Oil pressure sender

Topic: Oil pressure sender (Read 1489 times) previous topic - next topic

Oil pressure sender

October 20, 2012, 12:11:47 AM

I have a full digital dash and I think the oil pressure sender is going out or perhaps I have a bad ground. Since I've owned the car the gauge has displayed 5 bars when the engine is running no matter what (I know it's a dummy gauge). Now it will display 4 or 5 bars for no apparent reason. It will even bounce back and forth between 4 and 5 bars while the engine is running. It doesn't matter if the engine is at idle, under load accelerating, or cruising at a steady pace. The sender is still working but perhaps it is slowly dying or has a dirty connection? Oil level and pressure are fine. Even if the oil pressure was changing while driving the gauge is a dummy so it can't actually move (unless it drops dangerously low) hence I know it's some kind of electrical problem.

If the sender is dying does anyone know if this sender http://www.latemodelrestoration.com/item/SW1547B/1979-89-Mustang-Oil-Pressure-Sending-Unit along with this http://www.latemodelrestoration.com/item/LRS-9278A/1979-89-Mustang-Oil-Pressure-Sending-Unit-Extension-50L will give me a functioning gauge? I know I would have to remove the resistor inline with the gauge wiring but, even after searching, I can't find the part number for the sender that makes the gauge function like a real gauge.

Oil pressure sender

Reply #1 – October 22, 2012, 11:11:23 AM

mine does the same thing,, look for your car to soon beep at you with the display changing to altert you of low oil and then suddenly going back to 4 or 5 bars.
look for this symptom to go away and return for no reason at all.

sorry, no help here.

i will be changing my oil with engine flush soon just to see if the float is py with debris and maybe there is too much "weight" on the float in certain viscosity conditions the oil experinces during running.

Oil pressure sender

Reply #2 – October 22, 2012, 10:48:25 PM

Quote from: jcassity;400974

mine does the same thing,, look for your car to soon beep at you with the display changing to altert you of low oil and then suddenly going back to 4 or 5 bars. look for this symptom to go away and return for no reason at all.

My car also does exactly what jcassity describes. It is very intermittent and doesn't seem to follow any rhyme or reason. I have no clue what causes it, but I hope you find a solution!

Oil pressure sender

Reply #3 – October 25, 2012, 10:26:32 AM

I'm going to replace the sender with one that makes the gauge "work/move" like a real gauge and remove the resistor from the line so it will actually work. It's going to be a winter project since I'm putting the car away in a few weeks for the winter. I might wait till the spring so I can actually test it though. My guess is that the contact/float in the sender or the inline resistor are just old/dirty and need to be replaced. The circuit is more than likely not supplying the correct voltage to the gauge, hence its movement. It used to always stay right at five bars instead of bouncing between four and five. At least it's not beeping at me for no reason yet.

Oil pressure sender

Reply #4 – November 05, 2012, 12:41:28 PM

Just an FYI: I "fixed" this by cleaning the inside of the sender connector and the terminal on the sender. I then put a little dielectric grease on the sender terminal and plugged the sender wire back in. It's been working fine since I did this.

Oil pressure sender

Reply #5 – November 05, 2012, 02:39:45 PM

On my old 87, I decided it probably had to do with either the alt or the irv in the dash. I could make it go from 5 to 4 bars by turning on the lights, heater, rear defrost, ect. Whenn it started beeping, I just grounded out the guage, after the one I could get locally didn't help.