2000 Mercruiser 3.0 no oil pressure

[Dion Schoening]

I have a 2000 3.0 mercruiser. Added an electric fuel pump with a 7 psi oil pressure cut off. Added a T. so I can run both the relay and standard oil pressure sensor to the dash gauge. everything has been running fine. Recently, the T broke and and the engine shut down due to no pressure to the fuel pump relay. Got everything cleaned up and fixed. started up and ran briefly but no oil pressure on gauge. I checked the guage by grounding and the oil pressure gauge pegs out. I replaced the sending unit thinking it may have been damaged when the T broke off. I have a manual guage on order to check pressure. The things that is puzzling is it will run which should mean I have at least 7 lbs of oil pressure for the relay to close for the fuel pump to work. Like I said I have a manual gauge coming in and will check this weekend. just wondering if anyone has any ideas i can ponder as possible fixes to look at while I work on it this weekend.

 

[Bt Doctur]

If the electric fuel pump is coming on ,you have some oil pressure, install a mechanical gauge to verify

 

[Scott Danforth]

how long did it run without oil?

 

[QBhoy]

How did you wire in the minimum 7 psi add on idea ? Is there a chance you’ve compromised the oil pressure sensor by doing this ?