1. Fuel Injectors:
* Clogged Injectors: This is a common problem. Fuel injectors can become clogged with debris, preventing fuel from spraying properly. You'll need a fuel injector cleaner or to have them professionally cleaned or replaced.
* Faulty Injectors: An injector might be completely malfunctioning and not opening at all. This requires testing or replacement.
* Injector Wiring/Connectors: Check the wiring harness going to each injector for broken wires, corrosion, or loose connectors. A bad connection will prevent the injector from receiving the signal to open.
2. Fuel Pump/Pressure:
* Weak Fuel Pump: The fuel pump might not be providing sufficient pressure to the injectors. Listen for the fuel pump whirring when you turn the key to the "on" position (before cranking). A weak pump will make a weaker-than-normal sound or might not run at all. You'll need a fuel pressure gauge to accurately test the pressure.
* Clogged Fuel Filter: A clogged fuel filter restricts fuel flow. Replace the filter—it's a relatively inexpensive and easy fix.
* Fuel Pump Relay: The relay that controls the fuel pump could be faulty. This is a simple part to replace and test (you can swap it with a similar relay to see if that solves the issue).
3. Engine Control Module (ECM) / Computer:
* ECM Malfunction: The ECM controls the fuel injectors. A faulty ECM can prevent the injectors from receiving the signal to open. This is more difficult to diagnose and often requires professional testing or replacement. (Note: 1983 cars had simpler computer systems than modern ones.)
* Sensors: Various sensors (e.g., crankshaft position sensor, throttle position sensor, air flow sensor) provide the ECM with information to control fuel delivery. A faulty sensor can cause the ECM to make incorrect calculations leading to no fuel injection. These need testing with a multimeter or a scan tool.
4. Ignition Control Module (ICM) (Less likely given you have spark):
* While you mention spark, a faulty ICM could still be a contributing factor, especially if the spark is weak or intermittent.
Troubleshooting Steps:
1. Check Fuel Pressure: Use a fuel pressure gauge to measure the fuel pressure. This is crucial to eliminate fuel pump issues.
2. Inspect Fuel Filter: Replace the filter regardless; it's a cheap preventative measure.
3. Check Injector Wiring and Connectors: Look for any visible damage, corrosion, or loose connections.
4. Listen for Fuel Pump: Listen for the fuel pump's priming sound when you turn the key to the "on" position.
5. Visual Inspection: Carefully inspect all fuel lines for leaks or cracks.
Important Safety Note: Working with fuel systems can be dangerous. Be mindful of fire hazards, and work in a well-ventilated area. If you're not comfortable working on fuel systems, take your car to a qualified mechanic.
Because your car is an older model, finding diagnostic tools specifically for it might be challenging. A generic OBD scanner likely won't work. You may need to consult a repair manual specific to your 1983 Lincoln Mark VI, or seek professional help. The manual will have wiring diagrams and troubleshooting guides specific to the fuel injection system of your model.
