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Genival Pacheco

erratic tachometer readings in avmap engibox

by Genival Pacheco in General Tech Discussion 9 years ago

I´ve recently bought na AVMAP ENGIBOS EMS to use to monitor my 912 ULS engine and the tach Readings are not steady what can i do?

Re: erratic tachometer readings in avmap engibox

by Roger Lee » 9 years ago

Roger Lee

128 5.28k 4.98k

Tach readings can move around some and that's normal. You may set the throttle, but the reading could still move around 50 rpm or so.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

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Re: erratic tachometer readings in avmap engibox

by Rob Seaton » 9 years ago

Rob Seaton

3 1.32k 251

Roger is correct but sometimes it can be improved. The tach signal is a millivolt AC sine wave that can be overwhelmed by other RFI such as ignition, generator, strobes, or radios.
Make sure you ignition switch wires (p-leads) are shielded and the shield is not grounded at the same point as the tach wire.
See attached for some troubleshooting.

TachTroubleshooting.pdf (You do not have access to download this file.)

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Re: erratic tachometer readings in avmap engibox

by Roger Lee » 9 years ago

Roger Lee

128 5.28k 4.98k

Hi Rob,

Good point. I wasn't even thinking along those lines.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

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