1. Verify the obvious (but crucial):
* Battery Voltage: A weak battery can manifest as no spark. Test the battery voltage with a multimeter. It should be around 12.6V when not cranking, and above 10V while cranking.
* Fuses and Relays: Check all fuses related to the ignition system and the fuel pump (even though you replaced the pump, a blown fuse could affect other ignition components). Consult your owner's manual for fuse locations and ratings. Also inspect all relays visually for any damage.
* Ignition Switch: A faulty ignition switch can prevent power from reaching the ignition system. Try wiggling the key while someone attempts to start the car. If the engine starts intermittently, the switch might be suspect.
2. Test for Spark at the Spark Plugs:
* Disconnect a spark plug wire: Disconnect one spark plug wire from a spark plug. Ground the end of the wire by holding the metal part of the wire near a good ground point on the engine block (wear gloves for safety).
* Have someone crank the engine: While the engine is cranking, observe the spark plug wire. You should see a bright blue spark jumping the gap. If there's no spark, the problem is further up the ignition system. Repeat this for all cylinders. A weak spark could also indicate problems.
3. Investigate Components in the Ignition System (If no spark):
* Ignition Coil: A faulty ignition coil is a common cause of no spark. These coils are relatively inexpensive and easy to test with a multimeter (check your owner's manual or online resources for your specific engine for testing procedures, often involving resistance checks). A visual inspection for cracks or damage is also wise.
* Crankshaft Position Sensor (CKP): This sensor tells the ignition control module when to fire the spark. A faulty CKP sensor won't allow the ignition system to function. You'll need a multimeter or an OBD-II scanner to test its signal.
* Camshaft Position Sensor (CMP): Similar to the CKP sensor, a faulty CMP sensor (if your engine has one) prevents proper timing of the ignition. Test this sensor as well using a multimeter or OBD-II scanner.
* Ignition Control Module (ICM): You replaced this, but it's worth considering if the replacement is faulty (though less likely). These are typically more complex to test without specialized equipment.
* Wiring: Check all wiring related to the ignition system for damage, corrosion, or loose connections. This includes the wires from the ignition coil, the sensors, and the ignition switch.
4. Diagnostic Tools:
* OBD-II Scanner: A code reader can help diagnose problems with the ignition system by reading diagnostic trouble codes (DTCs) stored in the car's computer.
* Multimeter: Essential for testing voltage, resistance, and continuity in various components.
5. Professional Help:
If you're not comfortable working with automotive electrical systems, it's best to take the car to a qualified mechanic. Incorrect diagnosis and repairs in the ignition system can cause further damage.
Important Safety Note: Always disconnect the negative battery terminal before working on any automotive electrical system. This will prevent accidental shorts and injuries. Be aware that high voltage is present in the ignition system even when the car is off; exercise caution.
