So,

Thanks to responders on this forum, I have come to the understanding that my oil pressure gauge is an idiot light with a needle.

Is it correct to say that to have a gauge that displays true oil pressure you would need a sender unit that actually measured a range of pressure, say 0-100 psi?

Is it also correct that the existing pressure sensor cannot accomplish this task?

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1989 XLT 4x4
5 speed Mitsubishi
2.9L

In the late 80s or early 90's, Ford converted the gauge wiring from using a variable resistance sending unit to an on/off sending switch and a fixed resistance. I'm not sure of the exact date when this happened but, FWIW, the 1989 Ranger EVTM wiring manual (published in 88) shows it as a "real" gauge.

You can easily confirm whether your 89 gauge is real or not. Look for a white/red wire going to a component screwed into the lower driver side of the 2.9L engine block.

• A gauge that reads actual pressure uses a PS60 sending unit that looks like a stamped metal cylinder, roughly 2+ inches in diameter.
  
• The simple on/off sending switch that was used later is much smaller.

If desired, the first few years of "idiot gauges" can be converted to read actual pressure. All that's needed is a PS60 sending unit and a jumper across a 20 ohm resistor on the back of the cluster.

(97 and newer Ranger OP gauges cannot be modded this way because they were rewound to read 40~50% at full battery voltage. They use the same type of on/off sensor that the 96-back has but there is no fixed resistor. I swapped 95 gauge guts into my 2003 cluster along with a real sending unit to make it show actual pressure.)

__________________
2003 FX4 Level II, Supercharged 5.0L V8, Headers, Duals
BW4406 manual transfer case, Aussie Locker, Torsen L/S, 4.10's
Bilstein 7100 rezzies, Cadillac/Mustang rear discs, Duff traction bars
Keypad Entry, Lock LEDs, ABS switch, sway bar discos
Heated seats, Explorer EATC, Trip Computer and consoles

2003 XLT 2.3L M5OD-R1 reg cab, 2011 Taurus SEL, 2016 C-MAX Energi Plug-in Hybrid

The other option is to get an after market guage and install it with a t-fitting to where the OEM sender screws in. It's been a while since I've checked but there were too options. You could go with either an electrical unit or a manual one that uses a plastic tube going from the sender to the back of the guage.

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Sgtsandman's Work in Progress
2011 Ranger XLT, 4X4, 4 door Super Cab. 4.0L, 5 Speed M50D-R1HD, 3.73:1, 8.8" open differential, Jason Pace cap
2019 Ford Ranger STX FX4, Super Crew, 2.3L Ecoboost, 10 speed automatic, 3.73:1 with rear locker, Leer 100XR cap

Just checked and the truck has the small sender, perhaps 1-1/8" in diameter.

The truck has what sounds like one loud lifter that acts up intermittently.
I thought an accurate oil pressure reading would help determine a course of action. (Current course of action is live with it.)

Thanks rwenzing and sgtsandman for the excellent info.

__________________
1989 XLT 4x4
5 speed Mitsubishi
2.9L

Bob is the man!

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If you do decide to turn it into a real gauge, this 93 3.0L how-to should get you started. Just adjust the instructions for your 89 2.9L.

http://rogueperformance.com/oilsw.html

__________________
2003 FX4 Level II, Supercharged 5.0L V8, Headers, Duals
BW4406 manual transfer case, Aussie Locker, Torsen L/S, 4.10's
Bilstein 7100 rezzies, Cadillac/Mustang rear discs, Duff traction bars
Keypad Entry, Lock LEDs, ABS switch, sway bar discos
Heated seats, Explorer EATC, Trip Computer and consoles

2003 XLT 2.3L M5OD-R1 reg cab, 2011 Taurus SEL, 2016 C-MAX Energi Plug-in Hybrid

why the hell does ford, and i guess other manufacturers continue to bullshit us with an "oil pressure gauge" when it is nothing of the sort.

i read somewhere that people were complaining about the low pressure readings at idle, which of course, are quite normal.

rather than explain that a pump turning slowly makes less pressure, they take this route.

is there a real idiot light along with the faux gauge? at least an actual idiot light is noticeable. i would much rather have it than the bullshit gauge.

guess i will have to look into modding my current cluster one of these days, or better yet, buy an earlier cluster sinc I also would like to have a tach.

am i correct in assuming a 94-96 cluster with tach is plug and play in my 97? and if i change the sending unit, will be an actual OP gauge?

1) People have been convinced that, in order to be perceived as savvy consumers, they should demand a truck with a full gauge package to enable them to know what's going on under the hood.

2) Unfortunately, many of those same people don't know anything about oil pressure or how an oil pressure gauge normally behaves. This ignorance can cause customer satisfaction issues and may increase warranty costs when dealers try to fix non-problems.

After a few years, Ford went on the defensive and gave us the feel good, on/off "gauge". It basically tells you whether the engine has any appreciable amount of pressure or virtually none. I don't like it either but I understand Ford's reasons.



98~2003 tach clusters also have a red "Check Gage" light that comes on for low oil pressure, low fuel level or high coolant temp. I don't believe that the 95~97 clusters had it though.



There were a few differences in the 95~96 cluster that can cause headaches when the complete cluster is swapped into a 97~03. [The 93~94 cluster is a completely different design and shape and will not fit a 97.]

If the 95~96 oil pressure gauge is transplanted into the 97 cluster and a sending unit is substituted for the sender switch at the engine, it would be possible to have a functional oil pressure gauge in a 97 cluster. As I said in a post above, I have 95 OP gauge guts in my 2003 cluster and it works well.

__________________
2003 FX4 Level II, Supercharged 5.0L V8, Headers, Duals
BW4406 manual transfer case, Aussie Locker, Torsen L/S, 4.10's
Bilstein 7100 rezzies, Cadillac/Mustang rear discs, Duff traction bars
Keypad Entry, Lock LEDs, ABS switch, sway bar discos
Heated seats, Explorer EATC, Trip Computer and consoles

2003 XLT 2.3L M5OD-R1 reg cab, 2011 Taurus SEL, 2016 C-MAX Energi Plug-in Hybrid

So what you are saying is that I could I keep my cluster and just swap out the OP/Voltage pod with one from a 95-96?

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1987 2.3/TK5, 125K.

That's what I did and also swapped a real sending unit in place of the factory on/off pressure switch.

__________________
2003 FX4 Level II, Supercharged 5.0L V8, Headers, Duals
BW4406 manual transfer case, Aussie Locker, Torsen L/S, 4.10's
Bilstein 7100 rezzies, Cadillac/Mustang rear discs, Duff traction bars
Keypad Entry, Lock LEDs, ABS switch, sway bar discos
Heated seats, Explorer EATC, Trip Computer and consoles

2003 XLT 2.3L M5OD-R1 reg cab, 2011 Taurus SEL, 2016 C-MAX Energi Plug-in Hybrid

What sending unit would I get for a 2000 2.5L? Would I just use one from a 95 also? Part numbers would be amazing.

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Automotive Electronics Engineer
2000 XLT 2.5L A/T
Mods:
Explorer OHC
Explorer Autodim Mirrors w/ Autolamps
Explorer Sport White Face Gauges

No, the 95 used the same style on/off switch as your 2000. You need a variable resistance sending unit.

Because of clearance issues near the A/C lines in my 4.0, I used a narrow Chrysler-spec PS210 sending unit. The problem is that the PS210 sender's resistance curve was not matched to the gauge calibration. So, for mine, the needle position and a resistor had to be changed in the 95 gauge to make it read in a reasonable fashion. Since it was already set up, I have continued to use this sender with my 5.0 conversion.

In an application with more room available or with remote mounting of the sending unit, I would try the larger Ford-spec PS60 that was used on mid 80's Rangers and many other Fords throughout the ages. There's no guarantee that the resistance curve of the PS60 sending unit would match the 95/96 gauge but my guess is that it would.

The PS60 and PS210 are part numbers for replacement senders from Standard Products. There are many other equivalents available. Any parts store should be able to cross reference them.


PS60







PS210

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2003 FX4 Level II, Supercharged 5.0L V8, Headers, Duals
BW4406 manual transfer case, Aussie Locker, Torsen L/S, 4.10's
Bilstein 7100 rezzies, Cadillac/Mustang rear discs, Duff traction bars
Keypad Entry, Lock LEDs, ABS switch, sway bar discos
Heated seats, Explorer EATC, Trip Computer and consoles

2003 XLT 2.3L M5OD-R1 reg cab, 2011 Taurus SEL, 2016 C-MAX Energi Plug-in Hybrid

95-97 does have the check gauge light. Tach models do. Non-tach does not. fyi

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Another easy way to tap into for a real pressure gauge is to by a sandwhich adapter from summit. http://www.summitracing.com/parts/TRD-1313/

This is what we are doing on my dads ranger. He didn't want to piss with getting the stocker out, puting in a "T" and reassemble. What we are doing is drill/tap into the side of the adapter for 1/4" pipe thread. Screw in oil gauge. Screw in two nipples and loop a hose to itself. This also adds the ability for an oil cooler down the road, oil tap for a turbo maybe.

We also use an oil gauge and water temp gauge on the pillar.

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Ball Joints/Upper A-Arms How To
Replace Door pin/bushing
Repair broken dome light tabs
VIDEO OHC Install

Thanks for the clarification. I checked the factory wiring diagrams and, FWIW, they show the "Check Gage" light in 96 and 97 but not 95.

__________________
2003 FX4 Level II, Supercharged 5.0L V8, Headers, Duals
BW4406 manual transfer case, Aussie Locker, Torsen L/S, 4.10's
Bilstein 7100 rezzies, Cadillac/Mustang rear discs, Duff traction bars
Keypad Entry, Lock LEDs, ABS switch, sway bar discos
Heated seats, Explorer EATC, Trip Computer and consoles

2003 XLT 2.3L M5OD-R1 reg cab, 2011 Taurus SEL, 2016 C-MAX Energi Plug-in Hybrid

Hey Bob, I've got another question: The PS60 (just by looking at the pic, looks like its for a mechanical gauge), also does the PS210 have the same electrical connector as the Rangers or did you have to splice in a new connector?

__________________
Automotive Electronics Engineer
2000 XLT 2.5L A/T
Mods:
Explorer OHC
Explorer Autodim Mirrors w/ Autolamps
Explorer Sport White Face Gauges