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Wiring a Dual EFII system using Aeroelectric Z-13

carrollcw

Well Known Member
Hey all,

I am preparing to wire my RV7 iaw the Z13 diagram in Aeroelectric. My question is, what busses and switches are you using for the system?

The dual ignition should be wired to 2 single pole ignition switches. Are you putting them both on the main battery bus, the e-bus, or splitting them between the 2 busses?

There are 2 ECU's. My understanding is there is no need to have them switch activated, but are you all switch activating them anyway? What bus are you putting them on? I am thinking that if I put them on the main battery bus, they should be switch activated. However, if I put them on the e-bus, they don't need to be...

There are 2 fuel pumps: a primary pump and a secondary pump. Only 1 should be running at a time. I am thinking of also putting them on the main battery bus with a single dual pole switch (on-off-on). Any other recommendations?

Thanks!
 
I have the dual ECU EFII ignition, I wanted the ability to isolate each ignition so I could verify each ignition was working properly during my runup. If one ignition went haywire in the air I want to be able to shut it off. I wired 1 to my main bus and 1 to my EBUS trying to eliminate a single failure point.
Good luck!
 
I just used Roberts wiring harness and wired it according to the schematics. I'm also using his bus manager which makes everything very simple and automated. I do gave a fuel pump selector switch but the bus manager automaticity switchers to the backup pump if low fuel pressure is recognized. I also have the duel ECU setup and my wiring harness came with a toggle switch which allows me to switch to each ECU manually if I want to check each one independently. Don't you guys have the same setup as I do?? Or should I have wired mine up differently for a wider safety margin?
 
I have the complete EFII setup with Dual ECUs on my Lyc IO-360. I am wiring one ign, one ecu, and one fuel pump to the Main bus, and the other set to the HOT battery buss adjacent to the battery. I will then run the wires through the appropriate circuit breaker, through a Lever Lock Switch, and into the system.

Here is a pic of my diagram and how I intend to use it.

Z-13%3A8%2BComplete%2BModified%2Bfor%2BN164AK.tif
 
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Wiring

I wired my dual ECU's so I could select either the main buss or an aux. battery. I used two single pole-double throw, three position toggle switches. The up position selects the main buss, the center position is "off" and the down position selects the aux battery.

The aux battery will power both CPU's for several hours, at least long enough to get to an airport in case the main buss fails.

The aux battery is charged from the alternator through a big Shottky diode that allows the current to flow in only one direction and prevents the aux battery from trying to power the failed main buss.

Robert OK'd my schematic before I installed the system.

I'm sure that you're going to love your EFII system! I know I do!
 
I ended up wiring them both to the hot battery bus that is backed up by a standby alternator. They are wired via a single pole switch so I can shut them down and not drain the battery. I like the dual pole idea though.
 
My system

I have wired mine so that one side is powered thought the VPX, and the other directly from the battery through a fuse. Not flying yet, so don't know if that is the best way, but seems to offer some measure of redundancy.
 
Would it be possible to run the EFII through a VPX Pro and use the VPX page to isolate the ECU's as part of the run up checklist? I'm trying to avoid extra switches on the panel but still want control to ensure both are working.
 
Would it be possible to run the EFII through a VPX Pro and use the VPX page to isolate the ECU's as part of the run up checklist? I'm trying to avoid extra switches on the panel but still want control to ensure both are working.

I would caution against running the current through the VPX or any other device. In my opinion, the KISS factor applies here. This is a critical system that absolutely must work for your engine to keep turning, and for you to remain in the air. This is why I wired one of ECUs to the HOT Battery Buss. If I have battery power, and the simple thermal CB isn't tripped, the engine will be turning. If you run both of your ECUs through the VPX and there is a fault or failure in the VPX hardware, the connectors, the software, or the wiring, you WILL be landing weather you are ready or not.

With the Dual ECU system you should have 7 switches.

1. ECU 88 Power
2. ECU 77 Power
3. IGN Coil 1 (Left) Power
4. IGN Coil 2 (Right) Power
5. Primary Fuel Pump Power
6. Secondary Fuel Pump Power
7. ECU Select Switch

You can eliminate one of the ECU power switches by using a SPDT switch. I would suggest a MilSpec Lever Locking switch. This will prohibit you from inadvertently switching off the power. With a lever locking switch, you must pull the switch out, then move it to actuate it. It will not simply move to the off or on position by bumping it. Keep in mind the single point of failure issue with one power switch. Milspec switches aren't likely to fail, but it can happen.

The ECU selector switch can be flipped as apart of the run-up checklist to test both ECUs. This switch is included with, and shipped with the system. With the dual ECU option, ECU 71 controls one ign coil, ECU 88 will control the other ign coil, and the ECU that you have selected will control the fuel injectors. ECU 88 is considered primary, however both ECUs will function the same.

You should start the engine on ECU 88, switch to ECU 71 on run-up, then back to ECU 88 for flight. You should also independently shut off one of the IGN coils at a time, turning them both back on before flight.

During the run-up, if you want to test the full functionality of both systems, I would suggest using the following procedure.

EFII Switch Positions for Engine Start: (prior to run-up)
ECU 71 and ECU 88 Power - ON (Can be combined into one SPDT switch)
Left and Right Ign Coils - ON
Primary Fuel Pump - ON
ECU Select Switch - 88

EFII Run-Up
Engine - 1700 RPM
Left Coil - OFF (check for small RPM drop)
Left Coil - ON
Right Coil - OFF (check for small RPM drop)
Right Coil - ON
ECU Select Switch - 71 (check that engine continues to run)
ECU Select Switch - 88
Secondary Fuel Pump - ON (watch for fuel pressure to raise slightly)
Primary Fuel Pump - OFF (watch for fuel pressure to drop slightly but remain satisfactory, and engine continues to run)
Primary Fuel Pump - ON
Secondary Fuel Pump - OFF

Hope this helps.
 
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I am in the camp that at least one, (i have both systems) should be wired straight to the battery. I do not want any failure other than the unit to cut off power to the ignition box. i have both units come off the hot side of the master, each with its own wire, through a fuse to the switch then to the box.

bob burns
RV-4 N82RB
 
What is the purpose of the ECU power switches? You already have the select switch for your preflight checks, is there ever a routine need to kill ECU power?

My thinking is to have them on the battery bus. Killing the coil and fuel pump power should prevent any unwanted swinging of the prop.
 
What is the purpose of the ECU power switches? You already have the select switch for your preflight checks, is there ever a routine need to kill ECU power?

My thinking is to have them on the battery bus. Killing the coil and fuel pump power should prevent any unwanted swinging of the prop.

I'd imagine that even if your ECUs are wired to an always-hot battery bus, you want to be able to shut them off when you power down the airplane so they don't sit there draining the battery...
 
I meant that they would be wired after the master relays. So you turn on/off battery power and that controls them.
 
I meant that they would be wired after the master relays. So you turn on/off battery power and that controls them.

You don't want to wire your ECUs to the master relay, because that's a single point failure that would kill both of them.

You want at least one ECU, pump, and coil wired directly to an always-hot battery bus or an endurance/emergency bus (I'd wire all ECUs, pumps, coils). That way you're minimizing the potential electrical failures that could cause the engine to stop, and if you really needed to (e.g. you lose your alternator(s) ) you can kill the master switch and everything goes off but the things needed to keep the engine going.
 
My install of the EFII system

I have read the posts and there are many iterations of the EFII installations. Below are the details to my installation. I also included a link to my panel that Steinair is cutting out for me. The two lights above the primary EFIS will be deleted. I will have these EFII signals go directly into the Dynon for a visual and audible warning.

PBRV7G3X.9.PDF


? I have the ECUs wired directly to the essential bus through a circuit breaker with no switch. When the main key switch is on, the ECUs are powered.
? I have the fuel pumps wired directly to the essential bus through a a pair of circuit breakers with no switch. When the main key switch is on, the fuel pumps will be powered. If I wish to have the busses energized for an extended period I will pull the fuel pump breakers.
? My startup will be as follows:
o Power on the Dynon with its internal backup battery
o Check switches:
 Mixture Knob neutral
 Emergency Power Off
 ECU selector 1
 Fuel pump switch 1/Auto
 Battery Selector (Make selection 1,2,both)
 Ignition 1 On
 Ignition 2 On
o Turn the key switch to on.
 The Bus Manager should detect low fuel pressure and automatically switch to secondary fuel pump.
 Verify ?Backup fuel pump running? warning on Dynon panel
 Cycle fuel pump selector switch to 2 and back to 1/Auto
 Verify ?Backup fuel pump running? warning on Dynon panel goes away.
o Clear Prop
o Press start engine switch
o Verify oil pressure
o Turn on Primary Alternator
o Turn on Backup Alternator
o Run up engine to 1700 RPM
 Cycle ECU switch to 2 and back to 1. No engine change.
 Cycle Ignition 1 switch Off and then On. No more than 50 RPM drop.
 Cycle Ignition 2 switch Off and then On. No more than 50 RPM drop.
o Cycle propeller
 
You don't want to wire your ECUs to the master relay, because that's a single point failure that would kill both of them.

My apologies, I confused Z-13 and Z-14. The system I'm designing is very close to Z-14. When you have two independent electrical systems, I think its reasonable to wire the ECUs to each bus without a switch. Having two less switches is nice because all the switches required for this system already take up a decent amount of space, and in an emergency less controls to deal with make better chances I'll do the correct thing.

On mine there will still be a pullable breaker for the ECUs.

Any reason why this would not be a good idea on a Z-14 system?
 
I'm installing the EFII six cylinder ignition version and the wiring is as follow:

- Bus Manager's Essential, redundant with the included emergency power switch switch, plus an additional external bypass made of a 40A relay with 2 Schottky diodes wired on the 2 batteries.

Since this is a 6 cylinder engine, EI works with 3 coils and if you turn off the third Coil, you'll lose the cylinders 5 & 6. The only way to proceed to "mag selection" is to shut off one ECU at a time (they have a quick run up boot program).

- ECU 71: 5A breaker plus ON/OFF SPST switch for "mag 1" selection.

- ECU 88: 5A breaker plus ON/OFF SPST switch for "mag 2" selection.

Note: I've found 2 leds illuminated SPST switches: red when OFF, green when ON. Fancy! They are protected by 3 switch guards.

- 3 COILS: manual says all in one with a 15 A breaker. This is to me a single point of failure so I've added a protected SPDT switch going to a second 15A breaker in case the first fails.

- BTW, Bus Manager's Main is going to the VP-X Pro, with the same kind of double Schottky redundancy.

May be too cautious, but I think an "electric airplane" needs extra-care to be safe.

Hope this helps.
 
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Definitely can't hurt to add extra protection where you can... however, you should note that even though there are three coil packs, each coil is its own individual unit. Unless you looose the whole plug to a coil, you would never looose a whole coil.
When I shut down one ECU during my run up test, I have 1.5 coils running either the top or bottom plugs.
 
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You are right John.

Mine is a 6 cylinder and the purpose of my message is I definitely can't shut off the third Coil at all. This would make me lose the entire last 2 cylinders (the third Coil, even though it's a dual coil, is powering the top and the bottom of these cyl. 5 & 6).

That's why the "mag selection" is done, in that 6 cyl. case, shutting off the ECUs.

Happy building!
 
Fuse Protection Level ?

It is my understanding of input from Ross ( SDS) that coils and CPU's shall be fuse protected independently. Therefore, it is my expectation that any type of coil or CPU failure, whether open or short, would be benign with respect to "upstream" busses and devices. So I plan to assure there are two paths of battery power to THE buss from which the EPI's get power. Any comments from this obviously knowledgeable group ?
 
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Please be aware that SDS and EFII architectures are quite different, especially on the dual ECU 6 cylinder systems. I don't want people to be confused here.
 
I find it interesting that no one has yet mentioned the power lead for the injectors (though perhaps I missed it). I just installed an Aerosport IO-375 engine on my airplane which came with the EFII dual ECU system. As I understand (and I could be mistaken) there is a single wire (red) which powers all of the injectors, and the ground leads from the injectors go to the ECU's which control their operation. The EFII system does not have independently controlled injectors, which is why you can use any of the leads for any of the injectors. (as an aside, I think this can be rewired by changing the ground leads from the injectors to the "Injector drive plug" on each of the ECUs and wire them to specific terminals on those plugs so that they can be tweaked individually--alla Dave Anders setup). That injector power lead was bundled with the ignition coil leads, which could be wired to switch buses through a switch (which then that switch becomes the single point of failure, along with the wire to the injectors--I believe that if you lose power to that injector power wire, your engine stops). I choose to separate the ignition coil power leads and wire them to their respective ECU power sources (also each pump is run from the separate power sources). Then I used a SPDT switch to select the power source for the injectors. As recommended in other posts, I have a separate battery and power bus as a backup, which is totally independent (other than a power diode for charging the battery) from the main bus battery and alternator.

I don't know if it is right or wrong, but I believe it gives me a little more redundancy and backup alternatives. Though the switch and power lead to the injectors is still a single point of potential failure--there is no getting around that practically.
 
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The individual cylinder trim function is a software enabled feature. Its my understanding that despite the fact that the EFII product is based on the SDS CPU, Robert does not offer that (and a variety of other functions) for the EFII product. Somebody feel free to set me straight if this is inacurate.
 
SPDT >> DPDT

Dave M - I wondered what to do with the single injector lead too. My plan was similar to yours except to wire through a DPDT switch instead of a SPDT. Wired in parallel thru the switch to have two sets of contacts in the mechanism controlling the current. Not sure what the switch failure modes really are mechanically for the DPDT switch so I don't know if this really increases reliability/redundancy of the switch path. Of course you would never know if both legs were always working unless you occasionally inspected the switch. Two independent SPST was the other option but I don't want another switch....
 
I have read the posts and there are many iterations of the EFII installations. Below are the details to my installation. I also included a link to my panel that Steinair is cutting out for me. The two lights above the primary EFIS will be deleted. I will have these EFII signals go directly into the Dynon for a visual and audible warning.

PBRV7G3X.9.PDF


? I have the ECUs wired directly to the essential bus through a circuit breaker with no switch. When the main key switch is on, the ECUs are powered.
? I have the fuel pumps wired directly to the essential bus through a a pair of circuit breakers with no switch. When the main key switch is on, the fuel pumps will be powered. If I wish to have the busses energized for an extended period I will pull the fuel pump breakers.
? My startup will be as follows:
o Power on the Dynon with its internal backup battery
o Check switches:
 Mixture Knob neutral
 Emergency Power Off
 ECU selector 1
 Fuel pump switch 1/Auto
 Battery Selector (Make selection 1,2,both)
 Ignition 1 On
 Ignition 2 On
o Turn the key switch to on.
 The Bus Manager should detect low fuel pressure and automatically switch to secondary fuel pump.
 Verify ?Backup fuel pump running? warning on Dynon panel
 Cycle fuel pump selector switch to 2 and back to 1/Auto
 Verify ?Backup fuel pump running? warning on Dynon panel goes away.
o Clear Prop
o Press start engine switch
o Verify oil pressure
o Turn on Primary Alternator
o Turn on Backup Alternator
o Run up engine to 1700 RPM
 Cycle ECU switch to 2 and back to 1. No engine change.
 Cycle Ignition 1 switch Off and then On. No more than 50 RPM drop.
 Cycle Ignition 2 switch Off and then On. No more than 50 RPM drop.
o Cycle propeller

Hello my friend, could you please send me that again, the link doesn?t work any more... I?m installing dual FlyEFII system in my RV-7, with dual alt, single battery.
 
Shouldn't all electric fuel pumps be switched?

Fuel leak or fire- you could just shut off the fuel selector valve and "pull" any fuel pump circuit breakers.

Standardization comes into play for any possible future sale.

What if you are IMC or night at 10,000'? You don't want to have to shut off an essential bus.
 
VP-X flight safety note from SDS

Some in this thread have said they are/will use VP-X.

Keep in mind EFII got ECUs from SDS prior to EFII's System 32. I suppose the following would apply to any ECU however and instantaneous injector current would depend on injector coil resistance and whether injectors are fired simultaneously or sequentially.

This from the SDS EM-5 Aviation Installation Manual:

"Warning Regarding Vertical Power VP-X and SDS

It has come to our attention that the VP-X electronic switching/ circuit breaker box does not use average current draw over several seconds to trip breakers like conventional thermal breakers do. It may trip during normal operation due to peak current transients over only a few milliseconds. This can lead the pulsing current of the ignition coils and injectors to trigger the breaker far below nominal current levels. We believe this could cause a serious flight safety issue and engine stoppage. Be sure to set the breaker values on the VP-X far higher than the nominal current draw on these circuits. Be aware that average current draw can increases with rpm and load so ground running may not allow complete testing of this condition if static rpm is lower than flight rpm and engine shutdown could occur in flight. Breakers are to protect the wiring, not the device. We recommend each 4 cylinder coil pack have a rating of at least 15 amps assigned when using the VP-X, each 6 cylinder coil pack at least 20 amps, 4 cylinder injector power at 15 amps, 6 cylinder at 20 amps and 8 cylinder at 25 amps. These are only recommendations, use this information at your own risk and these values should be thoroughly tested prior to flight at WOT and maximum rpm the engine will see in flight."
 
Does anybody have the Z-13/8 figure for EFII in better quality? It cannot be seen very well...
Thanks!

*** Cautionary note... SDS EFI and EFII EFI are wired differently, especially in the case of dual ECUs ***

I put it in my google filespace linked below. It's called "Z-13-8 Complete Modified for N164AK Justin Jones Dual EFII.pdf". It's not Z-13/8 because it has been modified and Justin is using a B and C 410-H which will make 30A at cruise rpm. There are mistakes in how the ECU, coil, and injector wiring is depicted but the fundamental issue is how power is maintained.

Ross Farnham / SDS recommendation is there also "SDS wiring ECUDual4 REV 1.0.pdf". Be aware it does not show the individual injector wires going to the relays and it does not depict the fact both relays connect to both ECUs; those details are incorporated into the supplied harnesses.
 
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I caution people not to interchange SDS wiring and component layout with EFII since they are not the same, especially in the case of dual ECUs.
 
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