Electronics International CGR-30 Combo install with fuel senders and SureFly ignition

[carusoam]

@bob865 response came in above...

-a-

[bob865]

5 minutes ago, oregon87 said:

What isolator (resistor) values are currently installed between the slick mag and EDC and between the SureFly and EDC?  We're the RPM inputs to the EDC ever connected without isolators? If so, the EDC's RPM inputs may be blown and the EDC will need to be returned for repair.

 I always recommend starting with a single 79k isolator (provided in the package) for Slick and Bendix mags and observe how the  RPM indication behaves.  If the indication is jumpy and high, there isn't enough isolation and an additional resistor should be added (79k or 47k).  If the indication is jumpy and low and may not read until higher power settings, there is likely too much isolation and that value should be reduced.  The SureFly system is a bit more difficult as what SureFly recommends to use with our systems, doesn't always work.  We have contacted their engineers to ascertain exactly what signal their system outputs and from what we can determine a 24.1k isolator should work with our systems which utilize and EDC-33.  Worth noting, that value of isolator will not be enough with our standard R-1 tachometers which are configured for standard magnetos.  

We started with the 79k and after advice from support we switched to the 47k.  Still no indication from either mag at 47k.   It was never run without isolators.  I was the guy with the key on the first start and watched the mechanic remove the 79k when asked to switch to 47k so I know it was never run without the isolators.  I spoke with Surefly also and they suggested 8-18k for their mag.  I spoke with EI support and they suggested trying 23k and said 8k-18k would probably work too with the surefly.  They were at a loss why the slick wasn't working at 47k.  They said their mag puts out a 60V pulse with a 10v offset, 2 pulses per revolution for four cylinder engines, in case that helps you guys in the future.  Support did recommend we try the 23k with the slick also to try to get a response, but to not go any lower to prevent any damage.  I am going to give the other resistors a try tomorrow morning.  I was able to locate a spread of values in my old electronics stash, but I have a suspicion I'm going to be packing it up and sending it in this weekend.

[MichMooney201]

On 8/13/2020 at 7:08 PM, bob865 said:

Hey @MichMooney201.  I just installed my CGR finally and fired it up today, but had no RPM.  EI is telling me to keep trying smaller resistors to get it to work.  Did you have any issues with yours?  Do you know what value you ended up having to use to get it to work?

Yes, as a matter of fact we still dont see RPM on the electronic ignition, but get it on the mag during run up.  We just went down for annual today and we are installing the correct resistor to get the rpm to read on the electronic ignition.  I will report back as to what that size is.  Just as an FYI, we checked with both EI and Surefly about getting it to work and both places said just keep trying resistors.  Option B is to put a dial on it like the panel lights and turn it until you get the RPM to show.  When it shows, dont move the knob and put a meter on the dial and read the resistance and you will have a real good place to start with the correct resistor.

[oregon87]

What we have found is that SureFly's tach output signal does not appear to be consistent.  What isolator value works for one system, does not work on another.  Having discussed this further with SureFly's engineers, we calculated that a 4.02K isolator should work to interface their system with our CGR/MVP systems.  Of course, after we made that determination, we have had reports from customers that 4.02K is still too high a value.  SureFly has developed an interface box, however, the first one we have had experience with results in RPM displaying half of what it should.  We believe it is because SureFly only triggers 1.5 times per cycle instead of the industry standard of three times per cycle for a six cylinder application.  However, it appears they did use the industry standard to triggering twice per cycle in 4-cylinder applications.  

Edited October 1, 2020 by oregon87

[kmyfm20s]

On 8/14/2020 at 3:06 PM, oregon87 said:

 The SureFly system is a bit more difficult as what SureFly recommends to use with our systems, doesn't always work.  We have contacted their engineers to ascertain exactly what signal their system outputs and from what we can determine a 24.1k isolator should work with our systems which utilize and EDC-33.  Worth noting, that value of isolator will not be enough with our standard R-1 tachometers which are configured for standard magnetos.  

After a week of trial and error I settle in 19.6K resistor. Between my SureFly and EI MVP-50. It seems like 17K-20K worked well and is where I would recommend people start. I wasted a lot of time playing around from 0-12K.

[MichMooney201]

All,  our A&P got the resistor installed for the Surefly ignition and a 3000K unit was what we needed to get the RPM to show correctly, and it is now reading the same across the mag and Surefly during mag checks on run up.  Will continue to update everyone as things change, if and when they do.  Thanks!

[carusoam]

Great follow up MichM!
 

Thanks for sharing the detail...

Best regards,

-a-

[bob865]

I was finally able to get mine to work as well with an 8k resistor. 

[kmyfm20s]

Funny the variation in resistor sizes.