My question is: does this sound like normal operation......
I recently installed the EngineBridge wifi module to see what my ignition is doing. I'm able to see 1/sec what the timing is advanced to for both PMAGs together on my phone screen via wifi.
IO390, dual PMAG, operating 2400 RPM with about 24 MAP. Steady cruise for quite a while.
I see the setting vary up and down 1.4 degrees (1.4 is the step size I know) and not just sit on one setting. It is 24.... then 25.... then 24..... etc. It will be the right side mainly; then I raise MAP a hair, then the right stabilizes and the left changes. Sometimes they both come and go a bit.
My instruments aren't showing me altitude, MAP or RPM changes when this is going on. So I wonder why the PMAG is so sensitive that it wants to change the timing so often. Of course this is assuming the EngineBridge is accurate.
Also, my system is timed at TDC, with 20BTDC being the timing mark of the IO390. I have the PMAG set for -7 setpoint and 29.4 max advance. The PMAG system starts at +4 on a -25 assumption for a TDC making it fire at 21 BTDC or +1 from what an IO390 wants. So when I see 25 degrees of advance in flight I assume it is really +7 ATDC -25 (assumed by PMAG) - 25 (the reported advance) =43 BTDC which would be 23 degrees of advance for my ignition at that point.
But why does the timing setpoint wobble around so much?
I recently installed the EngineBridge wifi module to see what my ignition is doing. I'm able to see 1/sec what the timing is advanced to for both PMAGs together on my phone screen via wifi.
IO390, dual PMAG, operating 2400 RPM with about 24 MAP. Steady cruise for quite a while.
I see the setting vary up and down 1.4 degrees (1.4 is the step size I know) and not just sit on one setting. It is 24.... then 25.... then 24..... etc. It will be the right side mainly; then I raise MAP a hair, then the right stabilizes and the left changes. Sometimes they both come and go a bit.
My instruments aren't showing me altitude, MAP or RPM changes when this is going on. So I wonder why the PMAG is so sensitive that it wants to change the timing so often. Of course this is assuming the EngineBridge is accurate.
Also, my system is timed at TDC, with 20BTDC being the timing mark of the IO390. I have the PMAG set for -7 setpoint and 29.4 max advance. The PMAG system starts at +4 on a -25 assumption for a TDC making it fire at 21 BTDC or +1 from what an IO390 wants. So when I see 25 degrees of advance in flight I assume it is really +7 ATDC -25 (assumed by PMAG) - 25 (the reported advance) =43 BTDC which would be 23 degrees of advance for my ignition at that point.
But why does the timing setpoint wobble around so much?