I have a V8 swapped '77 z & I can't determine what wires go to the oil & fuel guages. I have the wiring diagram but the wires keep going through plugs that don't show which wires come out the other side. I've tried grounding all the spare wires under the hood, but none of them move the oil guage. Ditto with the wires in back for the fuel guage - I have one square plug (three wires), one round plug (also three wires IIRC), & two wires that have male & female round (pin) ends.

Anyone with a '77 that can check these for me?

Thanks heaps in advance,

~ Paul
aka "Tha Driver"

The wire back to the fuel sending unit should be yellow if the wiring hasn't been molested too badly.  At the back of the car, there should also be a yellow/blue wire and a black wire. The yellow/blue wire is connected to a thermistor on the sending unit for the low fuel light. The black wire is a ground.

The stock wiring for the oil pressure sensor is yellow blue. In the stock wiring, it should have a bullet or ring connector to attach to the oil pressure sender mounted in the lower middle of the block on the passenger side. The wire should go back into the wiring harness and connects to the dash harness. It in the same position for pretty much every S30 and S130.

 

You can also look for the voltage signal on these wires using a multimeter if the key is in the ON position. Ground the negative probe and test the wire of interest with the positive probe. You should see the voltage fluctuate for the fuel gauge wire and for the oil pressure gauge wire.

Finally, consider posting photos of what you're looking at. It usually easier to figure out what you are looking at if you post close-in and zoomed out photos of where you are looking.

On 10/12/2022 at 3:26 AM, Tha Driver said:

oil & fuel guages.

 

On 10/12/2022 at 3:26 AM, Tha Driver said:

the oil guage.

 

On 10/12/2022 at 3:26 AM, Tha Driver said:

the fuel guage

 

As am learning some english... americano (?)...  I took a look at guage but my translator is stupid and does not see the difference between the Gauge and the guage..  I think it's gauge not guage as it does not excist in english..??  (sorry for my nitpicking haha)

On 10/12/2022 at 3:42 AM, SteveJ said:

the fuel gauge

 

On 10/12/2022 at 3:42 AM, SteveJ said:

the oil pressure gauge

So steve got it right...   but i can see that gu-age is a good word for that meter on dash.. as you say: gééh-jjdts.. sort of  😉 

so my question is.. does the word guage excist in the american language or is it just gauge?

Guage doesn't exist in American English, but just to complicate or simplify matters, gage is another acceptable way to spell it.

I thought "guage" looked funny, but couldn't put my finger on it... I'm getting old...

Sooo, it's the round plug for the fuel sender. Thanks to you guys, I connected the black & the yellow wire together & got the fuel gauge to peg. So all I have to do is connect both of them to my sending unit (fuel cell with aftermarket sending unit).

My camera is having problems, but I'll post pics when I get it working again.

Now I'm thinking the oil pressure gauge may be the same - needing not only the sending unit wire connected to something but also grounded. Does the original oil pressure sending unit have more than one wire going to it? Mine just grounds the gauge (with one wire), it's a Small block Mopar.

Thanks so much guys (& gals),

~ Paul
aka "Tha Driver"

Nevermind - I just looked back at the post & saw the oil pressure sending unit pic. One wire should ground the gauge. I'll keep trying when I get a chance.

I'm currently suffering from the after effects of shingles, well over a year after getting it. Sharp stabbing pains in my chest & side every few minutes or hour or so (it varies). It's put me WAY behind in my work on customer's cars, so I have to work on them before my projects when I CAN work. If you had chicken pox as a kid, GET THE SHINGLES VACCINE NOW! It's WAY worse than anything you read about it & the "permanent nerve damage" talked about apparently means a LIFETIME of INTENSE pain & suffering. Of course the doctors don't care how much pain you're in these days, & have refused to prescribe any effective pain meds. :-(

Thanks again,

~ Paul
aka "Tha Driver"

Thanks Mark, so the gage or gauge is the metering instrument on the dash and also the thickness of say steel plate.  

I never know what one means with 10 gauge steel or wire or so... talk in mm!!  (Millimeters!!)  THAT i understand hahaha..