Safety First: Always disconnect the negative battery cable before working on any electrical components.
1. The Basics:
* Battery: Check the battery voltage with a multimeter. It should be around 12.6 volts when fully charged. If it's low, charge it or replace it. Also check the battery terminals for corrosion and clean them if necessary.
* Starter: Does the engine crank over when you turn the key? If not, the problem might be the starter motor, battery cables, or the ignition switch itself – not necessarily the ignition system.
* Fuses and Relays: Check the fuses and relays related to the ignition system. Your owner's manual should have a fuse box diagram. Look for any blown fuses or damaged relays.
2. Ignition System Components (In order of testing):
* Ignition Switch: Make sure the ignition switch is functioning correctly. Try turning the key to different positions and see if there are any clicking noises or other unusual sounds. A faulty switch won't send power to the ignition system.
* Crankshaft Position Sensor (CKP): This sensor tells the computer the engine's position. A faulty sensor prevents the computer from sending the signal to fire the spark plugs. Testing requires a multimeter and a wiring diagram to check for continuity and signal voltage. Usually, a bad CKP sensor will result in a no-crank or no-start condition.
* Camshaft Position Sensor (CMP): Similar to the CKP sensor, this tells the computer the camshaft's position, crucial for precise spark timing. Testing is similar to the CKP sensor – multimeter and wiring diagram are needed.
* Ignition Control Module (ICM): This module receives signals from the sensors and the computer and triggers the spark. These are often hard to test at home without specialized equipment. Swapping it with a known good one is the easiest diagnostic method if available.
* Ignition Coil: This coil amplifies the low voltage signal from the ICM to create the high voltage needed for the spark plugs. Testing can be done with a multimeter to check for resistance and also visually inspect for cracks or damage. A simple test involves pulling a plug wire, holding it about 1/4 inch from the engine block, then cranking the engine and looking for a strong spark. If there's no spark, the ignition coil could be the issue. However, if you see a weak spark, the problem lies elsewhere.
* Spark Plug Wires: Check for cracks, fraying, or damage to the wires. Ensure they are securely connected to both the spark plugs and the distributor cap (if applicable). A simple test is to check the resistance of each wire with a multimeter; too much resistance indicates a bad wire.
* Distributor Cap and Rotor (if applicable): Inspect the distributor cap and rotor for cracks, corrosion, or burnt areas. The rotor should make good contact with the cap. Replace if necessary.
* Spark Plugs: Inspect the spark plugs for wear, fouling, or damage. Replace them if necessary.
3. Testing for Spark:
The easiest way to test if you are getting spark is to use an inline spark tester on a spark plug wire. These are readily available at auto parts stores. This bypasses several components and quickly reveals if the spark is even reaching the wires.
4. Professional Help:
If you're not comfortable with electrical testing, it's best to take your Corvette to a qualified mechanic. Diagnosing ignition problems can be tricky, and incorrect troubleshooting could lead to further damage.
Remember to consult your 1993 Corvette's repair manual for specific diagrams and testing procedures. This will make troubleshooting much easier and safer. Good luck!
