Here's a dumb question.

[2003_MM_FYRE49]

Has anyone tried replacing just the oil switch, with an oil sender and seeing if our oil pressure gage would work that way? Just curious.

Tim :fire: 49

[WolfeBros]

Yes. It will not work as a real gauge even with a real sender.
The MM gauge was designed to be basically an on/off type of indication. When the OEM sender sees pressure above 6 1/2 psi it goes to ground. When it goes to ground the gauge will always read 65 psi. Think of it as an analog idiot light.

If you want a working Oil Pressure gauge you need to change the gauge and the sender.

A real sender has a variable resistance that changes with a change in oil pressure. A fixed voltage goes thru this resistance and is read as current on a D.C. milliamp meter that is calibrated to indicate pressure.

FYI......a temperature gauge and even a gas gauge works on basically the same principle. (although gas gauge sender is a float and does not read pressure......its still a variable resistance.)

[Murader03]

Originally posted by 2003_MM_FYRE49
Has anyone tried replacing just the oil switch, with an oil sender and seeing if our oil pressure gage would work that way? Just curious.

Tim :fire: 49

Tim:

My Dad, rest his sole, my DI in boot camp way back when, and a lot of folks smarter than I'll ever be always told me: "There is no such think as a DUMB question! So, whith that in mind, don't ever be afraid to ask.....You might get a smarta$$ answer from some at times, but you'll always get an answer to you questions.

[Marauder57]

Just as a ball park...and not really directed at a vendor....what would a working Oil gauge installed cost? Do you think?

[WolfeBros]

Tim.....I didn't consider your question dumb. Hope my response didn't come off that I did.

Murader, I agree with your Dad. THere is no such thing as a dumb question.

57,
I would guess that someone would do the install for you for around $50 to $75 bucks if you supplied the gauge. But its just a guess. I always did this type of work myself. A call to a speedshop would probably answer this. Good luck

[TripleTransAm]

Originally posted by WolfeBros
Yes. It will not work as a real gauge even with a real sender.

I believe some of you already tried this, but I had to see it for myself out of sheer curiousity. Engine off, pressure read something like 25. Engine on, not very hot but not cold, read close to 35.

Internally, I could only see the differences between the working and non-working gages being a resistor on the replacement gage and possibly one teeny tiny wire on the factory one.

I was toying with the idea of adding the resistor to the factory unit and seeing how functional I could get it, but I ended up trashing the extra factory gage I bought when extracting some of wires and terminals through the plastic holes.

[2003_MM_FYRE49]

Originally posted by WolfeBros
Tim.....I didn't consider your question dumb. Hope my response didn't come off that I did.

Wolfe, I know you didn't consider my question dumb, nor did I think you came off that way at all, because I'm not an electronics expert I figured I'd field the question to see if using the OEM gage with a new sender would work. I guess what amazes me is that Mercury went through all the trouble to have Auto Meter produce a fake gage when it would have been much cheaper to install the real thing. My cost through the Ford Dealer I trade with for an OEM AM gage is $85.00 plus tax, and I bought the Real AM gage for $72.00.... Hey Ford, instead of decontenting these cars, why don't you look in a more reasonable place to cut cost!