This is the final chapter...I hope. In retrospect going at my in-flight shutdown problem in a piecemeal way cost time and money. (as an aside this makes Henning right)
Sequence followed was this:
1. On the ground in Virginia replaced the contacts with new. Checked out ok on ground but I had to land after only 50 miles because one plug (on #4) wasn't firing. Mechanic took off mag cap, didn't find anything, replaced cap, and I flew the final 2 1/2 hours home without further incident.
2. Based on comment from guy working TCM booth at AOPA Expo (TCM is now producing the Bendix mags) my mechanic replaced the 2 capacitors (over 200 bucks!) which reside inside the mag cap. On a capacitance tester the old capacitors checked out just fine. Hmm. Did runups without cowl and everything was Ok. Put cowls on, mechanic and I jump in plane, taxi out to hold short line, do run up and the top plug on #4 isn't firing. Taxi back to hanger. Ack.
3. All mechanics working on this issue had commented (negatively) about the ignition harness. So I order a new one. Put it on Thursday. Did some runups and noticed something very strange to me. While doing a lean runup when I was on the left mag only, the EGTs on 2 of the cylinders did not rise. That meant (I think) that with the right mag grounded out two of the plugs which it fires (#2 and #4) were still firing. Very, very strange. (This is something that absolutely would not be caught with a normal runup (and without an engine analyzer), which I also did and got a very normal 40 to 50 dF drop on both sides.) So I bit the bullet and called Aircraft Spruce who did have a rebuilt mag in stock.
4. A friend flew me down to KFFC this morning; Aircraft Spruce van picked us up; I bought the new mag and flew back to 9A1. Put new mag in (btw new mag comes with new capacitors...sigh), triple checked point gaps and timing. Did runups and all indications were as they should be. Put cowls back on, taxied to hold short line, did runup, and everything's still OK. Took off, climbed to 4500' (1000 fpm at 90 kts IAS. Hmm, this is good.) Leaned back to about 50 dF LOP and did mag check. Perfect. Flew around a little at 4500', 2500rpm, 40 dF LOP, 148 kts TAS, 9.5 gph (hmm, this is good too.) Landed. Put plane away.
5. Wrote up saga for friends on PoA.
Sequence followed was this:
1. On the ground in Virginia replaced the contacts with new. Checked out ok on ground but I had to land after only 50 miles because one plug (on #4) wasn't firing. Mechanic took off mag cap, didn't find anything, replaced cap, and I flew the final 2 1/2 hours home without further incident.
2. Based on comment from guy working TCM booth at AOPA Expo (TCM is now producing the Bendix mags) my mechanic replaced the 2 capacitors (over 200 bucks!) which reside inside the mag cap. On a capacitance tester the old capacitors checked out just fine. Hmm. Did runups without cowl and everything was Ok. Put cowls on, mechanic and I jump in plane, taxi out to hold short line, do run up and the top plug on #4 isn't firing. Taxi back to hanger. Ack.
3. All mechanics working on this issue had commented (negatively) about the ignition harness. So I order a new one. Put it on Thursday. Did some runups and noticed something very strange to me. While doing a lean runup when I was on the left mag only, the EGTs on 2 of the cylinders did not rise. That meant (I think) that with the right mag grounded out two of the plugs which it fires (#2 and #4) were still firing. Very, very strange.
(This is something that absolutely would not be caught with a normal runup (and without an engine analyzer), which I also did and got a very normal 40 to 50 dF drop on both sides.) So I bit the bullet and called Aircraft Spruce who did have a rebuilt mag in stock.4. A friend flew me down to KFFC this morning; Aircraft Spruce van picked us up; I bought the new mag and flew back to 9A1. Put new mag in (btw new mag comes with new capacitors...sigh), triple checked point gaps and timing. Did runups and all indications were as they should be. Put cowls back on, taxied to hold short line, did runup, and everything's still OK. Took off, climbed to 4500' (1000 fpm at 90 kts IAS. Hmm, this is good.) Leaned back to about 50 dF LOP and did mag check. Perfect. Flew around a little at 4500', 2500rpm, 40 dF LOP, 148 kts TAS, 9.5 gph (hmm, this is good too.) Landed. Put plane away.
5. Wrote up saga for friends on PoA.
