secondary miss on #3 cylinder

[robin]

My #3 cylinder is missing on my secondary ignition. On the ground at 2000 rpm, mags only will show about 20 rpm drop, secondary only will show 200 to 300 rpm drop, vibration starts, sounds like a missing cylinder and #3 cylinder EGT drops rapidly. Engine starts instantly.

Initially the problem was intermittent in that on some flights no issue and on others every test of the secondary produced the miss.

My remedy attempts were as follows:

My first suspect was a coil as I have had to replace both previously. I bought a new coil and swapped out each coil. No difference.

Tested each spark plug for spark. All OK.

Replaced #3 spark plug. No difference.

Bought a new trigger unit and replaced the bottom trigger feeding #3. No difference.

Replaced the entire plug wire on #3. No difference.

I’m out of ideas. Any suggestions?

Robin
Sonex.

[sonex569]

Robin I would like to know the answer as I have the same problem. Just purchased new triggers, installed and missing bad, I would like to know how to install triggers and get them 180 degrees apart. I want to think that is the problem--but-- who knows??

Regards
Dick

[robin]

Dick, the triggers have 2 small screw insert positions and can only go on one way. So if you have the screws tight in the insert positions then they will be correct.

[sonex569]

Robin, thank you did not know that and did not notice that when installing. will pull plate back off and check.

Regards

Dick

[robin]

Dick
Unless we are talking about different things, the triggers are on the back of the engine and can be replaced without taking any plates off.

[sonex569]

No were talking about the same triggers. Just easier to unbolt starter and remove the alternator cover that the triggers are bolted to rather than stand on my head to get at the bolts. Can't see back there any way.
Was down to hanger today and ran engine, #3 was cold. Pulled the plug and it was not firing. Changed plug got a little better changed spark plug wire and was a little better. Changed wire on #1 now back to normal-SO- now, not worried about triggers being not 180 degrees apart.
I swapped out wires and I had no change either. But I bought a new set of wires and made a new one. Seemed to do the trick, maybe old wire just went bad don't know but new wire worked.

Regards

Dick

[robin]

Dick,
Glad you are up and running
Robin.

[sonex569]

I hope that your Ign. problem is working it self out. The only thing (I think different or maybe not) is that I run a heavy ground wire (#6) from one of the Starter mount bolts to battery ground. I also run one from the engine block to battery ground. If the spark plug does not have a good ground it will miss fire or not fire at all.

Just a thought.

Regards

Dick