[MrZ]

Hi everyone I need help Bad lol I have a 69 gto it had idiot lights and I went and put in rally gauges I did change the 2 wire up t the circuit board everything works as it should my problem is the oil pressure gauge here is what I did so far put in new sending unit 3 so far when I take plug off gauge goes to 80 I ground end of plug gauge goes to 0 fine gauge ok I start car oil pressure fine go for a ride all seems ok I bring car home shut it off and turn key on without starting the gauge wont go back to 0 stays about half way start car gauge goes all the way up to 80 shut car off take plug off put it back on all seems fine its driving me crazy is there another wires I am suppose to change ?? I even tried to ground sending unit out and still not correcting problem tried 3 new sending units all same thing any help will be greatly appreciated