Randy,

 

Test the existing sensor as suggested.  Also, check the connections since even a little resistance could cause a voltage drop.  On my 320, the engine driven pump supplies about 25-26 psi and the boost pump only raises that to 26-27 psi.  The pressure is measured off a tee coming out of the engine driven pump and the line to the servo and the 320 Lyc manual says the pressure should be above 12psi..  The boost pump is in series with and before the engine driven pump.

 

A vm 1000 trouble shooting manual is available at matronics

 

 

But, their server won't be up until the 6th.

 

Scott

 

I have been seeing indicated fuel pressures (9 - 13 PSI) on my VM1000 that are too low for the fuel servo (requires around 20 PSI) to operate at - but it continues to operate.

So after checking and modifying the fuel lines (changed from series to parallel for the boost and mechanical pump), removing the mechanical fuel pump and having it checked out at the manufacturer, we decided to just replace the fuel pressure sensor - figuring it would be under $100 to replace.

 

I called JP Instruments and got a quote of $650.  Holy crap.

 

The technician told me I could field-test the sensor and that it has an output of 1mv per PSI input.  ie 5 mv for 5 PSI, 10 mv for 10 PSI, 50 mv for 50 PSI etc..

 

Does anyone out there want to sell a working-but-not-using VM1000 fuel pressure sensor (the higher pressure one) for fuel injected engines?

 

Does a guy have any options or FP sensors other than VM1000 brand that put out that kind of output?

 

Randy Hartman

LNC 2 - N360DE - 450 hours