Oil Pressure Gauge through the ROOF!

[rundmc]

Hey all,

Recently been noticing my oil pressure gauge on the panel is through the roof. Doesn't move at all - just sits well past the 80 on the dial by a full inch, hitting the DMC logo around the middle of the C.

However, the engine temp seems to stay normal and the vehicle does not exhibit any other symptoms.

Help?

Thanks,
Mike

[Farrar]

Sounds like a bad oil pressure sender. I believe the old ones were known for this. All of the vendors now sell proper replacements. Might want to test with a mechanical gauge first, though.

Farrar

[content22207]

You just lost the connection between the sender and the gauge cluster, that's all. The oil pressure gauge pegs straight up without the sender (I'm pretty sure coolant temp does the same). Most likely culprit is a broken terminal on the wire at the sender.

Bill Robertson
#5939

[stevedmc]

The oil pressure sender is located to the left of the oil filter. You should have one wire running directly to it. You can test your gauge by simply connecting the wire to any grounded part of the car such as your engine.

Now would be a good time to replace it with a PS133 oil pressure sender from Autozone. It cross references with a 1975 Corvette and has a lifetime warranty for just $15.

[content22207]

Only ground the gauge for a brief amount of time. Most analog gauges are driven by a fine wire wrapped around the needle. Directly shorting them will melt the wire if left that way too long.

Bill Robertson
#5939

[Ryan King]

My Oil Sender bounces all around, but mostly stays about the 80 line. I have a recently replaced sender in mine. Maybe I can get a brief film of it and post it here.

[GS450-Junkie]

I wouldn't trust any of my guages on these cars. They're just kind of there for filler. Learn to not look at them much...they all lie. 8)

[Mike C.]

I made a post a few weeks back about my flaky oil pressure readings bobbing all over the place. I ordered Marty Maier's sending unit and installed it yesterday after my oil change.

I had also found Farrar's videos on Youtube about his oil pressure readings on his car:

Cold:

http://www.youtube.com/watch?v=4AnUWcuGsVk

Warm:

http://www.youtube.com/watch?v=8bBLPkIYTeQ&feature=related



The issue I had before was during the cooler months when I would actually drive the car, the temp never rose to even the level of that first mark on the temp gauge. I would CONSTANTLY have an oil pressure in the 70/80 range, which barely ever changed.

For the first time, I decided to drive in the hottest part of a humid day (approx. 92 degrees) for over an hour and a half, in stop and go traffic. My readings were not that far off from Farrar's videos. My idle oil pressure was slightly higher. When driving at the point of fan cycling, slightly higher temp than what is showing in video 2, I was showing a driving pressure between 70 and 40 (guesstimating around 65 to 50).

The benefits of the new sending unit is my gauge doesn't flutter nearly as much as it used to. Since I haven't driven that much, I don't really know a downside yet.

I love project like these that hopefully allow a close to a reliable reading for a car.

[content22207]

... I had also found Farrar's videos on Youtube....

Farrar's car sure does idle smoothly.

Bill Robertson
#5939

[jmettee]

If you go to 1:14 on my video, you can see what my original oil pressure sender does with my gauge. This is normal for my car. When cold, it just sits on 80.


http://www.youtube.com/watch?v=S_7rzp44gqU

[jmettee]

Farrar's car sure does idle smoothly.

Bill Robertson
#5939

so does mine :) :devil:

[orbitron3000]

I have kind of a similar problem, and I am curious to know if it the oil sender unit or a different problem. I noticed today that whenever I would step on the gas, the oil gauge would start to climb. Firstly, what is the nominal oil pressure? And secondly, would a faulty oil sender unit cause this sort of behavior?

Ryan
#5780

[Farrar]

Oil pressure normally varies with engine speed.

Farrar

[DeLorean03]

Farrar, you get your headlight problem fixed? I had the exact same identical problem - my headlight had bit the dust.

[Farrar]

Farrar, you get your headlight problem fixed? I had the exact same identical problem - my headlight had bit the dust.

Yes -- I had forgotten that the low-beam lights are dual-filament bulbs. (Insert Homer-like "doh" here.) The lower filament had burnt out. All I had to do was replace the bulb. I felt pretty silly after discovering that one. :lol:

Farrar

[DeLorean03]

No biggie! Just wanted to let you know just in case! Good deal!

[BobLS]

The oil pressure sender is located to the left of the oil filter. You should have one wire running directly to it. You can test your gauge by simply connecting the wire to any grounded part of the car such as your engine.

Now would be a good time to replace it with a PS133 oil pressure sender from Autozone. It cross references with a 1975 Corvette and has a lifetime warranty for just $15.

"You can test your gauge by simply connecting the wire to any grounded part of the car such as your engine."

And what should the test reveal?

[David T]

To test the wiring to the gauge and the gauge you disconnect the wire at the sender and the gauge should be at or near zero. When you touch it to ground the gauge should go all the way up. Most likely you need to replace the sender, the original ones were never calibrated right.