So after trying different brands and combinations and ending up with a gauge reading the max as soon as it gets power, I ended up buying an oil sender and a Gauge from Autometer to match.
Nothing happens when I turn ignition on, and then when I crank and it starts : It goes to the max again !
Ground seems good as my Tach is hooked up to this same spot and it works.
I was wondering if an engine not being grounded to the frame could cause this issue? Because I’m not sure if it is… I’d have to look at it.
I’ve changed sensors three times but I’m starting to believe they’re all junk
But i’m getting frustrated and thinking about using a mechanical gauge maybe mounted on the hood or something.
It’s possible that the lack of ground between engine and chassis may be at fault; at any rate, please add that grounding strap, as it is extremely important for all of your electrical systems.
The other cause may be a pinched wire between the gauge and sending unit, grounding the oil pressure line.
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I agree - most likely the wire to the oil pressure sensor is shorting to ground somewhere along the way. You can verify this by pulling the wire off the sensor. If it still maxes out the gauge, it’s either a shorted wire or possibly a shorted gauge post at the instrument cluster. If not, it’s probably a bad sensor.
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Yeah it goes back down when i remove the wire from the sensor… i’m really upset, it’s the third one i’m buying !
Going to mechanical next time…
What resistance do you measure across the sender with the wire disconnected at both ends do you have continuity to ground? What are the resistance specifications of the gauge? Does the sender match? Do you have a schematic showing how the gauge is to be wired? No way to diagnose electrical problems by looking at it
I get no reading at all when measuring resistance between the body of the sender and the signal stud; No reading between the signal post on the gauge and the sender… I get about 85 ohms betwen the + lead and the Signal post on the gauge. When grounding the signal wire it maxes out so i guess the gauge works.
I would say the sender is (yet again) bad.
When you say no reading, is the meter indicating 0 ohms or open (infinite ohms)? And is that with engine running or off?
It doesn’t read 0 ohms, the screen goes blank which I interpret as infinite resistance ?
It’s with engine off
I am asking you to check the sender not the gauge. We need to know what the sender is doing
Yeah, and sender reads infinite resistance. (screen goes blank)
What does sender measure with car running?
I didn’t have the time to check it, I had to go.
However I did start the engine and the gauge maxed out.
I’m guessing resistance should be close to Zero at that point… I’ll try tomorrow.
Right now I feel like it’s acting like a weird switch telling me there is oil pressure by going to the max… I don’t know…
Thats what we need to know in order to determine the sender is bad rather than something else. But it definitely is looking that way!
Sounds like the sender might be mounted with Teflon tape and not making contact with the manifold (ground).
Need to measure resistance from the sender base to the manifold.
Or the sender is a switch type and not a gauge type. Typically they work as a closed switch making a ground for the oil light when there is no pressure and then they open up with about 5 PSI. However there are some that do exactly the opposite. This is why it is important to know the specs for the gauge.
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I can say two things for sure :
1- it is a gauge type sender, the one that looks like a bell. From autometer
2- I did put teflon tape to install it.
I might try reinstalling it without it
Take the resistance measurements first, then we will know what needs fixed. Pretty safe bet you are making ground contact with the sensor since it is pegging the gauge. Usually, the teflon tape flows into the valleys leaving adequate electrical contact on the thread peaks - unless they got carried away and layered on way too much.