I have an 89 lx with a sc 5.0, when its idling or going slow threw town the oil press reads right in the middle on the fact gage ,but going down the highway it will drop 1-2 notches ,witch is 1 notch above
nothing
Also its NOT knocking
Just like StangGT1995 stated get a real guage on it, what you are typing really means nothing. the factory gauge is known for being inaccurate, you could have a ground problem, failing sendor or real issue. you need real #'s to know what is going on. normal is about 20psi hot idle and 40-60 psi @ 2,000 rpms is good. keep us posted on what you find.
the funny thing is,, rev it up and oil press goes down , and all the other electrical stuff works great, I would think a bad ground would efect other things too
the funny thing is,, rev it up and oil press goes down , and all the other electrical stuff works great, I would think a bad ground would efect other things too
not always same thing happens with the stock water temp gauge, it's also a known problem and that is one of the fixes. stop guessing and put a gauge on it, even a temporary one to get a reading. you could have a minor issue related to the stock gauge or a bigger issue like the oil pump, pickup, etc that needs your attention.
Your next question is how to install a mechanical oil pressure gauge. With that in mind, here's some tips...
Mechanical oil pressure gauge installation..
1.) Remove old pressure sender. It is located down by the oil filter and has 1 wire on a push on screw connector.
2.) Install ¼” pipe tee fitting with a short ¼” nipple on the place where you removed the oil pressure sender.
3.) Install the original oil pressure sender back in one of the tee ports.
4.) Install the gauge line restrictor in the remaining port of the tee.
5.) Connect the flex tubing or hydraulic hose to the gauge restrictor. Be sure to route the tubing or hose away from the exhaust manifolds. Be sure to either use hydraulic hose or oil and heat resistant flex tubing for the pressure line. Do not use copper tubing for the connection to the gauge restrictor or engine. Over a period of time, the vibration will work harden the tubing and cause it to crack and fail.
6.) If the gauge is going to mount under the hood, connect it to the end of the hose or flex tubing. Use some Tie-wraps to secure the gauge and its plumbing to the wiring harness on the driver’s side inner fender.
7.) If the gauge is going to mount in the passenger compartment you get to find a place to run the tubing through the firewall. I suggest that you pick your spot from the inside since that is the area with the most difficult access. Do not run the tubing through the exact same hole as the steering shaft. It will tangle up with the steering shaft and cause major problems.
8.) Install the gauge inside the car in the location of your choosing. Connect the pressure line to the gauge and secure it out of the way of moving parts with Tie-wraps.
9.) Be sure to ground the gauge lighting wire to clean, shiny bare metal. Connect the other wire from the gauge lighting to a light blue/red wire on the radio wiring harness. There are 2 connectors in the radio wiring harness, but only one of them has the light blue/red wire you need for gauge illumination. Solder the gauge lighting wire to the light blue/red wire on the radio harness and cover the soldered joint with heat shrink.
Be sure to use a gauge restrictor fitting in the pressure line going to the gauge. The restrictor will prevent all of the engine's oil supply from ending up on the pavement before you can stop it if the gauge line fails. I had a gauge line rupture, and the restrictor fitting saved my engine from serious damage.
I think it was a bad stock gauge, Becouse I have a a hand held manual oil pressure gauge that I screwed in where the stock oil sending unit is, and it acted ok