SUPERMAC

ok so i feel like a damn tard cause i cant figure this issue out. been working on cars and trucks for 15 years and this one little thing is getting the best of me.

heres the deal...

my truck is a 1991 4x4 pickup with a 3.0l v6 auto. ext. cab SR5.

ever since i got it the oil pressure gauge has been sitting at full high on the gauge (full right) not reading at all.


from what i can tell its caused by a bad pressure sensor.
so i go buy a stupid sensor to throw in. and im only finding this sensor. (the thing with the red on wire sticking out) sorry for the blurry pic my camera wanted to focus on the wrong area. my oil filter is sitting just to the right of the sensor. am i looking in the wrong area maybe??


and from what i can gather its suppose to use this sensor...



so i try to swap them out. but the wires are different and i cant figure out a good way to attach them other then a spad connecter or just wrapping the wire onto the end. tried both and neither way made a difference with my gauge.

so... any ideas? cant find any wires that are messed up and i doubt its the gauge itself, but i guess its possible.

Hadmatt54

The beauty of working on cars and it doesn't matter how long that you have been at it; when problems arise you always learn something new. I've been working on cars for 44 years and I keep learning new things, so learning is a plus!!!!!

I take it that when you turn the key off the oil pressure gauge goes back to low.
It's not easy to see in the picture, but I would say that you have an oil pressure switch (as in on/off) that is used with an idion light. Turn on the key oil light is lit (on) start engine oil light goes out (off).
An oil pressure gauge on the other hand uses an oil pressure sensor the new one in your picture. The sensor is a variable resistor that allows different values of current to flow to ground as the resistance changes due to changing oil pressure, thus allowing the pressure gauge to go up the scale.
Right now your pressure gauge is grounded out that is why it is at full scale. As far as the connector, it looks like someone cut the factory connector and crimped a female spade on. The factory connector will attach to a male spade like the switch has now, but the factory connector also has a slot cut in the bottom to connect to the new pressure sensor that you bought. I'm not sure if you can get these from the dealer ...you would probably need a part # and a diagram to find the correct one, or go to a junk yard find the proper connector with some wire and splice it (Solder & heat shrink) into your oil pressure gauge sensor wire and your problem should be solved. That is as long as being grounded all the time didn't hurt the gauge.

SUPERMAC

no oil light at all when the key is on. and no matter what the truck is doing (turned on or off) the gauge is always sitting in that position.

i looked up the pressure sensor i needed for the year and model and all that for my truck at the auto parts store. paid $40 for some stupid pressure sensor (pictured) and then realized that the sensor thats in the truck is a completely different one than its supposed to have. not sure why its different (kid before me probably put it in), but i swapped it out anyway and it made no difference. now im thinking the gauge itself must be bad. however, from my experience normally if a gauge goes bad it reads zero. not full pressure. so i dunno. i thnk im just going to buy an aftermarket electric oil gauge and hook that up instead. its easier.

Hadmatt54

Not sure what you looked up, but according to the Toyota part #s from Toyodiy .com your truck takes either an 83520-14023 (Denso) or 83520-55011 (Yazaki) oil pressure sender. If you go to RockAuto.com Standard Motor Producs part # PS186 is a replacement for either of these and a PS186 is exactly like the sender that you bought.

I wonder if your truck had gauges to begin with or did the prevoius owner put an SR5 cluster in it. Switching clusters is not plug and play the pin configuration in the connectors at the back of the cluster is not always the same, some wires generally have to be moved around. If that is not the problem then the gauge might be fried from being grounded. I'm not at my home computer where I can read a FSM, but if memory serves me correctly one of ther tests for the gauge is to complete the circuit to ground through a 3.4 watt bulb, not grounding the gauge directly.

I'll follow that up when I get home from work.