I have a 95 camaro z28 and my oil pressure gauge goes to the top at 80 at startup and then back to 20 at a hot start, i've even seen it do it before i started the car. Should i replace the sending unit or is it the oil pressure switch that i need to replace?? Any advice would be appreciated.

 

There's only one piece in the system - the oil pressure sensor:

http://shbox.com/1/op_sensor.jpg

Could be an intermittent loose wire or a faulty sensor. When the circuit is "open" the gauge pegs at max reading.

 

Cheapest place to buy the sending unit??

 

Rockauto.com has decent prices on parts if you don't need it right away...otherwise go to your local Autozone/Advance Auto...

 

Does this also control the fuel pump??

 

Huh? How would the oil pressure gauge/sensor control the fuel pump? They are entirely different systems. The fuel pump has its own relay and circuit.

 

I thought one end of the oil pressure sending unit had something to do with the fuel pump??

 

On some vehicles, the fuel pump power source/relay is interlocked with a switch in the oil pressure sensor, to shut the fuel pump down on loss of oil pressure. I think the Corvettes may be wired that way. But the F-Bodys do not interlock the fuel pump with an oil pressure switch.

 

Since the gauge is behind in the intake, how much of a pita is it going to be to replace it? How long should it take my mechanic??

 

I've got bigger issues now. I got the car out and the pressure was way low, almost down to the red as I drove my car to my mechanics. I had him change the sending unit and I drove back home and went inside for about 15 mins came back to start the car and it started, the oil pressure was in the red and my check gauges light was on. I shut the car off, started it back up and the gauge was at 15lbs. I drove it around some and the gauge was still just above the red line. I put some Rislone motor treatment in the engine about a week ago to try to quiet a noisy lifter that I have, could that have anything to do with it? Also, when I bought my sending unit at O'reilly's it looked as if it had dirt on the box and it was smeared, could i have accidentally gotten a bad sending unit? My mechanic won't be able to look at it until next week, so i'm hopin that the car will start next week when i attempt to go to my mechanics with it, but i'm scared if i dont have the oil pressure i'll torch the motor. I bought a mechanical gauge tonight, so when i go see my mechanic he can put that on, does anybody have any ideas for me besides the mechanical gauge and changin the sending unit again? Also btw, when i drove it home, I would get on the gas and get it up around 2k rpm and the gauge would not move, it seemed like it was almost stuck on about 22lbs of pressure, this car only has 102k on it and i really dont think the pump is bad. Any ideas would be appreciated.

 

Did you mechanic test the continuity of the wire to the sensor?

 

nope, How would he do that? Is it hard to do?

 

Thanks for the reply injuneer, can this thread be moved to lt1 engine tech by chance, i'm hoping i can get more opinions there, hopefully? I think i may go ahead and change my oil, since i put that rislone in, i'm wondering if my oil filter is clogged? I changed the oil 800 miles ago, but added the rislone about 150 miles ago and ever since, the gauge has been messing up. I used Valvoline syn 10w30 and a K&n filter, could it be clogged? What oil and filter should i go with this time, I'd like to use Valvoline or Mobil 1, but i'm unsure on the filter to use, ac/delco vrs. wix vrs k&n vrs Moroso racing filter vrs Mobil 1 filter?? Lol Any thoughts would be appreciated.

 

If your mechanic doesn't know how to do that, get a new mechanic

Moving to LT1 Engine Tech.......

 

Do you have to pull the dash cluster to check for the continuity at the wire?