Convert Dummy Oil Pressure Gauge to Real

[TallPaul]

I plan to do this to my Ford Ranger 2.3L: Dummy Gauge Fix
The question is, what sender to use. I would like to use most of the gauge sweep. My 2.3L 4 valve engine is specified by Ford to have hot oil pressure at 2000 rpm of 29-39 psi with 5w20 motor oil. I will be using exclusively Redline 5w20. I can get gauge senders in 0-100 psi, 0-80 psi, and 0-60 psi (and lower or higher). I am inclined to get a 0-60 psi so that at road speed it will read up the middle of the gauge. I figure with 5w20 it is not likely to exceed 60 psi or even get that close. If it does, the gauge will be pegged, but would not be ruined (so I am guessing) because the sender will not exceed the stated amount. Thoughts, comments, advice?

I don't have to do this, but it bugs the living whatever out of me to have that stupid fake gauge staring me in the face!

 

[abycat]

I put an aftermarket one in my truck too. I have a different sender than the stock one which is still there and the stock dummy gauge still works. My guage is in the dash and its a 0-100. It works great and the only other thing i need to do for my oil habit is to put a bung in my oil pan for my already mounted oil temp gauge. I also have an aftermarket coolant one too and that is a real nice addition as well. Its funny how the oil pressure really is and how the dummy reports it. My OP is from 20-55 and the dummy does not even move only from 0 when off and goes to the absolute middle mark. I would use a 0-80 psi sender for yours.

 

[CATERHAM]

To be accurate doesn't the sender have to be match to the gauge?

BTW, RL 5W-20 with it's HTHSV of 3.3cP will have the oil pressure of a mid-grade low VI 30wt oil. In reality that's what it is. RL really doesn't have a suitable oil for a true 20wt (HTHSV of 2.6cP) application. Even their lightest oil, RL 0W-20 with it's HTHSV of 3.0cP is still too heavy.
Suggest you stick with Motorcraft 5W-20 or upgrade to a 0W-20 syn' like M1 AFE 0W-20.

 

[JimPghPA]

For the gauge to be accurate, (at least for most gauges) the maximum pressure it is ever exposed to should not exceed 1/2 of the maximum reading. Unfortunately this leaves you with less resolution if the gauge is only going to read 1/2 scale at the maximum pressure you will use it at.

There are some gauges that can handle an actual pressure equal to the maximum reading, but they are more expensive. You can usually tell if the gauge can handle full pressure and maintain its accuracy, because the manufacturer will be bragging about it somewhere in the literature about the gauge.

 

[TallPaul]

Hmmm, well guess 80 psi is a better choice. I was going to go electronic and use existing gauge, but the cost will be more than if I do it myself with an aftermarket gauge mounted on the steering column. Maybe I'll do that instead. Problem is the electronic gauges have the 90 degree sweep, whereas mechanical has a 270 degree sweep(though 100 psi max)--much better and you can mount it so your range is at the top. I have done mechanical before with nylon tube but am thinking the copper tube may be better. What do you think?

I'll stick with Redline, I see no problem with it. If anything they may have an 0w20.

 

[SteveSRT8]

Be very cautious about running an oil line into the cab. Obviously if not done to a very high standard it can be interesting!

(please do not ask me how I know this)

Otherwise I am a BIG fan of real mechanical gauges as they reveal every pulsation and variance in the oil pressure.

 

[TallPaul]

Steve, you are right. I have run nylon for 8 years in the F150 I just sold, but changed the line after 4 years. Also I put a plastic tubing over the fitting that extended back over the line so if the line burst, hopefully the hot oil drains under dash, not pretty, but a hot foot is better than a hot face.

If I go with copper it is supposed to be much more secure, though I am not sure how the line end is secured. Easy to see ho the plastic deforms in the fitting to stay in place.

They are supposed to have very responsive electrical gauges these days, but mechanical is a tad simpler to hook up as the only electrical connection needed is the lamp.

 

[antonmnster]

One I rigged a temp mechanical gauge in my Saab 900 with a nylon tube running into the center console to the (unmounted) gauge. Of course the gauge fell off and oil pumped out the tube.

I grabbed an empty drink container and let it slowly fill on the drive home. When I got back, I just dumped the oil back in the crankcase. Glad it was really cold and the oil was thick!

I was 19 and it didn't bother me. But I also drove to CA and back with 2 lug nuts on each rear wheel. I should probably be dead...

 

[meep]

bigger than looking at pressure rating of the sender will be electrically matching the sender to the gauge!! The sender is a variable resistor, and the gauge assumes that for a given pressure, it will "see" a given resistance. If you get to mix and match, there should be some specs that need to match. i.e., 0psi = 500ohm, 50 psi = 300 ohm, 100 psi = 100 ohms, or whatever.

Newer electrical senders have changed.... my old electric suntune senders did not have a perceivable stairstep. they were a wiper against wound 30ga resistance wire... nice. the new one I slapped in our van probably jumps in 7psi increments. kind of crude.

I have a Sun sportST or somesuch waiting for the jeep. it's got a heavier sender, perhaps better resolution....

either way-- you need to see what kind of sender the gauge expects on the other end, or the readings will be bogus.

PS-- never had vinyl fail on me!

M

 

[TallPaul]

Given all the pros and cons including the fact that the dash "gauge" is almost hidden behind the steering wheel rim (one advantage of a tilt wheel), I think it would be much wiser to put in an aftermarket gauge. I have a perfectly good Sun 2" mechanical oil pressure gauge that I can use and some new nylon tubing (sitting in the package 8 years but that should not matter). Alternately, I was looking at these 1 and 5/8 face gauges which would be better to fit in on the steering column.

 

[mechtech2]

Get a gauge and sender to match.

 

[TallPaul]

Mechtech2: How do you feel about the mechanical gauge and nylon line? Line seems pretty safe and never had problems on the F150 with nylon.

What extra wiring for electronic gauge? Electronic gauges just dont have the big sweep though.

Wonder if my truck (2001) needs the sender for other stuff? I kind of doubt it. Could T it in. alternately, should be able to put a wire to it that is live only with key on, so when ever engine is on the gauge looks like it works.

But if I did jump the resistor, I have a real sender from a 1990 E350 460 V8 dash gauge. Funny even though a real sender the gauge was not responsive to the degree I put a mechanical in.

 

[TallPaul]

I just had an idea. For the fun of it, I have an oil pressure sender from a 1990 460 V8 that I will screw into the Ranger and see what happens. My thinking is that I will get needle movement below the middle of the gauge. Assuming 20 ohm resistor equates to 40 psi on the gauge (circumvented by full current from the switch, then I should get a reading for all but cold winter starts, when it may be above 40 psi. As the spec is 30-40 psi hot at 2000 rpm, this may work pretty well. On the other hand, it may not work at all. No harm trying.

 

[TallPaul]

Probably won't work as the experience of one guy on the Miata forum shows:

"OK, I've drove the car today for the first time since installing the VDO sender. After the oil gets good and hot the gauge needle drops to zero. Pretty scary. When it first happened I killed the engine and pulled over in an emergency sort of way and checked for an oil leak. Everything's OK. So, I've decided to calibrate the gauge."
http://forum.miata.net/vb/showthread.php?t=71880&page=2

These guys are pulling the gauge, why don't they simply jump the resistor? Don't they know?

But it apparently works quite well if you reposition the needle:
http://www.eng.hawaii.edu/~panos/my_oilpres.html