On my side, the pressure drops are way steeper and more worrysome, and we have checked the actual pressures as registered in our UMA sender and they check.
The airplane is a Bristell barely 25 hours old. We originally had a Rotax fuel pressure sensor that was indicating ridiculously high pressures on my Challenger MGL iEFIS, but got a UMA one (100 psi) that is compatible with my EFIS (I have no dedicated engine monitor), and they stabilized somewhat in normal ranges. We don't have analogical pressure gauge, but have checked that after the pumps the pressure is the one that is showing in the iEFIS.
I got 23-26 HG" readings from the manifold pressure in the MGL in an ill-advised test flight up to 7000 feet where the fuel pressure dropped to the 0.7-1.0 ranges, when I decided that discretion was the better part of valor and descended immediately.
BTW, we exchanged the mechanical fuel pressure regulator with one cannibalized from another engine that our Rotax dealer had, and no dice. Same results.
If anyone have any idea to diagnose this problem, I will be very grateful.
