1. Fuel Pump Issues:
* Pump Failure: The most common culprit. The electric fuel pump might be burned out, worn out, or simply not receiving power. Check the pump's fuse, relay, and wiring for continuity and proper voltage. Testing the pump directly (with a temporary power source, carefully!) can confirm its operation.
* Pump Relay Failure: The relay controls the pump's power. A faulty relay will prevent the pump from activating even if the fuse is good. A simple swap with a known good relay is the easiest test.
* Fuel Pump Wiring: Corrosion, broken wires, or poor connections in the wiring harness between the pump, relay, and fuse box can interrupt power. Thorough inspection of the wiring is necessary.
* Fuel Filter Clog: A clogged fuel filter can restrict fuel flow to the point where the injectors receive insufficient pressure. Replace the filter.
2. Fuel Pressure Regulator Problems:
* Leakage/Failure: The regulator controls fuel pressure. If it's leaking or faulty, it might not maintain sufficient pressure for the injectors to operate. This often leads to low fuel pressure or even no fuel pressure at the rail. Testing fuel pressure at the rail is crucial.
3. Injector Issues (Less Likely in this case, but possible):
* Clogged Injectors: While less likely to cause a complete lack of fuel, severely clogged injectors *could* restrict flow enough to be mistaken for a fuel delivery problem. However, you'd generally see symptoms of poor running before a complete cutoff.
* Injector Wiring/Electrical Issues: Similar to the fuel pump, problems with the injector wiring or their electrical connections can prevent them from operating.
4. Other Potential Problems:
* Fuel Tank Issues: A completely empty tank, a stuck fuel sender unit, or even a collapsed fuel tank (less common) could theoretically affect fuel delivery.
* Ignition Switch Problems: Though less directly related to fuel delivery, a faulty ignition switch could prevent power from reaching the fuel pump relay.
Troubleshooting Steps:
1. Check the fuel pump fuse and relay.
2. Listen carefully for the fuel pump running when the key is turned to the "on" position (but not started). You might hear a faint whirring sound. If not, you have a strong indication of a pump, relay or wiring problem.
3. Test the fuel pump directly (safely!).
4. Inspect all fuel lines for leaks or blockages.
5. Replace the fuel filter.
6. Check fuel pressure at the fuel rail using a fuel pressure gauge. This is the most definitive test for fuel delivery issues.
7. Inspect the fuel pressure regulator.
8. Check the wiring to the fuel pump and injectors.
Because this is a classic car, some of these components might be harder to source, but a good mechanic specializing in older Cadillacs would be the most efficient way to resolve this. Remember to always exercise caution when working with fuel systems; they can be hazardous.
