1. Injector Installation Issues:
* Incorrect installation: Fuel injectors are delicate. Did you install them correctly? Were the o-rings properly seated and lubricated? A damaged or misplaced o-ring will cause a leak, leading to a lean condition and preventing the engine from starting.
* Wiring: Did you reconnect all the injector wiring correctly? A single miswired injector can prevent the engine from running. Double-check the color-coding and ensure all connections are secure. A damaged wire is also possible.
* Fuel Rail Pressure: Was the fuel rail properly reinstalled and secured? A leak in the fuel rail will also prevent the engine from starting.
2. Other Potential Problems (Independent of the Injectors):
* Fuel Pump: Is the fuel pump functioning correctly? A faulty fuel pump won't deliver fuel to the injectors, regardless of their condition. You should hear the pump prime when you turn the ignition key to the "on" position (but not cranking).
* Fuel Filter: A clogged fuel filter can restrict fuel flow. This is especially important if the old injectors were clogged, and debris dislodged during removal could have blocked the filter.
* Ignition System: This includes the spark plugs, ignition wires, distributor cap and rotor (if applicable), ignition coil, and crankshaft position sensor (CKP). A problem in any of these components will prevent the engine from firing.
* Computer/PCM: The Powertrain Control Module (PCM) controls fuel delivery. A faulty PCM can cause all kinds of starting issues.
* Airflow Sensor/Mass Airflow Sensor (MAF): A faulty MAF sensor can prevent the engine from starting or running properly.
* Battery: A weak battery can prevent the starter from cranking sufficiently. Check the battery voltage.
* Security System: Some vehicles have anti-theft systems that can prevent starting if there's a problem with the system.
* Crankshaft Position Sensor (CKP Sensor): This sensor tells the computer where the engine is in its cycle to provide proper timing for the fuel injection and ignition. A faulty sensor will prevent the engine from starting.
Troubleshooting Steps:
1. Check for Fuel Pressure: Use a fuel pressure gauge to verify that fuel is reaching the fuel rail.
2. Inspect Injector Wiring: Carefully check all injector wiring connections for proper seating and any signs of damage.
3. Check Fuel Filter: Replace the fuel filter; it's inexpensive and a common source of problems.
4. Verify Spark: Check for spark at the spark plugs. Use a spark tester or a spark plug wire tester.
5. Check Battery Voltage: Ensure the battery is adequately charged.
6. Check Fuel Pump: Listen for the fuel pump to prime when the ignition is turned on.
7. Use a Scan Tool: A scan tool can read diagnostic trouble codes (DTCs) stored in the PCM, which can provide valuable clues about the problem.
It's highly recommended to systematically check these points. Start with the simplest and most likely causes (fuel pressure, wiring, spark) before moving to more complex diagnostics. If you're not comfortable working on your car's electrical system or fuel system, it's best to take it to a qualified mechanic. Improperly handling fuel systems can be dangerous.
