PMAG Problem

[WAM120RV]

Bill

Thanks for clarifying this, so bottom line is that this would not have happened if V40 had been installed?

In which case it still makes sense to check your leads, but the potential problem has already been sorted by EMagair, provided the mags are upgraded to V 40?

If any of you have not realised Bill is a great asset to this board!!!

[N941WR]

Originally Posted by WAM120RV

Bill

Thanks for clarifying this, so bottom line is that this would not have happened if V40 had been installed?

In which case it still makes sense to check your leads, but the potential problem has already been sorted by EMagair, provided the mags are upgraded to V 40?

Correct, or as correct as I understand the issue and the solutions we have helped others work through can be.

The real answer is that Emag (the company) has the final say on what does and does not work with their P-mags (the product), not some guy who makes a bolt on (The EICommander) for them.

Originally Posted by WAM120RV

If any of you have not realised Bill is a great asset to this board!!!

I'm not so sure about that, but thanks!

[judoka5051]

I have to agree with the poster about the choice of title for a couple of reasons. First, It will alert P-Mag owners to a potential emergency, and motivate them to get the update. Secondly, The P-Mag is supposed to be a drop in replacement for a standard mag,,, with the understanding that a loss of power is an inconvenience, not an emergency (at least in the sense that you're not going to enjoy a forced landing).

BTW, I put them in the 8A I built and loved them. So, I'm not against EI at all. In fact I'll be using the EFII in the new plane, primarily because I wanted single lever fuel injection too.

[Larco]

[quote=N941WR;1129539]I can't stress enough how important the Version 40 upgrade is!


Yes, that is what this means.

It turns out that pre-version 40, when the P-mags are powered (or spinning above 800 RPM) and they are grounded, they are in setup mode. Which means two puffs in the manifold line will change their TDC mark to wherever the crankshaft is when the P-mags get the puffs.

With the shorting described by the OP, the system was being grounded, which puts it in setup mode. (Powered but grounded is setup mode.)

When your intake valve closes there is a short duration but high velocity positive pulse in your manifold pressure line, just like the puff it takes to set the timing.

Version 40 is different in that the prop must be stationary to set the timing. Thus a spinning P-mag will not allow its timing to be changed.

So to answer the question, this problem was solved in late 2014, so depending on the vintage of your P-mags, you want to get them in for the update.-------------------



Good explanation. Thanks. Good to know why instead of just do it. Larry

[N941WR]

The next question is, "How do I know what version I have?"

The software fix came out in the fall of 2014. So, if you have had your P-mags back for a check up, they will have been upgraded to V40.

If you bought your P-mags prior to that and have not had them back since late 2014, you probably do not have V40.

1. There should be a sticker on the P-mags that list the version number, hopefully you can read it.

2. Put the P-mags in setup mode (powered AND grounded), move the prop to TDC and blow in the tube twice, observing the LED. If the P-mags let you set the timing you do NOT have Version 40. (Version 40 will not let you set the timing if the prop moves after being put in setup mode.)

3. If not, then you can connect to each P-mag with a PC via the P-mag's serial port (Pin's 2 & 3) and query them via the free EICAD program, available on the Emag website.

4. You can query them with an EICommander.

Those four options are listed in the order of expense.

[N941WR]

Added #2, above.

[rv8ch]

Thanks for the heads up on this possible failure mode.

[flightlogic]

Just a quick observation. I would not be hesitant to shut down the offending ignition source in flight. Thinking that it might be worse... just continues the rough operation. Planes fly just fine on one. Check left and right when roughness occurs. Then shut off the bad one. Simple and safe. You did go richer, which was probably a good move. Switching tanks to rule out contamination might be prudent also. Glad this thread go started... and I think most of us are fine with the title.

[gbusterguy]

We suspected an ignition problem and we were mostly concerned about turning off the good one and creating a strong backfire situation that could do more damage. Right or wrong that was the thinking. I do however understand the conventional thinking behind the mag check but it was running, not great but moving us along. We decided if it got worse we would do the mag the check. Since overheating was occurring fuel didn't seem to be the problem but I agree switch the tanks was in order. I will say that having another very experienced pilot in the cockpit to think through this compound emergency situation was extremely helpful. It's sobering to think about the flight just prior to this one, it was at night with my wife!

[6 Gun]

Sounds like the P mag company needs to pay to fix this guys engine if he was not notified of problem.
Bob