Ignition System Troubleshooting

[ksatter26]

Re-examining the panel wiring because of the engine startup problems documented elsewhere in the Build Log.

I seem to have the new CDI/Relay/harness re-installed properly(?). However, the starter kicks over as soon as I hook up the battery. Seems to by-pass the master power and starter switches. The good news is that I have SPARK which was the initial problem all those months ago.

I verified that the green/yellow wire from the relay bundle is connected to one side of the motorcycle push-button starter and that the other terminal goes to a solid chassis ground (cylinder-head bolt). I tried taking the starter switch out of the circuit and STILL the starter motor kicks over as soon as I connect the battery which indicates to me that the circuit is being grounded elsewhere.

I'll try chasing that down from the panel side and document the circuits with a schematic .... again.

More later.

[LA F2 Flyer]

Kurt you were asked to add an extra wire to the new relay when connecting it...as I recall Polini was unable to provide too much info in regards to why the wire was added (or am I misremembering)? I wonder if any harm would come from trying it WITHOUT that "new" wire connected.

[ksatter26]

Tried removing the grounding wire that I added from the starter motor mount to the CDI bracket and thence to the cylinder head bolt. I really thought that was providing the erroneous starter ground that is causing the problems. No joy. starter still kicked over when I hooked up the battery.

I did find that the starter switch was grounding when supposedly in the open position. I replaced that push-button switch with a new normally OPEN/momentary CLOSED switch ... also no change.

London Ivy (Tampa 303 help) suggested that I remove the connections to both relay pins 85 and 86 and try connecting the battery. If the starter still turns over, this would indicate that the relay is bad. This proved to be true (3rd relay). He also provided me with a link to a source (on Amazon) for the normally open, 12vdc/200A relays that he uses. The COBO relays are ~$40! The AutoZone equivalents are ~$18. The Amazon relays come 2 to a pkg ~$8 each. I placed the order and expect them tomorrow. Fingers crossed .... again.

As an aside ... Google searches find NO Polini Service shops listed.

Amazon: Hamolar 2 Pack 12vdc/200A, 4 pin relays ...

[LA F2 Flyer]

I was just about to post the same thing after reviewing your pictures again. The image on the relay itself would suggest that the big wires are for the starter (hence the large gauges) and the small wires trip the switch.

I believe the easy way to test the relay would also have been to remove it and check resistance across the fat wires. Minimal resistance would indicate a complete circuit. It certainly sounds like you found the issue if my minimal knowledge of circuitry is serving me right now.

[Badland-F5 Pilot]

I was just about to post the same thing after reviewing your pictures again. The image on the relay itself would suggest that the big wires are for the starter (hence the large gauges) and the small wires trip the switch.

I believe the easy way to test the relay would also have been to remove it and check resistance across the fat wires. Minimal resistance would indicate a complete circuit. It certainly sounds like you found the issue if my minimal knowledge of circuitry is serving me right now.

Agreed,
Pin 85 – lightweight wire to the ground of the aircraft
Pin 86 – lightweight wire to the positive of the battery.

Put normally open, push to close switch in the wire to pin 85 or pin 86 will work, though good practice if I remember correctly is to put the switch (fused) on positive wire to prevent the circuit from closing if a short is made after the relay.

Pin 87 – heavyweight wire (fused) from the positive of the battery.
Pin 30 – heavyweight wire to the starter.
The starter of course is grounded to the frame or back to the negative on the battery.

Does this sound right?
Todd