Oil pressure sender

[johnmi]

I have a new smiths classic oil pressure gauge and a new sender from Richard, the problem is it is reading 90 lb at tickover cold. I know the oil pressure is correct 40 - 50 lb because I have tested it with a fluid gauge. The sender states kn/m2 and the gauge lb/0. I have connected to 12volt as wiring diagram, but if I connect to 10volt I get the correct reading.

Thanks for any replies

[Grumblebuns]

Are you sure that you are reading the wiring diagram right? If I'm looking at the wiring diagram correctly, the oil pressure gauge is powered from the 10v voltage stabilizer.

[jbcollier]

Well, there's your answer, connect to the 10v supply.

[EuropaTC]

I thought all measurement type gauges apart from the voltmeters/ammeters/rev counters were 10v so they had a stable supply and didn't have to cope with variations from 12 to 14 volts with the alternator charge output and loads from wipers, headlights, etc ?

Brian

[jbcollier]

Many modern gauges have built in voltage stabilizers and can run system voltage and still give consistent readings.  Obviously, not this gauge.

[johnmi]

Below is a reply from Caerbont technical when i asked them the same question.

Hello,
The oil pressure gauge runs from the 12 volt ignition supply.
As regards the temp and fuel gauge, the purpose of the 10 volt regulator is to ensure a constant pointer position when the engine is started.  With ignition on, the supply voltage would normally be 12.6 volts, and 14.4 volts when the engine is started.  So if the fuel and temp gauges were driven from the switched ignition supply, the pointers would move.
However, as you only get oil pressure when the engine is started, Smiths specified that the oil pressure gauge should be calibrated for 14.4 volts.
Regards,
Ian

[johnmi]

As a side note to the last post the wiring diagram shows it coming from the 12 volt side of the voltage stabilizer, it is looped from the wire coming from the fuse box , the other side goes to the water and fuel which are 10 volt.

[Grumblebuns]

Looking closer, you are absolutely right on the power source for the oil pressure gauge, it does come off the 12v side of the VS. I would suggest giving Banks a call.

[jbcollier]

Then you are going to have to send the sender and gauge back to the vendor for replacement or recalibration.

Frankly, myself, if it is accurate at 10v, I would run it at 10v.  You have a 10v supply right there.

[johnmi]

I am 90 percent sure it is the sender I had an old smiths gauge that I connected and that did the same, but I might just run it at 10 volts and problem solved. The smiths sender are £40 - £50 strange though I spoke to Richard when I first had the problem in case he had had a bad batch but he says not. Thanks for the replies anyway