Thread: Help with installing RPM tach.

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This is a pretty noob question, but how do I go about installing one? My 79 Chevy pickup doesn't have one so I was going to buy one and install it. Also, could somebody help me on installing a temperature gauge, a volt gauge, and an oil pressure gauge? The truck has a "Gen" light for the altenator... can I use this hookup for the volt gauge? Thanks for any help.

The gauges you buy will come with detailed instructions, but essentially, all the gauges will have certain things in common, hook- up- wise.

There are two types of gauges. Mechanical and electric. The mechanical gauges read the info by means of a mechanical connection, and the electric ones use a remote sender screwed into the engine. Too hard to explain the differences here, but you will probably be using electric ones, as they are the most common ones you get at the local auto parts store.

Let's take tach first. There are 3 main wires to the back of the tach (a 4th one for illumination also....goes to your dash lights) One wire is keyed hot. When you turn on the key, it excites the tach. The second wire is a ground, and the third goes to the negative side (distributor side) of the coil. Your instructions will specify what goes where.

Volt meter is the easiest of all. Just find that same keyed hot connection, and run it to the + side of voltmeter, and run the other - side to ground connection.

Temp gauge will have 3 leads (maybe 4th for illumination) One goes to keyed hot, the 2nd to ground, and the "S" terminal goes to a special sender you will screw into the head or intake manifold, into a water passage. Do not use teflon tape on the sender, as it will cause the sender to not get a good ground to the engine. Put it in dry.

Oil pressure gauge is essentially the same as the temp gauge, but the "S' terminal wire goes to an oil pressure sender screwed into the oil galley somewhere. If you want to keep your idiot light, make up a Tee out of usually 1/8 inch NPT brass pipe, and a hardware store Tee, and screw the new sender into one part of the Te, and the old idiot light sender into the other. Or find a whole new place in the oil galley.

Don't use the gen light hookup for the voltmeter. Just come off the back of the ignition switch "I' terminal.

Without being there to show you, it is hard, as every car is different, but these basics and the instruction sheets should get you started.

Buy some extra 16 guage wire at the auto parts store, and some # 10 crimp on ring terminals, and butt connectors, as you will probably need them.

Thank you for the help man, I appreciate it.