Symptoms of a Stuck Open Injector:
* Rough running engine: This is a common symptom. The cylinder that's getting too much fuel will misfire, causing a rough idle and potentially noticeable shaking.
* Poor fuel economy: Excessive fuel is being wasted.
* Black smoke from the exhaust: Unburnt fuel is being expelled. This is a strong indicator.
* Engine hesitation or stalling: The extra fuel can overwhelm the engine's ability to combust properly.
* Check Engine Light (CEL): This will almost certainly illuminate, and a diagnostic code related to a misfire in a specific cylinder will be present. You'll need a code reader to interpret this.
* Possible engine damage (over time): Continuous over-fueling can wash away the cylinder wall lubrication and cause significant engine damage if not addressed.
Symptoms of a Stuck Closed Injector:
* Rough running engine: Similar to a stuck open injector, but the misfire will be more noticeable due to the lack of fuel.
* Loss of power: A significant reduction in engine performance.
* Hard starting: The engine may struggle to start or crank for a longer time.
* Check Engine Light (CEL): This will illuminate, showing a misfire code related to the affected cylinder.
* Poor fuel economy (less likely than stuck open): While less pronounced, the engine may show slightly better fuel economy because it's using less fuel. However, this is often overshadowed by the loss of power and need to work the engine harder.
Diagnosing a Stuck Injector:
Pinpointing the *exact* injector requires a more technical approach:
1. OBD-II Scanner: This is the first step. Retrieve diagnostic trouble codes (DTCs) from the vehicle's computer. Misfire codes pointing to a specific cylinder strongly suggest a problem with that cylinder's injector.
2. Injector Leak Down Test: A specialized test to check if an injector is leaking fuel while the injector is in the resting (closed) state.
3. Injector Flow Test: Checks the amount of fuel delivered by each injector over time. A blocked or faulty injector will deliver less fuel than a properly working one. This usually requires removing the injectors and testing them on a fuel flow bench at a repair shop.
4. Visual Inspection (Advanced): Carefully examine the injectors and their wiring for signs of damage, corrosion, or leaks. This can sometimes reveal a stuck injector if there's obvious physical blockage.
Important Note: Don't attempt major repairs unless you have the proper tools, experience, and safety precautions. A mechanic specializing in vehicle diagnostics and fuel systems can properly diagnose and repair a stuck injector. Ignoring a stuck injector can lead to serious engine damage.
