EMS with Tach indications from a surefly mag

mikelupo

Member
Joined
Feb 22, 2024
Messages
45
Location
Gilford, NH
Hi. I am installing the SV-EMS-220 engine monitor. I have read several posts regarding getting tach indications from a Surefly emag. All of which seem to point to needing the Surefly tach2 board installed. As luck would have it, I do indeed have the Surefly tach 2 board installed and am picking off the 0-5V lug on the tach 2 board. I have that wired directly into pin 35 (blue wire) for the left side low-voltage input.
The result of this test is that I see 0 RPMs when I isolate to the emag.

As a sanity test, I put an ohm meter between the L plead and ground lugs on the tach 2 board. When the key is in the off position, the plead is positively grounded from the tach 2 board's perspective and my ohm meter beeps. Conversely, if I set the key position to the emag, the circuit between the ground and plead is open from the tach 2's perspective. So it seems that there are no wire gremlins (caused by me) to remedy.

Has any one had this problem and how did you rectify?

Thanks,
Mike

ps... I get tach indications from the slick (analog) mag so at least I have that.
tag @Dynon
 
Last edited:

preid

Member
Joined
Jan 22, 2010
Messages
754
Location
SoCal
“have that wired directly into pin 35 (blue wire) for the left side low-voltage input.”
Blue which is pin 34 is correct
be sure you don’t have 35 configured on gauge. ;)
 

mikelupo

Member
Joined
Feb 22, 2024
Messages
45
Location
Gilford, NH
Thanks Preid. I think I did do all that. I just got back from almost 4 weeks on the road so I'll be back in the hangar this weekend to resume. I did buy a hand-held oscilloscope off amazon, so I should be able to test the Surefly Tach2 board for output.
 
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