2.3L ('83-'97) Oil guage questions

[John501]

Hey guys, I've got a 1990 ranger 2.3 2wd 5speed custom. When the engine is about a quart low on oil the guage reads below halfway. But once I too it off back to full it sits above half way. When I start the truck up it slowly comes up to above halfway. Unlike my 01 explorer that just clicks to the middle, since I know that has a dummy guage. I honestly can't figure out a straight answer, is it a real oil pressure gauge or a dummy guage on my ranger? On the ford truck group I found a lot of treads saying its a dummy guage. But I thought I'd come to the ranger pros, and ask. If it is a really guage what pressure do the letters of "normal" correspond to?

Thanks,
John

 

[scotts90ranger]

It's just a dummy unless someone in the past did some modifications (it's doable, apparently if you get a '78 Bronco sender and bypass a resistor on the back of the cluster).

Myself I just teed into the stock switch and put in a manual gauge. Just an FYI '90 was on the early side of the aluminum oil pan and they're known to have a bunch of silicone or oil pan gasket material getting into the oil pan and plugging the pickup tube, the first time I had the engine out of my '90 the pickup screen was nearly plugged... unfortunately the engine about has to come out to get the pan off... putting a manual pressure gauge is doable without pulling the engine, I put a gauge next to the center dash vent, that piece is just a dummy plug.

 

[tomw]

On the 2.3, the oil pressure port for the gauge or switch is located on the drivers side, rearward. If it has been changed to indicate actual pressure, it will be a bulbous domed gadget with an electrical fitting at its 'top'. A switch will be made of metal and black plastic. The switch looks exactly the same as the low pressure indicator light switch but works the opposite, closing when pressure is above 5 psi, while the light switch closes when pressure is 5 psi or below, turning on the light.
If you have the fallapart gasket that attempts to clog the oil pump intake, some have used a coathanger thru the drain plug hole to attempt to scrape away some of the deteriorated material.
So you can tell without a lot of effort if your gauge is a dummy or showing some relationship to actual oil pressure just by looking at the side of the engine. I don't remember if it is fitted to the cylinder head itself, but do know it is up higher than the coolant temperature gauge sender located a bit above the oil filter.
tom

 

[scotts90ranger]

Good point, pull the wire off the sender and ground it with someone else looking at the gauge with the key on.

 

[John501]

I tested it and it was just a dummy guage. So i put in a mechanical guage today. At a cold start, u get 55-60psi although there is still a little air in the guage so it's not a perfect reading. Is 60psi idel cold good, or bad?

 

[RonD]

You put in a PS-60 sender(on the engine) AND a mechanical gauge correct?

The gauge was not the "dummy", the oil pressure sender was, its an ON/OFF switch so its just a straight Ground when engine is running

In a 1990 you can pull out the instrument cluster and put a jumper wire on the oil gauge so it will be a "real" gauge and work with a PS-60 sender, same 1 wire setup

Looks like this when done: https://www.therangerstation.com/Magazine/spring2017/oil_pressure_gauge/ford_ranger_variable_oil_pressure_gauge_modifiction-3.jpg

PS-60 looks like this: https://dgzmd7u6z2by7.cloudfront.net/partimage/OSU/1AOSU00004/large.JPG
These have been around forever, and are cheap


60psi is a bit high, but if oil is cold enough and RPMs high enough it can show 60psi

General rule of thumb for oil pressure is 10psi per 1,000rpms after warm up

Oil pressure is the oil that the engine CAN NOT USE at that time
The oil passages and bearing gaps can only pass a fixed amount of oil

The "oil pressure" is what backs up in the main oil passage because it can NOT flow into the engine
You want at least 6psi at idle or hydraulic lifters will start to clatter
As RPMs go up oil pump spins faster so pumps more oil out, engine use of the oil doesn't go up that much more so the oil pressure goes up, so even more oil backs up in the main passage, lol

Anyway oil pressure is OK if its between 6 and 60psi but IMO 40-50 should be max
Over 70psi and you can "wash" bearings, the pressure causes bearings to actually dry out and fail

 

[scotts90ranger]

That sounds about normal for me, my turbo 2.3L is ~20psi hot idle and about 50psi cruise at 3000rpm, and on a cold start it does start out up there... new oil pump and bearings on the last rebuild, didn't measure bearing tolerances or anything fancy, just threw it together in a month or so... it needs a freshen up since it's, um, rustproofing itself...

And air in the line doesn't matter, air is compressible but you aren't measuring the flow, pressure is transferable through a compressible medium... pressure is simply a resistance to flow, since oil isn't compressible it just has that much resistance to get through the bearings as Ron said.

 

[John501]

You put in a PS-60 sender(on the engine) AND a mechanical gauge correct?

The gauge was not the "dummy", the oil pressure sender was, its an ON/OFF switch so its just a straight Ground when engine is running

In a 1990 you can pull out the instrument cluster and put a jumper wire on the oil gauge so it will be a "real" gauge and work with a PS-60 sender, same 1 wire setup

Looks like this when done: https://www.therangerstation.com/Magazine/spring2017/oil_pressure_gauge/ford_ranger_variable_oil_pressure_gauge_modifiction-3.jpg

PS-60 looks like this: https://dgzmd7u6z2by7.cloudfront.net/partimage/OSU/1AOSU00004/large.JPG
These have been around forever, and are cheap


60psi is a bit high, but if oil is cold enough and RPMs high enough it can show 60psi

General rule of thumb for oil pressure is 10psi per 1,000rpms after warm up

Oil pressure is the oil that the engine CAN NOT USE at that time
The oil passages and bearing gaps can only pass a fixed amount of oil

The "oil pressure" is what backs up in the main oil passage because it can NOT flow into the engine
You want at least 6psi at idle or hydraulic lifters will start to clatter
As RPMs go up oil pump spins faster so pumps more oil out, engine use of the oil doesn't go up that much more so the oil pressure goes up, so even more oil backs up in the main passage, lol

Anyway oil pressure is OK if its between 6 and 60psi but IMO 40-50 should be max
Over 70psi and you can "wash" bearings, the pressure causes bearings to actually dry out and fail

I just did a mechanical guage for now, no ps-60 sender since I didn't want to take the dash out yet. Once the truck is warmed up, it runs 40 idle then 50-60 going down the highway. Thanks for the details on how todo the ps-60 and jump the dash panel. Once it warms up again I'll do that.

 

[John501]

That sounds about normal for me, my turbo 2.3L is ~20psi hot idle and about 50psi cruise at 3000rpm, and on a cold start it does start out up there... new oil pump and bearings on the last rebuild, didn't measure bearing tolerances or anything fancy, just threw it together in a month or so... it needs a freshen up since it's, um, rustproofing itself...

And air in the line doesn't matter, air is compressible but you aren't measuring the flow, pressure is transferable through a compressible medium... pressure is simply a resistance to flow, since oil isn't compressible it just has that much resistance to get through the bearings as Ron said.

Okay, good to know I'm in the normal range for the truck. I wasn't sure how air could effect it, but what you said makes sense.

 

[scotts90ranger]

I lost oil pressure with the turbo engine, I'm pretty sure it has to do with the oil going to the turbo... As far as I know I was using the stock '90 oil pump in my first turbo engine since the stock turbo oil pump wouldn't fit in the oil pan and it always had high oil pressure, so did the N/A engine.