Coil question/problem...

[natemoen]

I was testing the coils this morning and I get 1.5 Ohm at the at the primary on both but I am not getting anything when I check the secondary. The bike was running (not great but it was running) before I pulled the wires to check (and no I have not yet put it back together to see if it is still running. It is the original coils and the PO had spliced in new connectors and boots about mid way between the coils and the boots. I am going to put the plugs back on and see if there is still spark from them or of I broke the splice when I pulled them off. Anyone else have any other Ideas??

Nathan

[dbeardslee]

When you checked your secondary resistance, did you try it with the plug caps removed and the probes inserted directly into the ends of the high tension wires? Also, make sure the wires you're putting probes into both go to the same coil. Also, the primary resistance should be checked at the TCI. Remove the 4-prong connector, hold it so the 'slots' are horizontal, insert a probe in each of the 'upper slots', set dmm to the 200 ohm range, and take a reading. Repeat for the 'lower slots'. Readings should be about 3.3 ohms at the TCI. If you're getting that 1.5 ohm reading at the TCI, it's too low.

[natemoen]

When you checked your secondary resistance, did you try it with the plug caps removed and the probes inserted directly into the ends of the high tension wires? Also, make sure the wires you're putting probes into both go to the same coil. Also, the primary resistance should be checked at the TCI. Remove the 4-prong connector, hold it so the 'slots' are horizontal, insert a probe in each of the 'upper slots', set dmm to the 200 ohm range, and take a reading. Repeat for the 'lower slots'. Readings should be about 3.3 ohms at the TCI. If you're getting that 1.5 ohm reading at the TCI, it's too low.

Yes I checked over and over to make sure that i was using the wires from the same coil. I put the probes into the plug caps to check it and I never got a reading. When I did the primary I got 3.3 at the TCI and 1.5 for each coil individually when I check them at the connectors by the coils themselves.

When I put the plugs back on the wires I get spark. I didnt crank it long enough to look that close at the spark so dont ask how it looked cause the thing fired up with only 2 plugs in.

[dbeardslee]

On 30-year-old coils it's not unusual to find that your high tension wires are toast. When I first upgraded my coils, I thought I would keep the old ones - just in case. I was going to store them in a 3-pound coffee can, but when I bent the wires to put them in the can, they snapped clean in two. Your coils sound like good candidates for a high tension wire graft - or a new set of hot coils.

[natemoen]

Most likely going to buy a new set of coils but I really didnt want to. I am just curious how I am getting spark but when I check the resistance on the coils I dont register anything?

[dbeardslee]

Might have something to do with 15k volts when the coil fires, vs what a multitester can put through the wire. You can always pull the plugs and lay them on the valve cover and hit the starter. That way you can see what kind of spark you're getting. You can also fire it up in a relatively dark place, and throw some water on the high tension wires while it's running. If you see sparks arcing from your high tension wires, you'll know they're bad. That's just another test though - the multitester doesn't usually lie. If that's all that's wrong with them, it costs about $12 for new wires, and it's not that hard to do. But newer, more powerful coils sure are nice.

[b.walker5]

Are you using an Autoranging Meter or do you have to manually select the measuring range, and are you measuring the secondary correctly? Page 168 of Clymers tell us that you measure the Primary resistance between both primary terminals at the coil and your looking for 1.5 ohms +/- 10%, no argument there, BUT over the page on 169 it tells us that you measure the secondary resistance between both PRIMARY leads, and your resistance should be around 15K ohms. THIS IS A MISPRINT and should read between both SECONDARY leads. Figure 26 shows the correct procedure.

If you've already picked up on that then make sure your meter is switched to a range that will show K ohms. If its not auto ranging and your on a lower scale it may not register.

[natemoen]

Are you using an Autoranging Meter or do you have to manually select the measuring range, and are you measuring the secondary correctly? Page 168 of Clymers tell us that you measure the Primary resistance between both primary terminals at the coil and your looking for 1.5 ohms +/- 10%, no argument there, BUT over the page on 169 it tells us that you measure the secondary resistance between both PRIMARY leads, and your resistance should be around 15K ohms. THIS IS A MISPRINT and should read between both SECONDARY leads. Figure 26 shows the correct procedure.

If you've already picked up on that then make sure your meter is switched to a range that will show K ohms. If its not auto ranging and your on a lower scale it may not register.

There is only one setting for Ohms so I am assuming it is an autoranging meter.

[b.walker5]

Sounds like it, try replacing the meter batteries. It needs voltage at the probes to measure resistance and in the higher range it may not have enough. Alternatively, try another meter if you can.

Be warned that any discussion about meters here may create a debate over the merits of analogue meters over digital. Personally, I have been an electrician for near enough to 35 years and I have a foot in both camps, but for what your doing a digital is fine, as long as it's a good one. Cheaper ones can give misleading and incorrect readings some times.

[bikerphil]

I've had similar problems, coil works but gives no reading when tested. Upgrading the coils was a no brainer.

[natemoen]

Is it really possible or even a good idea to splice a new piece of wire into the middle of the high tension wires. That is was the PO did. I know one of the wires is loose (it actually came off at one point). I might try putting new wires on the coil like it says in that tech thread. If that doesnt work I guess I will have to bite the bullet and get new coils.

[dbeardslee]

Is it really possible or even a good idea to splice a new piece of wire into the middle of the high tension wires.

It's probably possible - hardly seems like a good idea. On the factory coils there's a sheath over the high tension wires. Is that what you're talking about?

[natemoen]

It's probably possible - hardly seems like a good idea. On the factory coils there's a sheath over the high tension wires. Is that what you're talking about?

The PO cut the high tension wires about 3 - 5 from the coils and then somehow (not sure how) spliced in a new chunk of high tension wire to go to the caps. There is also a piece of what looks like some rubber hose RTVed over the splice area.

I know there is a sheath over the original wires and a good chunk of the sheath was removed and not replaced when he did this "splicing"

[dbeardslee]

Man, that sounds like a real hatchet job. Probably found your problem, though - at least one of them . Can you post a pic?

[natemoen]

I will try and put some pics up tomorrow.

The funny thing is though is that I still get a nice blue spark from the plugs...