out the pickup coils and pull the cover off of the TCI to see if any of the solder leads are cracked.

 

If this is the same basic ignition system as in the SECA 750, then the problem is probably not the TCI unit.

The 12V to the coils doesn't come from the TCI unit, it comes from the battery through the ignition fuse. One fuse is shared for the two coils, so it can't be a bad fuse. The TCI unit grounds the other pin on the coils to charge them, and releases the ground to fire the coil. If the TCI unit was shorted (pulling the pin to ground all the time), it would quickly blow the fuse... so, again, it doesn't sound like the TCI unit is bad, it sounds like the wiring going to the 0V coil is bad.

Jumper the 12V side of the non-working coil (through a 5A fuse) to battery plus and see whether you start getting spark.

Paul

 

One of his ignition pick-up coils could be bad, or a pinched wire lead from it to the TCI.............

 

Well after double checking everything again tonight it's the coil. Good news in my opinion because it beats buying a different TCI

Had one from the parts bike that worked, only I found it was for the cylinders 2&3 thus the wires are too short

 

I'm pretty sure I read, in another thread, that chacal has a tool to make splices on factory coils to add new wire.

You should check with him to confirm that thought

 

Folks, I don't think there's any saving the OEM Coils from the ravages of Time.
As they turn 25 years old ... many start giving-up the ghost.

Getting-on with them as they get old is a crap shoot.
They might be OK for another season or two; but I think we should all be getting ready to bid farewell to these OEM Coils just like many of us have already bid farewell to the Fuse Panels.

With that in mind, buying Coils off eBay that came off a bike as old as ours are might not be the wisest thing to do.
They are getting as old as the one we got.