Mitsubishi Repair: oil pressure light comes on, oil gauge, fuse box

Question
1995 Eclipse turbo 5 speed manual.  I just finished rebuilding my 1995 eclipse turbo.  I fired it and started inspection for leaks etcetera, adjusted the Idle, all looked good.  As soon as I pulled out of the drive way the oil pressure idiot light came on.  I parked it.  Tore the engine down paritally.  Looks good. Took out the sensor and cranked it with the stater, oil flows.  Changed the sensor.  Light still on.  Using 5w-30 Mobile 1 oil.  Any thoughts.  This motor has 10 minuets and 100' on it.

Answer
Bill,
Sounds like you did everything correctly.  This might be an eletrical problem.  Be sure you have the wire going to the pressure sensor and the wire going to the gauge sending unit are attached properly.  If you have the factory service manual, it will show the eletrical circuit you can trace to be sure it's getting connectivity.  Also, the factory service manual will describe the procedure to test your pressure sensor and gauge unit when off your car.  A common cause for that light to come on is due to a lack of oil.  On a rebuilt engine, you should prime the oil pump and engine before starting it up.  The easiest way to do this on your car is to remove the MOTOR fuse in the fuse box under the hood.  Your motor can now crank over without fuel or spark.. Do this for 3 10-15 second intervals until you prime the motor with enough oil. Plug your fuse back in. After waiting about 15-20 minutes, check your oil level and top it off again if need be.

If you were to run your engine and your engine really was not getting enough oil, it will quickly start to overheat and you'll see and hear your coolant boil out of your overflow tank.  But if your light stays on, and your engine is running properly (your oil gauge stays between the LOW and HIGH marks), then it means it's an eletrical problem that you'll need to trace to its source.
Good luck!