Erratic RPM on Rotax 912ULS

[eswalllie]

This has been operational for years and all of a sudden I get erratic rpm anytime above 4500 rpm. I was told by Dynon to install a 60k ohm resistor. I think that this resistor is supposed to be in series (inline) to Pin 32. Is this the correct way to install it? Also, is there only one resistor required?
This is driving me buggy!
Any help would be appreciated.

 

[eswalllie]

After butchering the wiring with the resistor fiasco, a replacement unit fixed the problem. Thanks, Dynon!

 

[HFMan]

Which unit did you replace?

 

[eswalllie]

EMS-220

 

[Steveden]

This has been operational for years and all of a sudden I get erratic rpm anytime above 4500 rpm. I was told by Dynon to install a 60k ohm resistor. I think that this resistor is supposed to be in series (inline) to Pin 32. Is this the correct way to install it? Also, is there only one resistor required?
This is driving me buggy!
Any help would be appreciated.

a single resistor, in series.
Trigger Coil (Rotax 912, except 912 iS)
The Rotax 912 engines have a 5th trigger coil for the purposes of electrically monitoring rev counts. This trigger coil outputs to a two-wire harness. Connect either of the two wires to ground; connect the other white wire to SV-EMS-220 Pin 32 (Standard RPM Left Input). If you observe erratic tachometer readings or momentary “spikes” in the display - particularly at higher RPM – install a 60K resistor inline (in series) between the trigger coil and SV-EMS-220 Pin 32, White/Green wire). Set Pulses / Revolution (PPR) to 1: SETUP MENU > HARDWARE CALIBRATION > EMS CALIBRATION > TACHOMETER CALIBRATION > PUL/REV (C37 P32/34)