Went to pepboys to get a new sending unit. guy couldnt find the part for my car but after some talking we got this one that looked similare to the one i had on there. I think i had the original sending unit because it was all metal, i notice the ones at pepboys were all plastic after the threads. anyway i try the new sending unit and my gauge doesnt work still. with my old sender, the gauge was very jumpy and never worked right. when i put this one in from pepboys it didnt move teh gauge at all. is it possible this is the wrong sending unit or is there something else that could cause the pressure gauge not to work?

also on my 3.1L, the sending unit that controls the gauge in the car is the one over the oil filter right?

 

Check your grounds or go to a different parts store and get the one thats for your car. Borg Warner is the brand! O'Reily if in your area would have it.

Check for a circuit at the sensor, maybe your dash gauge is shot

 

this is a borg warner. anyone here ever replace the sender w/ a borg wagner? u still happen to have the part numer? this one is s4087. the original sender seems a lot more heavy duty though, this one feels like it would break in a month.

 

Get a meter out and see what it's sending out, only way you will know if the old one was REALLY bad or not! Not that the dash part is the real problem.........

 

which pins do i test on the sending unit? doesnt it need to be plugged in to send out a signal though? is oil an insulator of electricity? my plug had some oil on it maybe thats causing it not to work?

 

Yes Oil is an oil an insulator of electricity. First check the plug by probing both pins one at a time thru a meter to ground and see if you have power. If so then connect it so you can see if the sensor will complete the cirucit to ground (not back to the gauge) If not then the sensor is bad. I think you will have to do it with the engine running. Any manual should have a circuit digram for you to follow

 

how would i probe the pins for power without the sensor being hooked up? theres 3 pins on the unit.

 

Take each pin on the connector using a probe light and connect one end to the pin and one end to the car to see which has power. Do it with the car running.

 

http://www.geocities.com/vtcamaro/Pi...rams/pg174.jpg


According to this they should ALL have power

 

Woops maybe not, only one should have power, Also tells you how many ohms the sensor should read at zero pressure.

 

can i apply power to the connector under the hood that plugs into the sending unit and see if it moves the gauge in the car? how much power should i use and what pins?

 

No you can't, the gauge is what supplies power to the sensor and then the sensor resists thus adjusting current positioning the needle on the dash.

I think Pep Boys sold you the sensor that is used with warning light instead of a guage.

The only way to be sure is to probe those wires with the KEY in the on position and see if any pins are powered when you ground them using a meter or a probe light.

 

When you ground those pins the gauge SHOULD PEG when you find the one supplying power.

 

ok i got the right sending unit. still not working at the gauge though. i took my whole gauge cluster out, anything i can test while it is out. where can the problem lie? the sender is good, and im pretty sure the gauge itself is good but i dont know how to test it. anyone got any ideas?

 

This sensor was a large sucker, right?

I would test at the sensor before testing at the dash wiring, though. Maybe someone with a 90-92 3.1 manual can step in and help you with the pinouts for the sensor itself. Did you apply any teflon tape to the threads? This was one Large sensor, right? My '86 has two sensors, one for the gauge, and one for the fuel pump bypass. In '87 they combined the two sensors into one, and yes, the sensor (or sensors) come out at the oil filter.

 

yeah it was a big sender, not the smaller ones. mines like a cylinder. anyway i already took the oil gauge out and tested it with some power. it moves like it should i think, nice and smooth, not all jumpy like i had seen it a few months ago. the gauge itself appears fine. the sending unit is fine. the problem has to be between the gauge and sending unit (duh lol). i dont know what else to check though.

 

fixed it, seems that my needle on the gauge wasnt on correctly. doh


btw what is a good oil pressure range? sitting in park its almost at 80, about 70-75 or so. when in drive and coming up to a stop it goes down to about 40ish. is this acceptable? is there such a thing as too much oil pressure?

 

Beats me; on a hot day, when I come to a stop, my oil pressure drops to zero. (I'm assuming it's because of excessive bearing clearance due to engine wear, though.) The gauge is an aftermarket mechanical (Summit 2 1/16"), so I know there's no miswiring or bad sensors or anything.