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RV-12 G3X engine data goes RED at idle RPM

WA85

Well Known Member
Not trying to one up Paul Dye with his "Weird Rotax Problem" thread, but I have a "whacky Rotax problem...."

I am providing flight instruction to a new owner of an RV-12 with a Garmin G3X.

During last night's flight, almost every time we reduced power to idle, with a corresponding reduction in engine RPM, the engine oil pressure, temp, and EGT would jump up into the red zone, add power and increase RPM, all the indications would return the normal green zone.

It takes about 3-5 seconds for the indication to trend into the red zone for all three (oil temp, pressure and EGT) and about 2-3 seconds for it drop into the green zone again.

It was clear to us that this was an indication problem, because it only happens when the engine is at idle RPM in flight or on the ground. During normal cruise and take off, all indications are normal.

Is this possible related to alternator issue? Poor ground(s)?
 
Sir,
Where is the Rv-12 Based? I’ll be out at Moontown on Sunday. Would like to see the plane if it there.
 
All those red zone limits are set in G3X Configuration Mode, and are easy to reset. Next time the parameter to red, get the numerical readings and see if those parameters deserve to be indicated as red, yellow, green, or nothing.

If you decide that the red zone limits are inappropriate -- and best check with Van's or Rotax first -- and if you need to fly to Savannah, I'll reset them for you in exchange for a ride in the -12. Or, I can send you a copy of the appropriate section of the G3X Touch installation manual and you can do it yourself, but I need an email address for you.

If the engine is healthy, all this is a non-event, basically.

Ed
 
Configuration File

Not trying to one up Paul Dye with his "Weird Rotax Problem" thread, but I have a "whacky Rotax problem...."

I am providing flight instruction to a new owner of an RV-12 with a Garmin G3X.

During last night's flight, almost every time we reduced power to idle, with a corresponding reduction in engine RPM, the engine oil pressure, temp, and EGT would jump up into the red zone, add power and increase RPM, all the indications would return the normal green zone.

It takes about 3-5 seconds for the indication to trend into the red zone for all three (oil temp, pressure and EGT) and about 2-3 seconds for it drop into the green zone again.

It was clear to us that this was an indication problem, because it only happens when the engine is at idle RPM in flight or on the ground. During normal cruise and take off, all indications are normal.

Is this possible related to alternator issue? Poor ground(s)?

There is a configuration file that is custom built for Vans for this aircraft, it does specify several EIS gauge parameters, including Oil pressure. Do you know if this aircraft has the most up to date configuration file loaded into the system?

Thanks,

Justin
 
Rotax uses sensors that are grounded to the engine case, instead of the better type of sensors with a separate ground connection. Look for grounding issues.
 
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