I just pulled my instrument panel out to troubleshoot an oil pressure gauge problem. Now my gas gauge appears to not be acting right.
How do I calibrate these gauges?

Second question: The oil gauge issue...
I set the gauge arm to Low as a starting point. When I gave power to ignition, the gauge arm moves backwards way past the LOW pressure mark. What is this telling me?

Thanks!!

 

I heard that disconnecting the battery or instrument cluster with less than 1/4 will cause It to lose the memory. Try filling the tank, disconnecting the batter for about a few minutes then reconnect it.

 

Check the printed ckt traces on the cluster. Probly one or more are bad when you had the cluster out. Problem sounds like a grounding issue. Also the IVR(insterment voltage regulator) could be going bad. Usually the other gauges will show the same problem if thats bad. Last but not least is the oil sending unit is bad. Those things usually fill up with oil and cause wierd readings before they start leaking oil out.


There is no real way to "calibrate" these gauges as they are not accuret to begin with.

 

Put it all back together. Go out and find the oil pressure sending unit. It's location will vary depending on what engine you have. If you have a 302 or 351w, it will be down near the oil filter and fuel pump.

Pull the wire off the sending unit. With the key in run, engine off, put the sending unit wire on to a good ground. The oil pressure gauge should swing full scale either high or low. Then take the wire off ground and let it hang in the air, touching nothing. The gauge should swing full scale the opposite direction. If it passes this test, then the wire and the gauge are good, and there is a problem with the sending unit.

This test will work for all the gauges. For the gas gauge, simply pull the wires off the tank, ground and un-ground the wire and the fuel gauge will swing back and forth if all is good with the gauge and the wire to the gauge. Same for the temp gauge also. It has a sending unit on the engine like the oil pressure gauge.

 

Well, I replaced the sending unit this evening but that did not fix issue. All the other gauges seem to be fine.
Where is the IVR located? This is a 1995 F-150.
I'll double check the cicuit traces tomorrow, I looked at them earlier today to make sure the gauge connections were seated on them, did not see anything unusual.
Running out of ideas... I suppose it could be the dang gauge itself.

 

Ah a 1995 truck, the oil gauge is not a actual gauge, its more like a idiot light. After 88 Ford made all oil gauges either show "normal" or low depending if the oil pressure is over 7 psi. There is a mod to make it work like a proper gauge, but you'll need to look in the 87 to 95 Forums, I have posted there about it.

 

You are not going to find a IVR on a 95 truck. But my tests are still valid for that year also. And the other poster is correct, your oil pressure guage is not really reading oil pressure like you think. It's either in the middle or it's on zero, no inbetween, it doesn't really really read the pressure on the later trucks.

 

yep, i understand it being an idiot light. My problem is that it reads way past the Low mark, I can manually move the hand to center gauge, and when I give power to ignition, the hand moves way left. When I take the cable off the switch, it does not move, when I ground it, it does not move. I put my Fluke meter on the wires and the wires have continuity, no open wires. I suspect something is grounding the signal wire some where.
I installed an after market gauge yesterday just to be sure I actually had pressure and all is good at 53psi.

 

"I installed an after market gauge yesterday just to be sure I actually had pressure and all is good at 53psi"

Smart move! Might consider a Coolant Temp gauge as well. Real mechanical gauges are the way to go....IMO

 

Yep, I installed a dual set with oil and water gauges... took some work, but all working good. I would just like to see the original gauge work as well. I took the time to put in "T" connections so that both original and aftermarket would work together.