Dual P-MAG Reliability in 2017

[rv6ejguy]

Originally Posted by DanH

Ross, where can I download a wiring diagram for the CPI?

For single 4 cylinder there are 2 powers (red) and 2 grounds (black) for the controller and coil pack respectively. These wires are already installed in the connectors. One more to a 12V source for the LOP switch if fitted. One wire from controller to tach. Dirt simple.

Aero CPI manual is here: http://www.sdsefi.com/cpiaircraftmanrev23.pdf

Aero supplement here: http://www.sdsefi.com/cpiaero6x.pdf

[Ironflight]

You know folks, there is a huge amount of useful (and some not so useful - you can sort that out...) data in this thread, but very little of it has to do with "PMAG Reliability in 2017". So most of the really good info will be lost because people aren't going to be able to search for it (let's all admit that the search function is pretty basic here), and they won't look under this title to find info on SDS equipment (for instance).

And there is absolutely no way a Moderator can (or will) sort this mess out.

Think about that folks - if you have presented good, new information here - think about going and starting a new thread. Or it is all lost for posterity.

[scard]

Originally Posted by Ironflight

You know folks, there is a huge amount of useful (and some not so useful - you can sort that out...) data in this thread, but very little of it has to do with "PMAG Reliability in 2017". So most of the really good info will be lost because people aren't going to be able to search for it (let's all admit that the search function is pretty basic here), and they won't look under this title to find info on SDS equipment (for instance).

And there is absolutely no way a Moderator can (or will) sort this mess out.

Think about that folks - if you have presented good, new information here - think about going and starting a new thread. Or it is all lost for posterity.

Google works just fine

"site:vansairforce.com search terms here"

Search, don't sort!

[rv7boy]

Originally Posted by Ironflight

...And there is absolutely no way a Moderator can (or will) sort this mess out...

I thought about attempting to do so...and I'm sure some other moderators thought about it, too. And then I decided, "No way!"

Thanks for saying this, Paul.

[DanH]

One debate that struck me as interesting involved the idea of "distributed components", the assertion being that wires and connectors created risk.

So, how many wires are we talking about here?

I pulled up info for SDS CPI, and P-mag plus an EI Commander, since the combination is the only way to remotely compare apples to apples in terms of operator control. (Yes, I know the relative extent of control. Let's not start that debate. This is about wire count.)





Turns out there is very little difference in how much wiring is required. Each requires two power leads, and multiple grounds. Each requires two switches. Total wire count is similar.

Directly addressing physical distribution, the only truly separate critical component is the Hall effect trigger for the CPI. It seems to be pre-wired, requiring only that the installer plug pins into the box connector after running the cable through the firewall, so install risk is minimal.

Both systems have separate coils. The P-mag merely stacks a Ford coil on top of the aluminum body, complete with external wiring.

[Toobuilder]

Originally Posted by Ironflight

...Think about that folks - if you have presented good, new information here - think about going and starting a new thread. Or it is all lost for posterity.

Fear not Paul, I have a feeling we will get to do this dance again. Fortunately there is plenty of unambiguous data in Ross’ one post to keep future debates on the straight and narrow. I’m sure several of us will be mining that one as required.

[N941WR]

Originally Posted by DanH

One debate that struck me as interesting involved the idea of "distributed components", the assertion being that wires and connectors created risk.

So, how many wires are we talking about here?

I pulled up info for SDS CPI, and P-mag plus an EI Commander, since the combination is the only way to remotely compare apples to apples in terms of operator control. (Yes, I know the relative extent of control. Let's not start that debate. This is about wire count.)





Turns out there is very little difference in how much wiring is required. Each requires two power leads, and multiple grounds. Each requires two switches. Total wire count is similar.

Directly addressing physical distribution, the only truly separate critical component is the Hall effect trigger for the CPI. It seems to be pre-wired, requiring only that the installer plug pins into the box connector after running the cable through the firewall, so install risk is minimal.

Both systems have separate coils. The P-mag merely stacks a Ford coil on top of the aluminum body, complete with external wiring.

Dan, as always, you bring in good logic; however, once the P-mags are spinning, one or more of its wires can fail and it will keep the sparks flowing. (Unless the failure is in a plug wire.)

How many wires can fail in a Distributed system before it stops producing sparks?

[krw5927]

Originally Posted by Captain Avgas

So we on VansAirforce are largely left with forming opinions on the reliability of Experimental electronic ignitions largely based on forum reports from disgruntled users.

...many of which are deleted by mods, especially when the report discusses a failure of a forum advertiser's product.

Originally Posted by Brantel

My impression is that you are more likely to see a public complaint from someone that has an issue than someone who has not.

Why would someone who has not had an issue have any cause to complain? We know what you mean though. Thing is, especially regarding a certain vendor's products, there actually are lots of threads heaping praise, whereas many (dare I say most?) threads and posts lodging complaints are actively deleted. Conversely, I don't believe I've ever seen a single "compliment" thread deleted. Expecting to search the archives and gather any meaningful data based solely on the number of threads discussing actual failures vs praise is folly.

Huge thanks to Ross for openly discussing the data! If I ever get the nerve to try another electronic ignition after my scare, it'll be one of his units.

[krw5927]

Originally Posted by N941WR

however, once the P-mags are spinning, one or more of its wires can fail and it will keep the sparks flowing. (Unless the failure is in a plug wire.)

Is this entirely true, considering the apparently critical external wire connection to engine ground?

[Toobuilder]

Originally Posted by N941WR

Dan, as always, you bring in good logic; however, once the P-mags are spinning, one or more of its wires can fail and it will keep the sparks flowing...

Do the sparks keep flowing when the coil wires (primary side) fail?

(No need to answer Bill, we know the answer)