1. Verify Ignition System Components:
* Coil: Is the coil producing a strong spark? Use a spark tester (a gap between two wires) connected to the coil wire and ground. A good coil should produce a fat, blue spark. If weak or no spark, replace the coil.
* Distributor Cap and Rotor: These are common points of failure. Inspect for cracks, carbon tracking, or corrosion. Replace them if necessary. Make sure the rotor is properly seated and spins freely.
* Ignition Module (HEI): The 1979 Corvette likely has a High Energy Ignition (HEI) system. These modules can fail. A faulty module won't produce a spark, even if the coil and other components are good. Testing a module can be tricky; it's often easiest to replace it as a diagnostic step if other components check out.
* Pick-up Coil (within the distributor): This sends the signal to the ignition module. While less common than other issues, a faulty pick-up coil can prevent spark. Testing requires a multimeter and specific knowledge of the HEI system.
* Wiring: Inspect all wiring related to the ignition system for broken or corroded connections. Pay close attention to the wires between the distributor, coil, and ignition module.
2. Confirm Fuel Delivery:
While you say you're getting fuel, it's crucial to go beyond just 12V to the distributor. The distributor doesn't directly control fuel.
* Fuel Pressure: Use a fuel pressure gauge to check the fuel pressure at the fuel rail. It should be within the manufacturer's specifications (check your shop manual). Low pressure indicates a problem with the fuel pump, filter, or regulator.
* Fuel Injectors (if applicable): Does your '79 have fuel injection or a carburetor? If fuel injection, check for injector pulse. You might need a noid light to test this. If a carburetor, check for proper fuel flow into the carburetor.
* Air/Fuel Mixture: Even with fuel, if the air/fuel mixture is severely off (e.g., flooded engine), it won't start.
3. Compression Test:
Low compression in one or more cylinders prevents starting. Perform a compression test to rule out this critical issue. Low compression could be due to worn rings, valves, or head gasket problems (despite the head replacement).
4. Timing:
While you've retimed the engine several times, double-check the timing marks. Even a slight error can prevent starting. Use a timing light to verify the timing is accurate. Incorrect timing can be a significant hurdle.
5. Crankshaft Position Sensor (CKP): Some 79 Corvettes might have a CKP. If this sensor is failing, it won't send the correct signal to the computer, preventing a spark.
6. Check the basics:
* Battery: Make sure your battery is fully charged and has sufficient cranking amps.
* Grounds: Poor ground connections can cause all sorts of electrical gremlins. Clean all ground straps.
Troubleshooting Steps:
1. Start with the easiest: Check the obvious things first: battery, grounds, coil spark.
2. Systematic Approach: Work through the ignition system components one by one.
3. Use a multimeter: To test voltage and continuity in the electrical system.
4. Consult a Repair Manual: A factory service manual for your 1979 Corvette is invaluable. It provides detailed wiring diagrams, specifications, and troubleshooting procedures.
If you've done all this and still have no luck, it's time to seek help from a qualified mechanic experienced with classic Corvettes. They have the tools and expertise to diagnose more complex problems. Remember safety first—always disconnect the battery negative terminal before working on the electrical system.
