Problem with Secondary ignition...

[Squeaky]

I have read these posts with interests because I have the same problem. Any answers or insights would be very helpful to me! My Aerovee would not run at all, now runs rough on secondary ignition. Primary ignition runs good. It has 10 hrs TT before I bought it used. Coils check good with ohm meter but don’t see any activity at either trigger. Ken

[gammaxy]

If you have EGT on each cylinder you can usually tell which ones aren't firing (this helps if the problem is specific to a trigger or coil). From your description, I'm not sure how you tested the triggers, but if you really don't have any activity at either trigger, it shouldn't run at all.

Do you have a copy of the Aerovee manual? I'd go through the section about the secondary ignition and make sure everything looks right, especially the timing of the magnet.

In my experience the coils and triggers fail more often than I'd like and can be difficult to diagnose with a multimeter. Often, the failure happens at high voltages and maybe temperatures. It's often easier to just replace with new parts. But, with only 10 hours, I'm more suspicious of installation issues.

[Bryan Cotton]

I have read these posts with interests because I have the same problem. Any answers or insights would be very helpful to me! My Aerovee would not run at all, now runs rough on secondary ignition. Primary ignition runs good. It has 10 hrs TT before I bought it used. Coils check good with ohm meter but don’t see any activity at either trigger. Ken

Did you check for spark? Check timing? Would be helpful if you listed what you have done so far.

[Squeaky]

Thanks Bryan and Chris! Coils both read 1.9 ohms across primary windings but it says they are 3 ohm coils. Secondary windings are both 13.3 kohms. Triggers both read battery voltage at coil yellow wires when magnet is not aligned under trigger.

[Squeaky]

Voltage does not change when rotating prop - at yellow wire that is.

[Squeaky]

Also it does run on secondary roughly at idle. I haven’t tried higher speeds or noticed EGT. The first thing I changed was rotating magnet cap 180 degrees.

[gammaxy]

If you haven't already, check out page 45 of the Aerovee manual: http://www.aeroconversions.com/support/ ... Manual.pdf

It's not clear if rotating the magnet cap 180 degrees was just a guess, but the manual will confirm whether you have it correct now (by comparing to the primary ignition magnet).

I don't recognize the yellow wire you mention. I think the old triggers had 3 wires, one of them being orange. The new triggers seem to only have two. Because of this, I can't really comment on whether your measurements seem correct. Also, I think these sorts of measurements can be tricky because the triggers go to sleep after a little while if they don't sense the magnet. You should measure ~12v across the low voltage coil and see it drop near 0 when triggered. I can't remember if it stays 0 while the magnet stays near the trigger or it returns to 12v after a few milliseconds. It's certainly too brief to measure with a multimeter on a running engine and possibly also impossible when turning by hand. I've measured it before with an oscilloscope.

[Squeaky]

Thanks, Chris. I don’t remember for sure what led me to change trigger magnet but I did confirm that it was 180 deg off. I have the three wire triggers with yellow, red and black. It must function somewhat to run somewhat but roughly. We tried two different timing lights with no spark flash at all from either coil.

Coils are marked as being 3 ohm on primary but meter measured 1.9 ohm on both of them. Any additional insights?