Struggling with an electrical oil pressure gauge installation

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Nov 21, 2020
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185
Hi guys,

Really struggling here. This isnt my first rodeo, and for the life of me I cant get my new electrical oil pressure gauge to sweep.

Its a Bosch gauge, I crossed all my tees and dotted my eyes. I've double checked the grounds, and where possible used crimp fittings or solder/heat shrink.
I actually ended up grounding the bulb (-) and the gauge (-) directly to the battery. 12v supply comes from the DRL and Cigar sockets using mini add-a-circuit connectors. I swapped the (-) and (+) to see if it was pulling in reverse, and nothing. The sending unit is on a tee with the stock oil pressure switch.

I flipped both back and fourth, used new fuses etc.....Although I may double check the fuses when I have some light again.

The sending unit isnt grounded......and it didnt specify to in the instructions. I even tried a ground on the base to the battery (-) to see if that did it.

Any thoughts? Faulty sender or gauge?

It sure looks pretty lit up......but thats about it!
 
Link to manual?

I take it it's showing zero PSI?

Are you sure it's getting oil?
 
Hi guys, thanks for checking in. I'm going to check in with a meter when its light out, to make sure its getting power.

What kind of reading - if any, should I get from a properly functioning sending unit? I'm sure its getting oil. I'll snap a photo of the install and repost it tomorrow.

Red and black wire from the blub.....black to ground, and red picking up switched 12V

Red, black and white from the guage......Red to switch 12V, black to ground (ganged with the bulb ground) and the white to the sending unit
 
Had a mechanical gauge do same thing once. This was after it had worked fine. The problem??? A piece of teflon tape had gotten stuck in the end of the gauge. It actually had some oil pressure trapped as it "spit" out some oil when removed. Could be the same for your gauge. Good Luck!!!
 
Wire colors aren't universal. We could help if you linked to the installation manual.
 
Check that the 12 volt power is actually 12 volts or more with the engine running. Connecting it to the DRL circuit doesn't seem like a good source.

If you ground the sender wire with the power on, the gauge needle should go all the way up. You can also do this test outside the car on the workbench with a battery. This tests the gauge head independent of the sender.

Disconnected from the gauge, the sender is just a variable resistor to ground. It should measure tens to hundreds of ohms with the engine stopped, and less with it running due to the oil pressure. (test to engine ground not battery - or whatever ground you're using inside the cab. If you're going to run a gauge ground wire under the hood, connect it to the engine.) This is how to test the sender independent of the gauge head.
 
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Thanks guys, Chris142, much appreciated, and thanks for all the comments. Its pitch black right now, so I'll report back tomorrow.

This is the instruction sheet......


The gauge is the chrome 2" Style-line electronic oil pressure gauge, with the mount.


Just to clarify, I dont have a ground on the sending unit Tee, or housing......oh crap.....maybe thats it. The sending unit is mounted away from the black, separated by a rubber hose.....I'm guessing thats why they dont suggest grounding the sender.

I'll find a proper way to ground the sending unit in the AM, and report back
 
Thanks again guys.

I got it!

There were extra washers and nuts in the gauge kit, that I installed to secure the tag with the (-) (+) and (s) markings

The washers were bottoming out on the housing of the gauge, causing an instant short (duh)

This in turn, blew one of my 10 amp fuses, and then, because it was an odd ball install, it needed and additional ground to the body of the sending unit.

She's alive!
 
I wanted to avoid gauge and your engine is blown light (exaggeration I know) on the same circuit so I got a decent gauge with Japanese motor with low pressure warning (noise and flashing light) and set it 15psi and just run that and no light. The light goes off after a few seconds anyway and comes on much lower than 15 psi. Much nicer setup with fewer leak points, I added a water temp also with warning.

This is the 3 wire sender, the only one I found so far outside of OE that clears the alternator it uses a weatherproof connector.



IMG_0015.JPG
 
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