REFLECTOR: Oil Pressure

[John Dibble]

My sensor is on the bottom of my oil cooler and has a ground wire attached to it.  I
added a second ground wire which passes through the landing light.  Would it help if I
ran the ground wire directly to the battery or to the buss?

John

Laurence Coen wrote:

> John,
>
> Your oil pressure transducer is likely grounded at the engine and your
> readout is grounded to your panel buss.  I suspect the ground potential at
> the panel buss changes with change in load but the same thing doesn't happen
> to the engine ground.  You can check the voltage between the engine and buss
> grounds with varying loads.
>
> Larry Coen
> N136LC
>
> --------------------------------------------------
> From: "John Dibble" <aminetech at bluefrog.com>
> Sent: Friday, July 31, 2009 9:02 AM
> To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
> Subject: REFLECTOR: Oil Pressure
>
> > At this point I'm pretty sure I do not have an oil pressure problem.  On
> > the return from
> > OSH, my observant copilot noticed that every time I turned a knob the
> > pressure reading
> > changed.  So I turned off my radio and the pressure went up 6 psi.  Then I
> > turned off the
> > transponder and the pressure went up another 6 psi, making it 51 psig
> > which I am happy
> > with.  I checked the voltage drop across the relay and it is 0.  I checked
> > the voltage
> > drop between my RMI monitor ground and another ground.  I varied from
> > 0-0.02 v as I turned
> > on a few things.  The monitor power voltage decreased from 12.6 by 0.1
> > volt each time I
> > trurned on something.  I figure that's just the battery voltage going down
> > with increased
> > load.  What do I need to be looking at?
> >
> > John
> >
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