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Discussion Starter #1
Greetings all. I have a '65 GT that I'm nearing the end of a restoration on. Recently as I was starting to test all of the electrical systems I found that the oil pressure gauge is constantly at 80. Doesn't matter if it has power, no power, even completely removed from the dash. It's not "pegged" at 80 meaning absolutely zero movement, if I move the gauge around a bit I can see that the needle wanders a touch, but it always reverts back to the top. Any guess as to what could be causing this? Thanks in advance.
 

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The Alfa pressure senders tend to fail in many and peculiar ways.

As a simple test, you might try unplugging the wire from the sender. See where the needle points. Then ground the wire and see where it points.

If both conditions result in max-span readout, you probably have a bad gauge, or a broken or shorted wire. If one of the wire states results in low and the other state gives high, you probably have a bad sender.

Where are you located? I may have a new sender that was sent to me by mistake.
 

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Completly removed and disconnected? I would guess gauge? Wait for more input from ABB gang.
 

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Completly removed and disconnected? I would guess gauge? Wait for more input from ABB gang.
That’s the way I read it (Fully disconnected and de-energized and the needle is at 80).
If so, the gauge needs recalibration (adjust needle to zero if there are provisions to do so) and recheck against a calibrated standard. The gauge is essentially a volt meter with the variable input from the sender. If it reads 80 psi without any input, the needle is hung up on the internal coil or been shifted from its zero set point.
 

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Discussion Starter #5
Hi all. Yes, it reads at 80 even when the gauge is sitting on my dining room table, as it is right now. Strangely, I look back at the photos of the gauge from when I took the dash apart (6 years ago) and it was reading at 0 back then. So, evidently something happened over the last 6 years while in a box. Argh.
 

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Did it get banged around? Or exposed to a magnetic field?
 

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Hi all. Yes, it reads at 80 even when the gauge is sitting on my dining room table
Well, what does it read on the kitchen table? :D

I look back at the photos of the gauge from when I took the dash apart (6 years ago) and it was reading at 0 back then. So, evidently something happened over the last 6 years while in a box.
As others have written, this sure seems like a problem that is internal to the gauge - not something with the wiring or sender (*). I would just send it off to North Hollywood Speedometer or whomever is your favorite gauge rebuilder. There may be a way of getting inside it and figuring out the problem, but ...

How does the fuel level gauge look (Trich knows this, but the two are both in the same housing on a Sprint GT).

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*) As DPeterson3 alludes in post #2, matching sending units and gauges is a bit of an art on Alfas. When I first read Trich's problem description, my first thought was "late sending unit - early gauge". But if it misbehaves outside the car, then I guess not. Still, if you decide to send the gauge off to be serviced, there might be some benefit in including the sender as well.
 

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Discussion Starter #8
Fuel level looks accurate (completely empty) but I'll try manually moving the tank sensor up and down and see if the gauge adjusts accordingly.
 

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I recently battled the oil pressure sender/gauge on my 78 Alfetta. Veglia gauges. My memory has mostly dumped the data, but if I recall the gauge read high all the time. The first sender I got from OKP made it worse. The second - different part number - made it all good.

Point being, I don’t think the late Veglia reads zero with either high or zero ohms input. Early type? No idea. I’ve still got the first sender I received from OKP. Might be for the early gauges.
 
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