Manifold Pressure and Fuel Pressure problem

[simon.clifton]

Hi

I ran the Rotax 912ULS engine in my SportCruiser QBK for the first time yesterday. My D120 works great, with standard sensors as provided and a Dynon loom. But the manifold pressure and fuel pressure readings are are stuck at one value - Fuel 2.06 bar, MAP 2.5 inch

Before I go back out to the hanger and check for basic wiring faults, can anybody easily tell me what I would expect to see if I have an open circuit, and if there is an easy way to independantly check the sensors just using a digital multimeter?

Thanks, Simon, UK G-MOOV
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[dynonsupport]

The MAP sensor utilized connections to the EMS's 5V output, a ground, and a signal line to a dedicated input. The output is a variable voltage between 0-5V. Pegged high pressure is 5V, which usually means that the 5V line is connected right to the MAP input. This can happen if the MAP sensor was pinned out incorrectly, which we've seen customers do on occasion. See the installation manual on our site for pictures and diagrams of the correct wiring.

 

[simon.clifton]

Hi again

I have solved the problem, my builder buddy had cross wired the manifold pressure sensor to the fuel pressure sensor and vice versa. I worked it out by fitting a potentiometer to the manifold pressure sensor wiring, and noticing the fuel pressure was changing.

The reason for the confusion was that we have had to extend the Dynon-supplied cabling, but then had to re-do it over again to route the wires away from the exhaust (and that was where the mistake happened).

Anyway, all working properly now, thanks for a nice instrument.

Simon C
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