I have a 1987 Wrangler with oil pressure gauge pegging when you turn the key to on. Problem I'm having is that the Oil switch is soooo close to the motor mounts that there's no room for a longer switch. The one I pulled out looks like a Duralast PS101. But since I just got this as a project jeep I dont know if the one that in it is the OEM switch. Guess If I knew if OEM was Normally open or closed would help me to know if the Duralast would work
Is the oil pressure switch normally open or closed?
- Thread starter Don329
- Start date
I also posted a question concerning the Oil Pressure SWITCH, different than the Oil Pressure SENSOR (Sender) that sends info to the Oil Pressure Gauge. My 1990 YJ has no Oil Pressure light on the panel, so I really don't know WHAT that switch does for the Jeep! In my case, the connector fell off the Oil Pressure SWITCH with no indication or operational effect. However...
On my 1990 YJ with a 4.2 6 Cylinder, the Oil Pressure AND Switch screw into a common block that itself is screwed into the engine block. There is no issue with proximity to the engine mount (See Photo).
I changed the Oil Pressure Sensor and it did not fix the same issue you have, that being high pressure indication (full needle deflection). I also connected (and disconnected) the oil pressure switch with NO effect on the oil pressure gauge.
My next step will be to measure two things... 1.) Check the resistance of the Oil Pressure Sensor (Sender). The gauge calibration is: 0 psi, 1 ohm, 40 psi, 46 ohms, and 80 psi, 90 ohms. This will verify the sender internal variable resistance,, and 2.) Measure the Oil pressure Sensor (Sender) voltage at the connector. Should be about 7.5 vDC. If not, the printed circuit board or the gauge is the problem. If you have 7.5 vDC, , replace the Oil Pressure Sensor (Sender).
I just shotgunned my issue and replaced the Sensor (Sender) without testing anything. It did NOT fix my high oil pressure indication problem.
Now, the Jeep XJ and MJ both have an oil pressure light and switch, so I don't understand why my YJ has the switch and connector installed. But to address your question is the following from the 1990 Service Manual, XJ & MJ section:
Oil Pressure Indicator (Light)
Voltage is applied to one side of the indicator BULB and the Oil Pressure Switch is connected to the other side. When Oil Pressure is too low, the switch closes providing a path to ground, and the indicator lights.
On my 1990 YJ with a 4.2 6 Cylinder, the Oil Pressure AND Switch screw into a common block that itself is screwed into the engine block. There is no issue with proximity to the engine mount (See Photo).
I changed the Oil Pressure Sensor and it did not fix the same issue you have, that being high pressure indication (full needle deflection). I also connected (and disconnected) the oil pressure switch with NO effect on the oil pressure gauge.
My next step will be to measure two things... 1.) Check the resistance of the Oil Pressure Sensor (Sender). The gauge calibration is: 0 psi, 1 ohm, 40 psi, 46 ohms, and 80 psi, 90 ohms. This will verify the sender internal variable resistance,, and 2.) Measure the Oil pressure Sensor (Sender) voltage at the connector. Should be about 7.5 vDC. If not, the printed circuit board or the gauge is the problem. If you have 7.5 vDC, , replace the Oil Pressure Sensor (Sender).
I just shotgunned my issue and replaced the Sensor (Sender) without testing anything. It did NOT fix my high oil pressure indication problem.
Now, the Jeep XJ and MJ both have an oil pressure light and switch, so I don't understand why my YJ has the switch and connector installed. But to address your question is the following from the 1990 Service Manual, XJ & MJ section:
Oil Pressure Indicator (Light)
Voltage is applied to one side of the indicator BULB and the Oil Pressure Switch is connected to the other side. When Oil Pressure is too low, the switch closes providing a path to ground, and the indicator lights.
Gilaguy23
YJ Addict
In the same case on my 91 there was no problem with the sending unit, its all in bad grounds at the gauge cluster. Pull it, take it apart, clean all the little contact points and I tapped another ground to the existing cluster ground and everything started working again. I will say the factory gauge does read about 15 psi under what my after market one does. Cant say out of the 4 cj's, 2 YJ's and a TJ the gauges were with a poo far as accuracy if they even worked at all.
I agree with Gilaguy... the gauge accuracy on these old YJ's is questionable. I do find that the Voltmeter, though, agrees with a handheld voltmeter. However, I do value the bragging rights that all my gauges are original and they all work. I will drop the gauge cluster and clean up the grounds and contacts to improve the situation.
In the summer when I have the doors and top off, I get at least 1 offer per week to buy my YJ or someone wants to talk about a Jeep in their history. I always brag... 1990 Jeep, 410,000 miles, every gauge, switch, lever and button works as intended. It is far more cost effective to maintain the heck out of ANY vehicle than to buy new. And I'm finding a LOT of interest in my old Jeep and 1998 GMC pickup K3500 Crew Cab, to the point I worry about vehicle theft.
In the summer when I have the doors and top off, I get at least 1 offer per week to buy my YJ or someone wants to talk about a Jeep in their history. I always brag... 1990 Jeep, 410,000 miles, every gauge, switch, lever and button works as intended. It is far more cost effective to maintain the heck out of ANY vehicle than to buy new. And I'm finding a LOT of interest in my old Jeep and 1998 GMC pickup K3500 Crew Cab, to the point I worry about vehicle theft.
rrjank
New Member
I am trying to replace this guy, photo below. It is listed as an Oil pressure switch. In my 2.5l 4 cyl. 1995 it sets in front of the distributor cap, to the left of plug #1 behind where the AC platform is. It sits straight up and down and is easy to get to, but I cannot get a socket deep enough to capture the base of the sensor where the nut is. I took the new part into the store and find that 1-1/16th or 27 mm both work. Neither was deep enough, close but not enough. I tried a open wrench but the angle nor clearance are not there. I could force it out with vice grips, then hand tighten the new one, but that feels wrong. long story for a short question....where did you get your sensor socket? Do you have a link?
Flyer58
YJ Enthusiast
rrjank
New Member
They literally make a socket for that. Might want to find a new parts store...
https://www.amazon.com/Lisle-13250-Pressure-Switch-Socket/dp/B0002SR2RY/?tag=yjforum-20
https://www.amazon.com/Lisle-13250-Pressure-Switch-Socket/dp/B0002SR2RY/?tag=yjforum-20
