1. Choosing the Right Tach:
* Type: Get a tachometer specifically designed for negative (-) ground systems (most cars are). The Cavalier is negative ground.
* Signal Input: Ensure the tach is compatible with receiving a signal from an ignition coil or a distributor. The 1997 Cavalier likely uses a distributor.
* Features: Consider features like peak RPM memory, shift light, and gauge illumination matching your dashboard.
2. Identifying the Signal Source:
This is the most crucial step. You need to find a wire that pulses with each engine revolution (or a multiple thereof). There are two main options:
* Distributor: The most common method is to tap into the distributor's coil wire. This wire delivers a high-voltage pulse to the spark plugs. Caution: This is a high-voltage wire; be extremely careful and disconnect the negative battery terminal before working near it. You'll need an inductive pickup (often supplied with the tach) to avoid directly connecting to the high-voltage wire. The inductive pickup clamps around the wire, sensing the pulses without direct connection.
* Coil Wire (If No Distributor): Some 1997 Cavaliers *might* have a coil-pack system, eliminating the distributor. If so, consulting a wiring diagram is crucial. You’ll need to identify the wire carrying the pulse to one of the ignition coils. Again, an inductive pickup will be safer and easier than tapping into the high voltage side.
3. Wiring the Tach:
After selecting your signal source, you'll need to connect the tachometer's wires. The specific wiring will vary depending on the tachometer model, but generally, you'll need to connect:
* Power: Usually a switched 12V (+12V when ignition is on). You can find a suitable wire under the dash by using a test light or multimeter.
* Ground: A solid ground connection to bare metal on the car's chassis.
* Tachometer Signal: This is the wire connected to your inductive pickup (if using) or directly to the coil wire (only if using an appropriate low-impedance input on the tachometer, and with extreme caution). Consult your tachometer's instructions.
* Illumination (optional): Some tachometers have a light to match your dash. This can be wired to the dash illumination circuit.
4. Routing the Wires:
Carefully route the wires along existing wiring harnesses to conceal them and prevent damage. Use zip ties to secure the wires.
5. Testing and Mounting:
After connecting everything, reconnect the battery. Start the car and verify the tachometer is working correctly. If not, double-check all connections. Then, mount the tachometer in a suitable location on the dashboard.
Important Considerations:
* Wiring Diagram: Obtain a wiring diagram for your specific 1997 Chevy Cavalier model. This is invaluable for identifying the correct wires. You can often find these online through forums or repair manuals.
* Safety: Disconnect the negative battery terminal before starting any work on the electrical system. High voltage can cause serious injury.
* Professional Installation: If you are uncomfortable working with car electrical systems, it's best to have a qualified mechanic install the tachometer.
This process involves working with electricity. If you're not comfortable with automotive electrical systems, it's best to seek professional help. Incorrect wiring can damage your car's electrical system or even cause a fire. Always refer to the wiring diagram and the instruction manual provided with your specific tachometer.
