[GCCR]

OK, sorry the term "Stop Valve" is probably innaccurate. What I mean is the pressure sensor switch (off when No pressure, ON when line is pressurised). I was hoping this would give me some useable data when connected to aN ecu Av input but it doesn't seem to work like that as the Reading goes up[ to 8v instantly when pressurised (closed contacts I assume), but doesn't then drop to 0V or anything when out of water.

I've opted for a float now and baffled the container heavily, but I'm not really happy with that as a permanent solution as a blocked jet would not show up, but would be enough to blow the engine.

How much is the flow sensor you mention ? (That sounds like the best solution of all).