Use of resistor for Tach pickup

[sidsx]

Hello all,
I am in the process of installing the Aerovee engine and the the GRT EIS 4000 with the GRT Sport EX EFIS in my Onex I'm building. The question is rather I need to use a resistor if I'm getting the Tach input from one of the wires from the alternator? I would be interested in learning what others have done for their Tach inputs for the EIS.

Thanks,
Sid Essex

[WesRagle]

HI Sid,

I used the resistor and the P-lead (per instructions) of a slick mag. Can't read RPM with the mag off. Just check "Mag Drop" by ear during run-up.

Wes

[sidsx]

Thanks Wes...

[sidsx]

Should I expect to see engine RPM indication while turning the engine over with the starter on the Aerovee 2.1?

Thanks,
Sid

[DCASonex]

The current pulled by the starter is likely to briefly but significantly lower your system voltage enough to render panel instruments inoperative or inaccurate.

David A.

[sidsx]

Thanks David,
I would like to know if anyone out there with flying aircraft could tell me if they see rpm indication while motoring the engine with just the starter. I don't want to have to tear into the wiring after I have it finished so if I should see rpm indication and I'm not now would be a great time to know I've not wirer it properly. I have wired it IAW the GRT instructions but I don't see any rpm indications.

Thanks,
Sid

[GordonTurner]

Can’t really answer the question, but are you spinning with one set of plugs removed?

[sidsx]

hi Gordon,
Yes it's with the plugs removed.

Sid

[DCASonex]

The starters current draw is enough to cause my GRT Sport SX to drop out. If just testing on the ground, find another battery to run either the starter motor, or your panel instruments.

David A.

[sidsx]

I'm not having any drop out issues everything else works fine I'm just not getting any rpm indication at all.


Sid