[JohnF]

I am reluctently posting this because it might help someone. I say relunctant
because it always seems soneone wants to contradict or nit pick you. But here goes anyway:

If you suspect a bad oil pressure sender and can't be certain if it is the sender or the Dynon D180, do this: Disconnect the wires from the sender and connect a resistor with one end grounded, and the other end to the wire that goes to pin #6 of the 37-pin plug into the Dynon. Here are some values you might use; a 22-ohm resistor produces a reading of 12-psi on the Dynon, a 50-ohm gives 25-psi, a 100-ohm gives 66-psi, and 150-ohm gives 100-psi (which I suspect is the highest the D180 would read in any case.)

I hope you never need this information, but I see another rv-12 flyer just posted an oil pressure failure.

FWIW

 

[Mich48041]

need more information

JohnF,
Thanks for posting that information. It will help others. I am not nit picking, but I need more information to understand exactly how to perform the test using resistors.
1. Do you disconnect the WHT/YEL wire from pin 6 of the Dynon EMS and connect the test resistor to this same pin 6?
2. Or do you connect the test resistor to the WHT/YEL wire on the engine side of the firewall? If so, what about the RED 12 volt wire that goes to the OP sending unit? Do you use that RED wire for the resistor test?
I am curious about the size of the threads on the OP sender. Any chance of you measuring them? Websites list the thread size at 1/8" x 27. It seems strange that the OP sender would have English threads when all of the other Rotax fasteners are Metric.
Thanks,
Joe

 

[JohnF]

OP Sender

The OP "hole" in the 912 is 1/8 x 27 NPT.

The easiest way to check if the D180 is at fault or if the OP sender is at fault is to disconnect both wires from the OP sender, then simply 'snip' the wire that goes into pin #6 of the 37-pin connector on the back of the D180. You might be able to insert another small wire into the "hole" where the #6 wire is connnected so you wouldn't have to snip anything.

You then connect a resistor to ground and to the wire that is still hooked to pin #6. (or to the small one you managed to insert as mentioned above) ..any value resistor from 10 ohms or so up to 100 will give you a reading on the D180 if the D180 is working properly.

I noticed that the value of the resistor and the resulting op indication on the D180 is almost a linear relationship, that is, doubling the resistance value about doubles the reading. I only had a few resistors at the hangar so I couldn't try a many , and I suspect the max reading the D180 will give is 100 psi, but I didn't check that.

 

[mrt890]

Testing OP on Dynon

I got this test from Dynon for the OP.

Take a 3V battery and hook neg to Aircraft ground and positive to the White/Yellow(break the connection) wire in the engine compartment going into the panel.

IIRC the D180 should read about 70psi. This will prove the D180 and resistor in the switch module are working correctly. I recommend you call Dynon for the specifics on this before doing it.