Hmmmm... major bummer. I think I have succumbed to the dreaded "JetJoe - your RPM sensor is knackered" syndrome. How easy are these things to swap out?

I have a brand new JJ-3000 Turbine (assumingly 'factory tested') and it just refuses to fire. All goes well on initial start-up - Starter kicks in, Propane goes *pop*...then she winds back down again. Stick and Trim are calibrated as per the instructions.

But I've noticed that the RPM on the 'Monitor' was always ZERO. Having read other threads, even if you spin the engine with a hair-dryer, you should see the RPM read at least something - but nada. I see all the other prompts on the read-out - it goes 'Ready'... 'Glowplug Test'... etc... whizzz.. *pop*....dies.

I've re-routed all my wiring, and twitched all high-current leads together, moved everything well away from the RPM sensor wires, and still nothing. No read-out whatsoever regarding RPM - I think I should be seeing it at least advance a couple of thousand RPM once the starter kicks in. But nup - jack she-ite. Maybe it's the FADEC - but then it wouldn't go through the start-up sequence, open the Propane, juice the plug and 'light off', would it? The Propane definitely ignites...I can hear it, and feel the heat afterwards. But no RPM readings anywhere along the line.

The 'Combo' I've got is running a 'genuine' JetJoe fuel pump (blue thing - 20mm diam by about 50mm tall), Regal FADEC, and JetJoe solenoids (brass fitting, yellow windings). Fuel pump/solenoid work coz I've managed to purge the kero lines no problems.

What is s a bit discrening however is that I noticed that the Propane solenoid doesn't always shut-off properly (dead 'Bad Start', close the gas valve, and when I turn the bottle valve back on, I can hear the gas injecting into the Turbine - no real worries for me, as I manually control the main gas valve anyways). I have that timing right, coz as soon as she tries to spin up, I open the the bottle valve and she lights. It worries me a little that the Propane solenoid can open (or stays open) before the FADEC calls for it. No big deal just yet, as the whole thing is on a test bench and being fired out in the open- I'd hate to think an airframe was filling with Propane before I initiate the start sequence - any aircraft with a belly full of Propane is gonna go ~POOM~ when the glowplug kicks in.

I've checked and double-checked my wiring etc. It's all 'by the book' so far...

Any ideas?

BJ