Low oil pressure

Johnnyboiranger22 · Jun 9, 2018

So ive got timing correct and i let my ranger run for atleast an hour since it the first real time its ran since ive owned it, i noticed the oil pressure beedle starting going back and forth and check engine light came on and oil pressure needle went to red and read low truck was running like a kitten and it still was. But whats going on?

bobaloo · Jun 9, 2018

Cheap and easy?

I had a similar problem. It was the sending unit on the motor. Could be the gauge, of course, but probably not. You could get a mechanical gauge and check it that way too. Just the quick cheap way of checking.

I'm sure you already changed the oil and filter, right?

Will · Jun 10, 2018

The dash gauge is really just an idiot light. It isn't an instrument that reads oil pressure.

I've never had a Ford that didn't have the Check Engine light on. We have a 2013 Focus and that light is on. My youngest daughter wanted me to paint my Ranger amber to match the check engine light.

To be honest, I didn't fully understand your comments. Driving with no oil pressure is bad. I always put mechanical oil pressure gauges on engines I was worried about. Don't trust what you see in the dashboard.

tomw · Jun 10, 2018

Check the oil pressure with a mechanical gauge. The pressure port is on the side of the cylinder head, drivers side, rearward. Single wire, push on connector.
Unless it has the 'domed' sender, it is a on/off switch.
If you have an oil pressure light, the switch opens with 5-8psi of oil pressure, closes, (turns on light) when less. If you have a gauge, the switch closes with 5-8psi of pressure, and allows juice to go through a resistor that will put the gauge needle 'in the middle'.
If you have the domed sender, the gauge reads an approximation of actual pressure.

If the CEL or SES light is enabled, read the codes. There are gadgets you can purchase to plug into the EEC-IV port, and read the codes. You can also use a VOM, preferably analog. The needle will move in response to pulses, which you observe & count.

Gnawbone: Any FoMoCo product built during(after?) the 1995 model year should have an OBD-II port to read diagnostic and trouble codes. In many states, you would not get a registration renewal with either light enabled. Hoosier State may allow renewals, but I'd bet they will soon be swayed by some group to require repairs even on FoMoCo products.
I have 4, and none have either light lit, though the Ranger doesn't have one... HA! (chuckle, its too old, but does have EEC-IV)
tom

Johnnyboiranger22 · Jun 10, 2018

Thanks guys im going to try replacing the sensor first, and get pressure test, the cel stopped coming on but i didnt want to keep running the engine if the oil pressure is low. Could it simply be the sensor? And throwing an engine code?

Johnnyboiranger22 · Jun 10, 2018

Can i use the OBD1 CODE READER? Its 2.3 abd has a port on passenger side firewall.

flynnternet · Jun 10, 2018

Yes, the OP "sender" is just a switch with a resistor on the dash to pull the needle to the halfway point. (Thanks FoMoCo....)

My experience with the 2.3L:
When I got my '91 the clock read 150K. Ran nice, but sometimes the OP gauge would start bouncing toward low. No rocker arm rattling so I asummed there was some pressure. Put on a mechanical gauge and confirmed really low pressure.
Assumed a bad oil pump and pulled the engine to replace. Once we got it all apart I found the intake sump screen was full of little bitty rubber pieces. I assumed at the time they used to belong to the oil pan gasket as it was ragged on the inside. (But not leaking.)
These bits were really packed in there, probably spent 30 minutes scraping the lil' buggers out from under the shield that covers most of the screen. And lots of brake-clean from the top. Ended up with a large marble sized blob.
Don't know if the pump was really bad, (doubt it) as oil pan being already opened up, we installed the new pump.
100K later I still read about 54# at idle.
If you have one of those really-must-have flexible inspection cameras, you might be to take a peek via the oil pan plug. (Although I'm not sure of the distance between the pan and intake.)
YMMV....

tomw · Jun 11, 2018

Definitely worth checking with a 'real' gauge. Then you know, rather than 4,361 opinions from the WWW.
The pan gasket in the 90's was a known, to some, cause of a low oil pressure condition. The material fell apart, and sometimes would block the pump intake to the point of engine failure.
Some used coat-hanger wire, or similar, to reach in through the drain bung, and scrape the goo from the oil pump intake screen with decent success. The pump does not actually need the full area of the intake screen to have adequate flow, so just scraping off 'some' of the particles made the pump able to do its job once again w/o having to pull the engine to drop the oil pan.
If you are adventurous, you can remove the plug, drain the oil, remove the filter, and rotate the pump in the reverse direction while feeding solvent into the filter mount, which would tend to flush the gunk away from the pickup screen. It does not take much cleanup to make a significant difference.
tom

Johnnyboiranger22 · Jun 16, 2018

Hey guys providing an update, i switched oil pressure switch and it was still acting funny, however the truck drove perfectly, No engine codes was thrown(even though i waited a couple days for scanner lol) but only time oil pressure gauge would move is if i touched the gas or switch to reverse, I hope its not oil pump, im going to try the gauge, where can i get one? Can anyone attach a link and i will try cleaning in the oil pan.

tomw · Jun 17, 2018

Johnnie

nly time oil pressure gauge would move is if i touched the gas or switch to reverse,

The two items mentioned have nothing to do with the gauge. Bettanickel that you have an electrical problem with grounding or power that change when your engine moves.
The engine will rock slightly from side to side as throttle is applied in forward or reverse gears. Torque. As the engine moves, the wires flex to some degree. If your gauge fiddles when the engine is torqued, I'd bet on a bum wire or connection.
It may be a frayed wire, or a bad ground strap from the back of the head to the firewall. You have to look & inspect. I think I would follow the oil sender unit wire to see if it is damaged as a first step.
tom

Johnnyboiranger22 · Jun 17, 2018

tomw said:
Johnnienly time oil pressure gauge would move is if i touched the gas or switch to reverse,

The two items mentioned have nothing to do with the gauge. Bettanickel that you have an electrical problem with grounding or power that change when your engine moves.
The engine will rock slightly from side to side as throttle is applied in forward or reverse gears. Torque. As the engine moves, the wires flex to some degree. If your gauge fiddles when the engine is torqued, I'd bet on a bum wire or connection.
It may be a frayed wire, or a bad ground strap from the back of the head to the firewall. You have to look & inspect. I think I would follow the oil sender unit wire to see if it is damaged as a first step.
tom

Thanks tom! Check oil pressure with gauge and it was reading 24 psi, the truck runs fine but i just defiantly didnt want it to actaully be low pressure, i did a whole cylinderhead on this truck without knowing a thing on working on cars but now i know a little, im going to trace the wire.

Low oil pressure

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