So I havn't driven my Z for a few weeks and it was running fine last time I drove it. So today I take it out for one last hurrah and I'm always mindful of my oil pressure, and I just happen to notice that no matter what, my oil gauage is always reading 20 psi. Idle, off idle, 2K, 3.5K it didn't matter, it always sat right at 20psi. I didn't hear any unusal noises are anything, but I also didn't get on it at all as soon as I noticed it.

So is it possible my pressure sender is going batty, or is somehting more serious like my main bearings or the oil pump?

 

there is a chance its the oil pressure sensor, I would replace that first.

 

I have a 383 solid roller FS if your looking for a new motor

 

How difficult is it to replace the sender? I've done the intake manifold seal fix twice and installed my hot cam kit myself.

 

If it's the oil pressure sensor you'd like to replace, it's very easy -WITH THE RIGHT TOOLS.
If it's the sender you're looking to pull, I can't help you. I don't know what or where the oil sender might be.

I wrote this up on a different forum, but thought it informative enough to copy/paste here;

I just did this with my car this morning too.

I found that pulling the EGR valve off helped considerably, and I would NOT advise even attempting this without the needed 1 and 1/16th inch, 4 inch deep well specialty socket.

My story went like this: I read that oil pressure should vary with RPM and started to get worried. My oil pressure was pretty much pegging at 55 and varying maybe 5%, so I just had to get this fixed ASAP -despite the fact that I have driven the car this way since I bought it 6 months ago.

So on dinner break Wednesday, I hit Auto Zone and buy the replacement sensor. I had unhooked the wire to the sensor so I had a rough idea what the replacement sensor plug recepticle should look like. Auto Zone looked up the part number, and told me there were 2 different parts, grounded and ungrounded. He brought one of each out, and one was about 1.5 inches long, and looked similar to a grounded male 120 volt plug -it had 3 prong plug ends coming out of it, so I knew that was NOT the one I needed, and bought the other one.

The guy at Auto Zone spent some time looking for a Oil Pressure Sensor Switch socket, saying he could hae sworn I would need one, but he couldn't find one or the information about it anywhere.

He added when he swapped out his, his just used an adjustable cresent wrench.

I headed home after work to get this swap done.

I learned that most cresent wrenches only open to 1". I need 1 and 1/16" and couldn't get it. I tried multiple pairs of pliers, and when I finally found a pair that was short handled enough to be able to turn in that location, I promptly used it to (accidentally) twist the plastic half right off of the Oil pressure sensor switch.

Oops. In for a dime in for a dollar I figured, and began thinking about what I might be able to find open that might have a tool or 2. Walmart was the only thing open, and I ended up buying a $9, widemouth adjustable cresent wrench that was capable of opening up to a whopping 1 and 1/8.

Thinking I was in luck, my new "handiest tool ever" and I headed home to finish this job. 30 minutes later I decided that I couldn't get the right angle on what was left of the sensor to use the cresent wrench and pulled the EGR valve off so I could hit the sensor at the correct angle (read: none).

It only took me a couple of grand pulls to know it was going to come out this way. I closed the hood and went inside for the night. I spent some time rereading everything I had been looking at and knew the socket would be the answer.

Morning came and that meant I was without the second car (wife went to work). So I lugged my 4 year old the 2 miles to Napa and back on foot to get the magic socket.

Socket in hand, and still pissed about the whole situation (me, being an idiot), I actually left Napa feeling the $10 I spent on the socket that I would probably never use again, was a damn fair trade. I knew this socket would work.

I pop the hood, put the socket onto a 3 inch extension and ratchet, and 30 seconds later I have the old sensor off.

I grab the new sensor and attempt to thread it in. It won't go. I try again. It won't go. Doesn't seem to matter what angle I hit this mating at, I can't get the two lined up.

I look at the old sensor. It somehow seems different. I compare. Sure enough the new one has (guesstimated) 1/2 inch stem diameter, and the old one was (guesstimate) 3/8 inch.

I had assumed when I bought the replacement that by not taking the sensor that obviously didn't mate up, that I had the one I needed. I didn't.

The wife came home from work, I ran back to Auto Zone for the REAL replacement, part number OP24501.

Once I had the part in hand and was back at home, I had the job finished up within minutes. In fact, if I had to estimate, I'd say that once I had the right tools and parts, I had *maybe* 10 minutes into this swap. Total time with all the screwing around, however ran well into the 2 hour mark.

So, why the long post? Just trying to let my idiocrity become your stepping stone to perfection.

The kicker that made the whole story. After getting the new one in a saw NO immediate change (the first day) to the displayed oil pressure reading, still 55, +/- 5%.

So, in summary -you'll need the replacement part (for my 94 formula it was OP24501 -and NEITHER parts in the AutoZone computer system were correct). You'll also need a 1 and 1/16th inch deep well socket, and some thread sealant, (I used teflon tape).

 

easy its right next to the oil filter about a inch up just unthread and unplug like a o2 sensor

 

Only 93s have the oil pressure sensor right above the oil filter...94 and up they are ont he back of the intake manifold. Make sure to buy the special socket for it (I paid $7 for the socket myself) and socket extensions and a swive attachment will be your friend. If you have all that it's not too difficult really. Like the guy above said, when i had to get a new one BOTH the parts in the pep boys computer i was at were wrong - i highly suggest you take off the old one first and bring it with you. They may LOOK the same but they had 3 units all with different thread sizes.

 

Assuming the reading is correct and I'm only seeing 20psi, do you think I already have some engine damage?

 

wronng 95-97 is on the intake 93-94 is by the oil filter i have a 94

no you would not have damage from running only 20 psi even if its correct

 

My 94 is on the back of hte intake. Also the 94 T/A i just sold was on the back of the intake. I win!

seriously though, perhaps this changed in the middle of the '94 model year?


To answer the posters question - assuming you really ARE getting only 20psi even at full throttle then you have a problem. Is the engine idling rough at all (perhaps a cam bearing spun etc.?)? Have you checked your oil level at all?

 

cam brgs dont usually spin i have only seen one motor that has done this in 15 yrs of my family owning a machine shop and we do about 18k motors a year.

20psi while its low would not hurt a motor till it hit 10 psi or lower at above 4200rpm

mine is a 94 ta gt so maybe they did mine there. but also my location is more accurate as its the best pickup place for oil pressure

 

mine was a red '94 GT as well. But yah next to the oil filter is a more accurate location, got an aftermarket one hooked up there. I had the front cam bearing slowly wear down on my Lt-1 before having to rebuild. Pressure kept dropping to lower and lower levels every time i drove it, over a 4 week period i went form having a good 50-60psi at WOT to only about 12 psi (and run about 6psi at idle)...seemed like every day it would give me about 2-3 psi less, finally had ot tear it apart and rebuild itJust my .02. But if your car is at 20psi ALWAYS no matter your throttle position i would say it's the sensor. Even if you had internal engine problems causing your oil pressure to be low you wouldn't get 20psi at idle and WOT all the time, it would vary even if just by 5psi or so.

 

Oil pressure is rpm sensitive not load sensitive so I don't quite understand pressure at idle vs. wot. At any rate with a steady pressure like that and as I stated pressure being rpm sesnitive my bet goes to the sender or gauge.