1. Spark Verification:
* Spark Test: The most crucial step you've missed. Disconnect a spark plug wire from a plug, ground the end of the wire to a good metal part of the engine (be careful!), and have someone crank the engine. You should see a strong, blue spark. If not:
* Ignition Module: While you mentioned checking it, a faulty module can be intermittent. Try a known-good module if possible.
* Ignition Coil: Similarly, even if it seemed good initially, it could be failing to deliver sufficient spark. A coil tester would be best here.
* Crank Sensor: A bad crank sensor won't signal the computer to send the spark signal. This is a common cause of no-start.
* Distributor (if equipped): Inspect the distributor cap and rotor for cracks, carbon tracking, or corrosion. Replace if necessary.
* Wiring: Check all wiring related to ignition for damage, shorts, or loose connections.
2. Fuel Delivery Verification (Beyond Pressure):
* Fuel Injectors: You have fuel pressure, but are the injectors actually *injecting* fuel? You'll need a noid light to test if they're getting the electrical signal from the EEC-IV. No pulse = injector problem or wiring.
* Fuel Injector Electrical Connections: Look for corrosion or broken wires at the fuel injector connector.
3. EEC-IV (Computer) Related:
* Codes: Use a code reader to check for diagnostic trouble codes (DTCs) stored in the EEC-IV. These codes are crucial for pinpointing the problem.
* Computer Power and Ground: Ensure the EEC-IV is getting proper power and ground. Check its fuses and connections.
* Throttle Position Sensor (TPS): A faulty TPS can prevent the engine from starting. Check its voltage output with a multimeter (values should be listed in your repair manual).
4. Other Possibilities:
* Cam Sensor (if equipped): Similar to the crank sensor, a bad cam sensor prevents proper timing and firing order.
* Low Compression: Perform a compression test to check cylinder compression. Low compression in one or more cylinders indicates a major engine issue (worn rings, valves, etc.).
Troubleshooting Steps:
1. Spark Test (Most Important!): Do this FIRST.
2. Read Diagnostic Trouble Codes (DTCs): This will give you valuable clues.
3. Fuel Injector Pulse Test (Noid Light): Check injector operation.
4. Check for DTCs related to Crankshaft/Camshaft sensors.
5. Compression Test: If the other tests yield nothing, check this for severe mechanical issues.
Where to find help:
* Repair Manual: A Haynes or Chilton repair manual for your specific year and model Ranger is invaluable. It will have wiring diagrams, component locations, and diagnostic procedures.
* Online Forums: Search online forums specific to Ford Rangers (like the Ford Ranger forums). Many experienced mechanics are there and can offer guidance based on similar problems.
Remember safety first! Work in a well-ventilated area, and disconnect the negative battery cable before working on the electrical system. If you're not comfortable performing these checks, it's best to take it to a qualified mechanic.
