New aftermarket oil pressure gauge

[Pogophil]

’m at a loss - any assistance would be greatly appreciated.

I bought an aftermarket oil pressure sender and gauge for my 98 boxster. I was hoping to have an oil pressure gauge for my track days this year. Here are the pertinent facts:

installed the sender in the stock oil sender port, located on the passenger side of the engine, with an adapter, no issues. No thread tape used in the install.

That sender showed about 10 ohms of resistance between the threads and the top port when I tested it. When I ground the oil sender, it shows 0 ohms between the threads and the top port.

So I believe the sender is functional.

Attached a wire with a spade connector to the top of the sender, and sent the wire forward through the grommet in the firewall and into the cabin. The wire is able to send current from end to end.

So I believe the wiring is functional.

I connected the gauge to a car battery for power to test it, and it powered on. It lights up anyway, and the needle does a sweep and back to 0 at startup. I connected the sender wire to the gauge. It reads 0 before I start the engine. And after I start the engine - still 0. The gauge doesn’t move.

I tried to bench test the gauge by grounding the sender and getting it to move off 0 - no change, still 0.

I thought I had a faulty gauge, so I bought another one - same issues exactly.

Seems like it’s either a faulty sender, wiring, or gauge. And I initially thought gauge, but I’m not so sure after the second one.

Does anyone have any suggestions? Or could perhaps point me in the right direction?

Thanks in advance!