Why Did My Oil Pressure Gauge Quit Working??

[Dave1]

A local garage did an engine swap for me and now the stock oil pressure gauge on my 1986 GMC 3/4 ton 4WD pick up truck will not work. They have ordered and tried three new sending units with no success.

When the lead wire connector is pulled from the sending unit the guage needle goes all the way to the right and pegs past the 60lb mark. When the lead connector is plugged in to the oil pressure sending unit the needle comes back to the zero position like normal but when engine is cranked no oil pressure is registered on the guage. They unscrewed the sending unit, cranked the engine and oil squirted everywhere so it appears there is good oil pressure in the new rebuilt engine that incidently has a new high volume oil pump installed.

Would the high volume oil pump build up more oil pressure than the standard oil pump and may have ruined my 60lb stock guage? Wrong sending unit?? I am and they are puzzled.

Any ideas??

Thanks, Dave
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[sweetk30]

i had hv pump in my 60 psi gauge setup. worked o.k. but the big question is yes we know there is flow at that port but is there any pressure ? need to put in a manual gauge and check the pressure . i have seen oil flow threw a motor but build no pressure. if 1 plug or bearing is in wrong it wont build the correct pressure . just check the oil pressure with a manual gauge first. then check the cab to motor ground strap to see if thay reattached it.

and you said when conected it goes to zero, but when off the tab it goes full pegged. this is normal oporation . sounds like oil problem to me.

 

[Dave1]

The problem with my oil pressure guage was the mechanic had broken the spade off the back of the sending unit. Replaced with new sending unit and now the oil pressure guage registers fine. Idles at 45psi, goes up to about 65psi with any increase in engine speed.

Have some other issues to work out though.

Dave1
[email protected]