Engine momentarily dies

[E. D. Eliot]

Not an engine guru but I'd check the ht wires and the ignition switch first. Also the associated wiring. Look for wires that may have worn due to rubbing on an adjacent surface or simply come loose. I'd consider your symptoms as a 'warning' from your electrical system that something is going wrong. Cheap stuff first. Please let us know what you find.

[yarddart]

Try marvel mystery oil

[Tim Lewis]

Originally Posted by Earl Findlay

For the last 25 hours, since I finished the condition inspection, about five times now, when cruising or descending, the engine stalls out for just a split second and then comes back alive. By the time one can react, it's back and purring.

Do you have an engine monitor that stores data? That info might be helpful in seeing what is happening during the event.

[DTARM1]

Originally Posted by yarddart

Try marvel mystery oil

74% mineral oil
25% stoddard solvent
1% lard

You sure?

[Jimzim]

From your OP it sounds like the issue began after your most recent condition inspection, and never occurred before that. If that?s the case, then if it were me, I would look closely at everything that was ?touched? during the inspection. Maybe I am just stating the obvious, but...
Hope you find the smoking gun, and please report back.
Good luck

[Ezburton]

Originally Posted by lr172

I have had a mag fail and also often drop one mag in flight for testing. Losing one ignition system creates a small drop in RPM/power and causes the EGTs to rise. Losing one ignition system WILL NOT cause an engine to stop working for even a brief second. To get the symptoms described by the OP, BOTH ignitions would have to stop working. It is possible that the PMAG is not working and a brief drop out of the LS would cause this. However, assuming the OP does mag checks before TO, this seems unlikely.

I just don't see how one ignition can keep the other from properly lighting the charge, creating a "no fire" scenario across ALL cylinders. Having one ignition too far advanced can cause rough running and misses, but it usually lights it early (rough running and/or detonation) or, if too far advanced, not at all (cyl runs fine on other ign). The charge won't ignite untill a minimum level of compression has been applied.

Larry

Yeah... I know it doesn't make sense. But if you replace everything else and the problem doesn't go away, and then replace the ignition and it goes away... that kind of says its the ignition.

I had heard about the taller components on the Lightspeed's circuit board would break and that adding RTV to them stopped that from happening (Klaus never addmitted this was ever a problem). The thought was that all cylinders would fire at the same time. I'm not sure what that would sound like or feel like.

I recall one of the canard guys telling me that I should expect a certain amount of infant mortality in these things. When Klaus' infant mortality turns into my mortality, no thanks.

[Bavafa]

I have dual PMAG and I can change the timing of both PMAGs in the air. I believe the process is that it sends timing to one PMAG and then to the second one. When I do that, the engine for just about a half a second to a second drops, it is more like you see it in the RPM that drops about 50-70 RPM.
I wonder if this is how your perceived engine drop is and if so, if something is happening with one mag dropping and coming back alive.

[N941WR]

Originally Posted by Bavafa

I have dual PMAG and I can change the timing of both PMAGs in the air. I believe the process is that it sends timing to one PMAG and then to the second one. When I do that, the engine for just about a half a second to a second drops, it is more like you see it in the RPM that drops about 50-70 RPM.
I wonder if this is how your perceived engine drop is and if so, if something is happening with one mag dropping and coming back alive.

You are correct, your EIC sends the new configuration to one ignition, waits 30 seconds, then sends it to the second igntion. This is because the new configuration interrupts the firing for a split second. Long enough that if it changed the timing on both at the same time the exhaust would load up with unburned fuel. Then when both ignitions come back on line, it would burn off that fuel with a BANG. By staggering the configuration updates, there is never a period when unburned fuel gets dumped in the exhaust. However, we can't stop the momentary sag as each ignition goes offline to load it's individual update.

[RV7ForMe]

Originally Posted by N941WR

It is unlikely to be your ignitions.

Since you didn't mention any backfire when it comes back on line, I would suspect fuel delivery.

I would second this and look into fuel or fuel contamination...I had this once on 2 different Cessna aircraft but a year apart and it was in both times directly after getting fuel. Both times it put me in full emergency adrenaline mode but your guess is as good as mine.

[RV10inOz]

Isolate your mag switches (i.e. hot mags) and go fly.

I have resolved a problem like this before....never found the thing that shorted two mags together but isolating one mags taco wire fixed it. I assume an EMS fault or a wire strand somewhere.....

Start with basics.