Hi New member with ignition woes (TCI)

[justinc1081]

Hi there, i have been working on my bike for a while now getting it back to road ready condition, im having some issues with keeping spark on all 4 cylinders. I have done the pickup coil repair from this site and that helped with the resistance on one side. I am getting consistent fire from right side coil which fires cyl 2,3 but usually nothing on left coil for cyl 1,4. I checked with volt meter and there is 12v on both the orange and gray wires. However when cranking the volts on gray (right side, working) drop down and fluxuate down to around 7-8 volts, the orange (left side, non working) only drops to just over 10 from 12volts.
This was all working about a week ago, then put in rebuilt carbs and ran for about 5 minutes before there was a no spark on any cylinder issue.
Before i explore eBay for a new TCI unit is there a test i am missing that i can perform. Thanks in advance for any help, this site has already provided me with a lot of information in getting her back on the road
Also i think my father (previous owner) may have changed the ignition coils as they both Ohm'd out to 3 ohms resistance on low side, manual says 1.5
1980 xs1100 SG
(removed octy) all stock

[natemoen]

Have you went through the bike and cleaned all the electrical connections? If not better start doing that first. Most likely you just have some dirty connections and that is where the voltage drop is coming from.

[justinc1081]

Cleaned some as ive been going along, seems like the electrical gremlin is moving around on me There was some issues with the pickup coil wires and now that is resolved. Ill be going thru all the connections and fuse box most likely today. Interestingly enough last night i turned the bike over and there was spark on all 4, i moved the tci box and tried again and back down to 2, there may be some short on one of the wires or loose connection somewhere...

[DGXSER]

It is not uncommon for there to be issues with the pin solder points coming loose and needing to be resoldered.

[GLoweVA]

Here's a thread that talks about the pin connections on the TCI:

http://www.xs11.com/forum/showpost.php?p=390226&postcount=14

[justinc1081]

well im back to no spark on any coil, i do believe this tci is a dead goose. Tried to re-solder some of the connections but this made no difference, all the voltages and resistances going into the TCI are correct, i even have 12v at the red/white connector going to the coils. So either both coils went kaput at basically same time or the TCI is on the frits.
I had tested each coil individually when i had spark and both worked when plugged into the gray wire. At this time no spark at either coil.
Checked fuses of course any cleaned all connections with QRC cleaner and sandpaper.
THanks for the help, im going to look on ebay for one and give that a shot

[dondons1984]

have you checked the connection boots that connect to your spark plugs? sometimes (as my bike was) get corroded and wear. screw them off clean both the female and male ends and reattach. See if that helps.

Eliminate the cheap first then go for the expensive. No point in buying a TCI if it is just bad coil connections to your SP.

Greg taught me this one. Or should I say motorcycle god. lol

[TopCatGr58]

Hey Justin,

Let's back up a bit. You stated that the primary resistance of the coils was ~3 ohms, not the 1.5 you expected if they were stock. The Tci likes and needs to see 3 ohms, but doesn't care how it's there, either with 1.5 ohm coils AND 1.5 ballast resistor.....or 3 ohm coils...and no ballast resistor.

Which brings me to my question....do you still have the Ballast Resistor on the bike/harness and still connected instead of bypassed? When you are trying to start the bike, the TCI bypasses the Ballast resistor and sends the full 12 volts to the coils..that's why you are seeing 12 volts on the red/white wire. Measuring the voltage on the grey/orange wires is after it's gone thru the coils, and so you should see a voltage drop on them since it has 3 ohms of resistance going thru the coil.

SO...if you do have 3 ohm coils, AND the ballast resistor is still INLINE that could be a reason for getting weak spark when running. However you should be able to start the bike because of the bypassing feature of the TCI during starting.

Also, you could have asked if there were someone near you that could loan you a TCI for your testing processes before you actually spent the $ for a replacement TCI.

T.C.

[justinc1081]

Come to think of it yes the silver ballast is still in place, i will go remove that out of the equation real quick and let you know. I have not bought anything yet, anybody in Springfield MO area?

[justinc1081]

Wish it were that simple lol, no ballast and still nothing on either coil

[natemoen]

If it is intermittent like you describe it is not going to be a failed tci. If it was the tci it would burn out and be done, not work sometimes and sometimes it doesn't work.

You have some connection or joint somewhere that is not making good contact and you need to trace that down and fix it. Buying different parts is just going to lighten your wallet. Figur out what is wrong first, then decide if you need a different part.

[BA80]

I had a similar problem with Rockin'D's bike when we were working on it. If it was cold out it had no spark but if you cranked on it long enough it would start on 2 cylinders then pick up the other 2 after a minute or so. If it was above 50 it would start right up fine.

Drove me nuts.

It ended up being a weak signal from the pick up coils. Normally pick up coils will ohm out at around 750 ohms, the ones that were on there only ohmed out at around 650 ohms. Swapped out the pick ups for a set with the proper ohmage and DONE. It hasn't stuttered since.

If there's power to the coils and the coils check OK then they aren't getting the signal to fire. The signal comes from the TCI which get's it's signal from the pickup coils.

[justinc1081]

Ya the pickups are both ohming out at 768 now, i had to repair 2 of the wires. With TCI plugged in voltages are correct on the pins orange, gray, red/white and black/white 12v, 12v, 12v, and 6v as per manual. Ive lost all spark and it hasnt come back. I tried to re-solder some of the connections inside the TCI and this may have made it worse
12v at the red/white at the ignition coils. I know this is a gamble to buy another tci but considering the bike was free im not too far monetarily invested just yet. Ill post back in a few days when the replacement part comes in.

[GLoweVA]

It sounds to me like either the pickup coils aren't giving the TCI the signal to fire, or the TCI isn't firing or there's a problem with the coils/plugs.

The manual talks pretty in depth about how the TCI/pickup coils work and what to check as far as voltages and ohms. Sounds like you've covered most if not all of that.
So.....
Maybe you can check the output of the pick up coil wires with a ohm meter while cranking the motor and see if the reluctor is 'triggering' the pick up coils?

If you see something there, then maybe you can check the output of the TCI and see if the transistors are 'firing' (shorting to ground) thus discharging the ignition coil's field.

If that's happening, then the secondaries of the ignition coils should be discharging thru your spark plugs. Have you checked the gap on them? Could they be bad? (I know what you're thinking... all 4?!?, but you've got to rule it out)

[ManagerMike]

There is a test I've performed countless time on pick-up coils on automotive applications in addition to resistance check, It should translate here, never had a need to try it. Test the output of the pick-up coils for an A/C signal while cranking the engine, rule of thumb automotive wise is 1 volt A/c at cranking speeds is good. Less than .7 volts is too weak for the Ign module to sense.

Again I don't know if the values I'm familiar with translate, but if it were mine and I saw a volt or more ac at the TCI and had all the rest of the input voltages and grounds I would condemn the module.

Maybe someone else could chime in on this, have tested in this manner?