I'm trying to run a RAM 750 but I'm not getting CP reading on the Hand held unit ( electric start ), the glow plug is hot, the turbine is rotating, the propane is flowing, I'm getting the engine to start and run on the propane, the temp. reading is counting up but I'm not getting Case Pressure readings, with out it the pump will not start. I blew throug the lines to the ECU and I get CP readings and I blew to the engine and I can hear the air coming in to the engine so there is no restriction in the engine.

This engine run a few months ago just fine, so what the heck is going on here ( miss place the manual [&o] )

Thank you for any help that you may offer.