Oil Pressure Gauge Pegged

[ramluk]

Hey folks,

I'm working on restoring my factory gauge cluster (Had some aftermarket gauges from AutoZone, factory didn't work) and I can't seem to get my oil pressure gauge working. It's a 1985 k10 but with an 010 block. I bought and installed a oil pressure sending unit drivers side by the dist cap, and I have the boot wire that's tan but my gauge is pegged out. The wire in engine bay reads 12 volts with ignition on, but even when I ground the wire it's still pegged out.

So far I've replaced the circuit board, and the gauge. I'm suspecting the wiring at this point but just seems odd I'm getting 12 volts. Not a real knowledgeable guy when it comes to electric. My battery gauge works fine and I have the turn bulbs and backlights working. Seems like maybe it needs to be grounded, but you would think if I tried to ground it on the boot in the engine bay that it wouldn't stay pegged out.

Appreciate any help/troubleshooting tips!

 

[Jgonick]

If you used teflon tape on the sender- it might not be grounding. What happens if you ground the tan wire to a known good ground &/or where did you try to ground it before?

Check this video out. It explains how it works and how to figure out what is wrong.
Oil Pressure diag-LINK

 

[ramluk]

When I ground the tan wire it stays pegged out.

I watched that video and cut me a piece of wire and did just like the guy in the video did, grounded it to my ground terminal on the battery. It pegged out again, but actually smoked and burnt up my circuit board a bit.

I originally plugged it into the spade in the boot and it stayed pegged. Then I wrapped it around a bit of wire that was exposed behind the boot and it burnt up a bit.

 

[Jgonick]

Sorry to hear about your circuit board. Did you possibly ground the sender wire to the wrong terminal of the battery or left the power on for more than a few seconds when it was grounded?
You said you have already replaced the circuit board and gauge. It sure is acting like a bad gauge to me.
However, that looks like quite a bit of exposed wire behind the connector.
?Maybe a bad wire or connection that is causing higher resistance? -That would be what I would look at next. .

Edited: I've been thinking about the circuit board. It looks like the electricity arced to the gauge's ground. I wonder if wrapping the wire around the tan wire caused a loose ground and/or you have a bad wire/connection causing higher resistance & left the power on to long. A loose ground raises voltage upstream due to increased resistance. -(it doesn't increase amps) The voltage looks for an easier path to ground-thus the arc. Also the higher resistance would cause the gauge to peg high. SO I would definitely be looking at the tan wire and it's connections next