QuestionMy oil pressure gage is showing erratic behavior, from near zero to almost 50. My local mechanic, who can normally solve this, says I need a "oil sending unit w/ gage" Call Victoria British, my trusted supplier, and they say they don't carry those. If they exist, who carries them?
AnswerHi Jim,
You first need to test to see what is wrong before buying parts.
First thing to look at is the power supply which is 10v not 12v. Also you need to confirm that the gauge in the dash has it's ground on it and it is a good ground. Next thing to check is "Do the fuel and temp gauges work normally? The reason is that all three are powered by a "Voltage Stabilizer" that produces 10v.
If the other gauges operate normally then the power supply is working normally but you still need to confirm that the connection on the oil gauge is tight and that the ground is a good ground and secure.
If all that is correct you should turn on the Ignition key (on not start) and watch the oil gauge. Then remove the wire from the sending unit and note the needle movement on the gauge. It should deflect all the way in one direction then ground the wire and watch the gauge.
DO NOT CONDUCT THIS TEST BY GROUNDING THE WIRE AND THEN GOING TO LOOK AT THE GAUGE! YOU MUST HAVE SOMEONE WATCH THE GAUGE WHILE YOU RUN THE TEST BECAUSE LEAVING THE WIRE GROUNDED CAN DAMAGE THE GAUGE. YOU CAN ONLY TOUCH THE WIRE TO GROUND FOR A SECOND.
It should deflect all the way in the opposite direction. That is a preliminary test of the gauge. If it does deflect each way with the wire off and then grounded it is a good sign that the gauge is probably ok and it is either a loose or bad wire connection or a bad sending unit.
Your symptom sounds more like a loose connection as I have replaced a lot of sending units and some gauges and most that fail just quit working.
Howard
