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dholly
04-21-2014, 08:26 AM
I've installed the MGL E-1 Engine Monitor System and have a few questions for a Rotax 912UL application.

Info: I re-used the existing EGT thermocouple probe, replaced the existing single CHT thermocouple probe with (2) new NTC CHT K-Type thermocouple probes from MGL, re-used the existing Westach oil temp thermistor-style thermocouple probe and replaced the existing Westach oil pressure sender with a new VDO 150 PSI/10 bar oil pressure sender p/n 360-360-905 (Note: requires 1/8-NPTF thread, VDO p/n shown includes US Thread Adapters not required for Rotax 912UL application).

Q.1) Re: RPM - I have a Rotax tach and a TinyTach (due to suspected error of Rotax tach). I'd like to enable the E-1 tach function for a 3rd opinion. Can I wire the Rotax and E-1 tachs in series by tapping off the engine RPM out supply feed (prior to the Rotax tach) to the Blue DB9 pin 5 of the lower E-1 plug connector? Is there is a specific polarity from the engine feed (didn't think so)? There are three wires into the Rotax tach (I've identified the +12v power supply in from the bus, but would need to break open the wiring bundle to trace the other two). So, if there is a wiring standard for the Rotax RPM feed wires from the engine and Rotax tach, can anyone confirm definitively that the left top pin on the instrument (looking from behind) is connected to +12v, the right top pin is connected to Ground and one of the two wires coming from the engine (which wire, or it doesn't matter which one?) and the lower center pin is connected to the other engine feed wire. Rotax install manual is not clear on this to me. I understand the E-1 tach function will need to be set to 1 pulse per revolution.

Q.2) I've set what I feel appropriate for my 1995 vintage 912UL, but would like to hear your suggestions for EGT, CHT, OT, OP and RPM span values, plus low and high alarm thresholds.

Q.3) Has anyone added a fuel pressure sender and where in-line is best? Any way to add a fuel flow transducer or fuel level sensors (for wing tank fuel remaining or header tank low fuel warning)?

Thanks!

I found Rotax Service Instruction SI-13-1996 which confirms the top right pin on tach is Ground, and lower center pin is the RPM engine feed.

Still looking to answer the other questions, thanks.