How to "Plumb" Gauges?

1989MustangLX said:

I bought a gauge pod with three 2" mechanical gauges. Water Temp, Oil Pressure, and Amperage. I am not exactly sure where I want to mount it yet, but I dont know how to get the lines from the gauges to the fittings on the engine. The dash is all still in the car too. Thanks for anyone with an idea for me to try.

Edit: Added "Mechanical".

Click to expand...

An ampmeter on a car with an alternator is not as good as a voltmeter. The voltmeter is a much better indicator of the electrical condition of the alternator equipted system. Unless your ampmeter uses a remote shunt, you would have to run 2 each 8 gauge minimum size wires to the ampmeter to get it to work. The 8 gauge wire would be about 5/16" diameter and two of them would take up a lot of room in an A pillar pod arrangement.

A voltmeter only needs 2 small 18 gauge wires power & ground, and could share the ground with the gauge illumination.

True true words from JR! It is more than worth your while to swap that gauge in. I have run ammeters on stuff with generators, regulator/rectifiers and they are worrysome (to me).

If you search posts in here, you should find most of the info you seek. You can daisychain the connections at the gauges themselves, so you only have one 12 volt key-on feed, one ground feed, one illumination feed, etc.

For illumination you can hit the dimmer wire at the back of the headlight switch or fuse 13. If using the latter, use the dead side of the fuse and fuse your new wire with the smallest fuse you can find (so if your wiring is bad, you hopefully dont take out your stock cluster illumination - so you can see your stock instruments till you get home).

If you cant find a large hole in the firewall for the sender bulbs (autos should have an extra hole where clutch linkage would go), then a step drill bit (unibit) might help with the hole drilling.
Good luck.

You have to run them through the firewall. Not sure if you could use exisiting holes or if youd have to make your own. Step one is to figure out where you want them mounted. Step two is figuring out how to run the plumbing. Have you decided on a spot yet?

Oops, you posted while I was pecking. disregard the ammeter, etc stuff.

I'm doing the same thing tomorrow, but using a gauge cage. For my other gauges, i did the wiring like they said, one ground, one ignition soure and the illumination power wires to a key on source that is controlled by a switch(so the lights are only on when i want em).


Anyone know if there is an existing firewall hole behind the vents i can use?