Here are more likely culprits for fuel flooding at a single injector:
* Injector itself: The most probable cause is a faulty injector. It could be sticking open, allowing a continuous flow of fuel even when not commanded by the engine control unit (ECU).
* Injector wiring harness: A short circuit in the wiring harness to that specific injector could be sending a constant signal to the injector, causing it to stay open. Check for chafing, damaged insulation, or corrosion.
* ECU (Engine Control Unit): While less likely than a faulty injector, a malfunctioning ECU could be sending incorrect signals to that single injector. This is harder to diagnose without specialized equipment.
* Fuel pressure regulator: A faulty fuel pressure regulator could be causing excessive fuel pressure in the system, leading to an injector staying open or leaking.
Troubleshooting Steps:
1. Visual Inspection: Carefully examine the injector and its wiring harness for any signs of damage, corrosion, or leaks.
2. Fuel Pressure Test: This is crucial. A fuel pressure gauge will tell you if the fuel pressure is excessively high. This helps rule out the fuel pressure regulator.
3. Injector Test: The best way to definitively test the injector is to use an injector tester or have a mechanic perform a comprehensive fuel system diagnostic. This will determine if the injector is sticking open or functioning correctly.
4. Resistance Test (Injector): You can also check the electrical resistance of the injector with a multimeter. Compare it to the specifications in a repair manual to see if it's within range.
5. Ohm Test (Wiring): Check the resistance of the wiring from the ECU to the suspected injector. A short circuit will show a lower than expected resistance.
Before attempting any repairs: Disconnect the negative battery terminal to prevent accidental shorts or sparks. Work in a well-ventilated area, as fuel is flammable.
If you're not comfortable working on fuel systems, it's best to take your Sunfire to a qualified mechanic for diagnosis and repair. Trying to diagnose and fix fuel system problems without the proper tools and knowledge can be dangerous.
