Hey guys, thought I would tap the brain trust here. I have a push back at the airport that we put a new DD 453t in. The kid that pulled the old motor with the spun main bearing did not label any wires, except one...and that one says Oil PSI. There was a single different wire screwed down onto a Nason oil pressure switch, and also what was left of a broken terminal on the same lug. My guess is these others may have been for idiot lights? This switch has two pins (bolts/lugs/?)
With the ignition on, the gauge is maxed out. If I hook the single wire that says 'Oil PSI' to my original sender, nothing happens, it stays maxed out. However, if I jump that wire to any ground source, my gauge goes from max to zero readout. So I am pretty sure this is the correct wire to be using. If I put a test light on it, there is just enough resistance to drop the guage to about 60psi. From what I've read, if the gauge is reading max with the wire connected, it could be an open circuit, most likely the sender? Is there a reason I would need one of those other wires to complete the circuit? It is an old military unit and the wires are all white...argh.
Thinking that my sender was bad, I grabbed one off the shelf, it's a different style but figured why not. Now it reads about 20psi with key on, and starts dropping to zero as rpm's go up. But hey, at least it does something!
Why does it read backwards?
Brian Hobaugh SCCA National Tour June 2014
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