Okay, my new oil pressure gauge that I just wired up does something weird. When I turn ignition on it shoots all the way past the max reading (80 PSI). I can unplug the sensor wire from either the gauge or sensor side and the gauge stays pegged. If I unplug the ground on the gauge it drops to zero, and doesn't do anything when the engine's turned on (sensor plugged in). You would think it's hard to screw up such simple wiring, but I seem to have managed.
VDO gauge experts, the power lead comes from the fuse terminal to the + terminal on the gauge. The sensor wire is plugged into the 'S' terminal on the gauge. The ground is plugged in on the bottom terminal, which I'm assuming is the ground. That's what the diagram says, anyways. I'm using 16 gauge wire all around. Any help?
Mark D.

You have to have the sensor and ground mixed up (on the guage). Try switching the leads to those two terminals.

To test a guage, you ground the sensor wire with voltage applied to the + terminal and the guage swings full.

or

The guage is bad internally.

I think I have a couple of guages if you want to try another.

Okay, I switched the terminals and it's just dead..... 'course, I don't know how good the sensor that' in there is. I bought a dual sender from Pelican, but it doesn't fit in the hole in the sheet metal, so I'll have to make it fit somehow. I'll get back to you on this. If it still doesn't work with the new sensor, I'll borrow one of your gauges. Thanks.
Mark D.

With the terminals switched or back the way they were and the power on .... ground the oil pressure lead on the engine ..... if the guage swings full reading, the sender is bad.

Oh, BTW, if you are using the stock sender - it will open the circuit as it is not really a variable resistance unit .... it's more or less on and off ... with no or less than 6 psig(?) oil pressure it closes and turns on the idiot light. With oil pressure it opens and the circuit is incomplete. Won't work with a guage.

Okay, I was wondering about that. I figured that it worked the same as the dual sender because I thought both the terminals on the dual sender were the same, but I just went out and looked and there's a "G" and a "WK" terminal on the sender. I'm guessing "G" means gauge. There's no instruction on that on the box.
Also, I just went out and tested it like you said and it's result is opposite. With the wires switched, it's just flat no matter what I do. With them hooked up according to the instructions, it swings full, BUT if I ground the sensor wire to the engine it falls back to zero. I'm going to have to get that new sensor in, and then I'll see what it does. Thanks for the help.
Mark D.

Any ideas on how to get that sensor to clear the tin and the dizzy?
Mark D.

Okay...so you've got the 2-pole sender. It needs to be grounded to work or the gauge will do what yours is doing and peg as soon as it is powered. Either ground the case of the sender to the engine, etc. with a separate lead, or trim your tin to accommodate it. If the sender is screwed intp the engine, it is already grounded.

You can also get a hose to locate it remotely.

you need a relocation hose from aircooled.net

its a 12" piece of hose that relocates the dual sender.
let me find a pic
you can barely see the dual sender laying on top of the fan shroud.

Found it... Do I want the 1/8-27 or the 10 X 1 fitting? 10 X 1, right?
Mark D.

You want 1/8" NPT. That's what the case is, as well as the extension hose. You DO NOT want any thread that's not tapered. You use NO gasket or sealing ring. Ground the body of the sender, use 12V + for the "+" on the gauge, ground for the "-" on the gauge, and the wire from the "G" terminal on the sender for the "S" terminal on the gauge. "WK" is for the lamp.

The Cap'n