Oil Pressure or Oil Pressure Gage – 2005 Roadster

Hello All:

We recently purchased a 2005 from Dennis Glavis at Morgans West.  At the time he told me the oil pressure gauge was not working and he would order a new gauge and send it to me when it arrived; which he did.  (Old gauge did not register anything)

Installed it this morning, here is what is happening:

When I start the engine the needle on new gauge moves slowly across and pegs out past the “10” (past max reading).  When I shut engine off it slowly recedes back to zero  (takes about 15 seconds).  No mid-range readings.

Thoughts on what the problem might be? Anyone else have this problem. Appreciate input

John Stanley