Logo
FULL SITE MENU

Oil pressure reads 80 psi constant

D

driberich

New member
I have a 2005 four winns with a 5.0 GL VOLVO. The boat is new to us. The oil pressure reads 80 psi when ignition is on but not started. ( drops to about 30-40 when off) It also reads 80 psi when started. A boat mechanic replaced the gauge but still reads 80. I checked the ohms at the sending unit and off the engine it reads 250. Installed it reads 250 but when key ignition is on, it drops to 33 ohms (making the gauge read 80 psi) I have tried a new sending unit with the same results.

Just for reference, I hooked a mechanical gauge to the engine and it reads 50 psi at idle and increase as the rpm’s do.

Boat mechanic says the older anolog gauges read inaccurate and nothing can be done. ( I just have to live with it)

Any insight on this???
 
FWIW, you can't make an accurate ohm measurement on a circuit that's powered ON...usually best to isolate any unit as well (disconnect wires).
You can test the gauge with dedicated resistors - 240 ohm will show MIN value on gauge, 110 ohm show drive the gauge to the mid-point, and 33 ohm should cause full scale reading. resistor between S and Gnd terminals with gauge powered on.
if the gauge is good, you have two other items, the sending unit and the wiring connecting them.
there is typically no adjustment on most gauges. There absolute accuracy isn't bad, especially when the cost is factored in.
 
sounds like a wiring issue to me.
what you measure on the sending unit is reasonable.
what does the gauge read, with the key on and the engine OFF? should be zero. if not, remove the wire from the S terminal and see if the gauge goes to zero.
 
It is a multi function gauge. It reads oil, water, fuel level and voltage. One 12v wire powers the all the gauges. Which one is the s terminal? Is that the 12v?
 
the S terminal I referred to is the terminal that the oil pressure sender unit connects to. you will have to look at the tech data for your gauge to get that insight...
 
Back
Top