How to convert your oil pressure gauge (with pics)

[v8_superbirdy]

Originally Posted by XR7-4.6

The PCM has no oil pressure input, the factory sender is only for the gauge.

wow thats lame seems like there should be an idiot light for something as crucial as that...i dont have a oil pressure gauge though as im 97 so i put one in have to say its a very nice feeling be able to see my actual oil pressure.

[carcrz]

good job dude

[NetKeym]

After reading all this thread about the "fake gauge", I have to share this story with you all. First off, I had no idea they even made fake gauges, now I know different and I thank you all. I WILL be changing my sender and modding my dash in the very near future on my '95 LX. Now, the interesting story.

I came across my T-Bird about 2 years ago. When I test drove it, I thought "wow, this car is pretty powerful". I had owned a '97 about 5 years ago that had nowhere near the pep this car has. This car will spin the tires from a dead stop! Anyhow, the seller told me he was selling it cause his "mechanic friend" told him that the oil pressure was getting low and it was going to have a "massive engine failure" in the near future. Well, I have noticed (while I've been driving the car around for 2 years...lol) that the gauge does read real low sometimes, but most of the time, it stays about half way.

After reading this thread, I realize it's probably a connection or the resistor failing. Thanks again all, and I hope you found the story as entertaining as I did!

[rbrown]

Originally Posted by NetKeym

After reading all this thread about the "fake gauge", I have to share this story with you all. First off, I had no idea they even made fake gauges, now I know different and I thank you all. I WILL be changing my sender and modding my dash in the very near future on my '95 LX. Now, the interesting story.

I came across my T-Bird about 2 years ago. When I test drove it, I thought "wow, this car is pretty powerful". I had owned a '97 about 5 years ago that had nowhere near the pep this car has. This car will spin the tires from a dead stop! Anyhow, the seller told me he was selling it cause his "mechanic friend" told him that the oil pressure was getting low and it was going to have a "massive engine failure" in the near future. Well, I have noticed (while I've been driving the car around for 2 years...lol) that the gauge does read real low sometimes, but most of the time, it stays about half way.

After reading this thread, I realize it's probably a connection or the resistor failing. Thanks again all, and I hope you found the story as entertaining as I did!

Since it's a 95 it's probably 3-4 quarts low from burning oil.
Just kidding. Sorta. Check your oil.

[CrystalPistol]

Originally Posted by rbrown

Since it's a 95 it's probably 3-4 quarts low from burning oil.
Just kidding. Sorta. Check your oil.

Very possible.

[rbrown]

Originally Posted by CrystalPistol

Very possible.

I know mine was 3 low again the other day. I don't know how it still runs.

[tbirdguy]

Originally Posted by rbrown

I know mine was 3 low again the other day. I don't know how it still runs.

would you believe after new valve seals it loses about 1/4 qt of 5w20 in almost 3000 miles?

[rbrown]

Originally Posted by tbirdguy

would you believe after new valve seals it loses about 1/4 qt of 5w20 in almost 3000 miles?

Just seals huh.... hmmmm.

Rodney

[NetKeym]

Originally Posted by rbrown

Since it's a 95 it's probably 3-4 quarts low from burning oil.
Just kidding. Sorta. Check your oil.

Yes, the car uses oil, but I keep an eye on that...lol I found the reason the gauge was flaky when I took the dash apart. I took it apart cause the bulb went out by the oil pressure gauge. Well, the bulb was good, just a connection had deteriorated on the ground for the gauge AND the light. Cleaned that up, now the idiot gauge stays right in the middle and the light works.

Now I bought the correct pressure gauge (I got a BWD S334 like tbirdguy) from o'reilleys and I have to take the dash apart again *sigh*. BTW, that 20 year old plastic is VERY brittle on my 95 so it sucks to disturb anything!

From what I understand from you all, the valve guides are shorter on the 1995 4.6 T-Bird heads and wear out quickly causing the valve seal leakage problems and subsequent oil consumption. I just keep feeding it oil. That Motor Honey engine treatment really helps. I used to have to add oil once every couple weeks, now I can go almost 2 months.

[geoph1986]

How would this work with a digital cluster on an '89 Cougar LS? Is the resistor by the oil sender or is it part of the cluster circuit board?

[tbirdguy]

Originally Posted by geoph1986

How would this work with a digital cluster on an '89 Cougar LS? Is the resistor by the oil sender or is it part of the cluster circuit board?

Probably not(but I'm guessing). The 20 ohm resistor just acts to position the pointer (which is a voltmeter or ammeter) into the normal range on mechanical gauge.

There are two possibilities(and tips to experiment):

1)If there is a true analog to digital converter in the cluster(like the temp gauge), you can connect a variable resistor with say 0 -100+ ohms and see if the bars change. This experiment will determine if there is an analog to dig converter. Or just buy the oil sender and see if it works. You may have to place another resistor in series or parallel to get it to work thru the range (like biasing).

2)If it is just wired to light up 1/2 the bars if the on/off switch registers oil pressure(eg 14 volts), then you have to do some engineering and get a hold of a VU-level meter type integrated circuit which can light up the segments as the voltage changes. I wanted to do something like that for the auto 4x4 on my explorer, as the coil energizes and locks the clutch in the xfer case, I would have a bar graph showing engagement.

That assumes you can control each segment individually (there is no multiplexing on the display).

I believe these cars have the 20 ohm in the wiring harness by the oil sender, not sure about the digital ones though.

[beamerboy46350]

Wow Great read cant wait to do it!!!

[The_coop_08]

Props for a fantastic mod!!! Now i can see how good my oil pressure really is with the new motor.

[thunderhawk97]

allright then,i have a wierd question then...after reading all this...my guage seems to a bit far from the norm..my 96 lx 4.6 oil guage works quite the opposite..it works like an oil guage should...up and down with the speed of th engine..so im confused now..did i miss something?

[Melon]

If it moves (and you haven't modified the gauge yet), either by some odd chance it's already been done OR your oil pressure unit is going bad or the wiring is slightly loose. I'd bet money on the wiring or the sending unit.

-Melon

[Al_Florida]

^ What he said because your car has a dummy gauge.

[LoadedButane]

I just did this mod yesterday and it was easy as pie. $10 for being able to actually gauge the oil pressure rocks.

[theterminator93]

Anyone have any luck finding a way to get the sender to fit on the 3.8s?

[rbrown]

Originally Posted by theterminator93

Anyone have any luck finding a way to get the sender to fit on the 3.8s?

I did my SC the other day. No sure if the brackets are similar. I used an extension to mountthe sender to the factory extension. Puts the sender about an 1-1/2" further out and not bumping into anything.

[theterminator93]

Cool, I thought I read somewhere that an extension or pair of elbows was used to clear the alt/PS pump bracket but I wasn't sure.

Here's a picture just in case (yes, I know the serp is toast, and uhh, I snapped the head of the old sender off too ):

[theterminator93]

Okay, managed to get it thrown together this afternoon. Here's what I ended up doing for you guys with the 3.8s:

I ran up to Home Depot for a few fittings this morning to try and build some kind of extension that made some sense. What I ended up using was a 1/4" x 2" brass nipple (Watts P/N A-742) threaded into the extension coming out of the block into a 1/4" coupling (P/N A-732). That threaded into a 1/4" MIPx 1/4" FIP 90 degree street elbow (P/N A-739) pointed towards the bottom right, then into the sending unit. I did have to extend the lead a couple inches, but it works just fine. I had to thread the extension and elbow into the coupling before screwing it into the extension on the engine. It was a tight fit getting it in tightly and at the right angles, but it worked out well enough.

The sender I used was the S334 from Advance Auto. I placed my order online and selected in-store pickup and used the P20 code for 20% off, so I got the sender for $8.31. For the three fittings I spent $8.42, so in total this set me back only $16.73. Here are a couple pics:

[Earl]

After many years of lusting over this cool mod, I Finally did it...used the factory motocraft sending unit...

I had to do some adjusting and wiggling to get the wiring to stretch far enough to fit...the wire it real tight, which i don't really like, but we'll see about fixing that up.

Soldered the jumper wire onto the cluster and the guage behaves like a real oil guage now
I did, however, dump the contents of the oil filter onto the driveway when I unscrewed the fake sending unit and I had to unscrew the real sending unit because I lost the wire above/under the sending unit the first time I scrwed it in, so, hopefully I didn't screw it up, as in, having to re-apply new teflon tape....we'll see.

So far so good...can't drive the car though since a tire decided to die tonight...