coil problems

[tpr1035]

1980 xs 11 special; No spark on cyls 1 & 4. Repaired the pickup coil wires, changed the coils, still nothing on 1 & 4. Anyone have a suggestion?

[BA80]

You checked the pickup coils with an ohm meter at BOTH connectors?

There is one behind the fuse panel (5 wires) and one at the TCI (4 wires).

[motoman]

You checked the pickup coils with an ohm meter at BOTH connectors?

There is one behind the fuse panel (5 wires) and one at the TCI (4 wires).

Good advise.........and they all need to be unplugged and cleaned, no matter how they 'look'. 'Look' clean don't cut it.

[tpr1035]

pick up coils

Please explain 'both connectors" Where would I find them? And am I checking for continuity, meaning the coils do not have any opens?

[motoman]

Please explain 'both connectors" Where would I find them? And am I checking for continuity, meaning the coils do not have any opens?

'both connectors'.........re-read BA80's second statement.

[BA80]

Please explain 'both connectors" Where would I find them? And am I checking for continuity, meaning the coils do not have any opens?

As I said, one behind the fuse panel, it has 5 wires. 4 pickup coil wires (2 for each coil) and a green one in the middle that's for the neutral indicator light.

There is a 4 wire connector that plugs directly into the TCI. This is the other end of the wires from the connector behind the fuse panel.

Yes, you are checking for continuity in the pickup coils coils and the wiring to them. You will also be checking for the correct resistance in the pickups themselves. resistance should be around 750 ohms give or take 50 in each pickup coil. It needs the resistance to create the millivolt signal to send up and tell the TCI when to fire each coil.

Also, when you have the ohm meter connected to the pickup wires, move the wires that are under the left cover. If you still have a broken wire there it should show up on the meter then by the reading fluctuating or dropping out and back in.

Clean and tighten those connectors, and all connectors for that matter. Corroded connectors or connections are the biggest cause of electrical issues on these 35 - 38 year old bikes.

[TopCatGr58]

Hey there,

Great info from Greg and Brant. Just a followup regarding further diagnostics.
As you stated, you say you swapped the wires/changed the coils...so I'm assuming that you swapped 1-4 coil with the 2-3 coil as well as the plug wires along with the triggering wires...grey/orange at the coils connector so that the TCI would still be triggering the correct coil for the correct cylinders?

SO...IF your PU coils meter out correctly, and with swapped swapped coils you stay you are still NOT getting fire on the coil that is now controlling 1-4 cylinders...even though it was the 2-3 coil....and that the coil NOW on the 2-3 cylinders which was previously the 1-4 coil...and it IS getting fire...then you have now confirmed that the actual spark plug coils ARE working. You are able to get fire from both coils, but the same cylinders are still missing fire...this points to the actual TCI.

The TCI connectors can also go bad due to corrosion and poor soldering as well as just aging of the soldering. There's a tech tip about RESweatting the solder connections/joints IN The TCI where the PCB connects to the external connectors that go to the connector pins. You do NOT need to remove the PCB from the TCI case.

Now...IF the coil you swapped was bad and the PU coil and TCI was good, then you would then loose fire in the new 2-3 cylinders instead of staying with the 1-4 cylinders...that would then indicate the actual spark plug coil as being bad/faulty...provided you have ruled out corrosion at the plug wire to plug cap connection as well as the built in resistor within the plug cap....both can cause enough resistance to prevent firing despite the coil being still good!

Good luck, keep at it.
T.C.