🚨 Diagnostic Profile
Vehicle Make: BUICK
Code/Description: Injector Circuit Cylinder 8 Intermittent
This fault indicates an intermittent electrical disruption in the fuel injector circuit for cylinder 8, likely caused by a damaged wiring harness, a failing connector, a degraded injector driver within the Engine Control Module (ECM), or an intermittently failing injector solenoid. Because the fault is intermittent rather than constant, it often points toward a wiring or connector issue that is sensitive to heat, vibration, or movement rather than a fully failed component.
🚨 Repair Difficulty Tier
Difficulty Rating: Intermediate
This repair requires a diagnostic scan tool capable of reading live injector pulse data and circuit status, along with a digital multimeter to test resistance and voltage drop across the injector circuit. While replacing an injector or repairing wiring is within reach of an experienced DIY mechanic, accurately diagnosing an intermittent fault requires patience, knowledge of wiggle-testing techniques, and the ability to interpret live scanner data. Incorrect diagnosis can lead to unnecessary parts replacement, so this is best handled by someone comfortable with automotive electrical systems.
🛠️ Resolution Steps
Step 1: Preliminary Inspection
Begin by visually inspecting the wiring harness and connector leading to the cylinder 8 fuel injector. Look for chafed insulation, corrosion, heat damage, or loose pins at the connector. Gently wiggle the harness near the injector and along its routed path while watching for any changes on a connected scan tool to help identify intermittent connection points. Also inspect the injector body itself for signs of oil contamination or electrical arcing at the terminals.
Step 2: Diagnostic Verification
Connect a scan tool capable of reading manufacturer-specific live data and monitor the injector pulse width and circuit status for cylinder 8 while the engine is running or cranking. Use a digital multimeter to check circuit resistance (typically within OEM specification, often between 12-16 ohms for similar GM injectors) and check for voltage drop across the circuit under load. Perform a wiggle test on the harness while monitoring live data to catch the intermittent fault in action. Compare readings to a known-good cylinder to confirm whether the issue lies in the injector, wiring, or ECM driver circuit.
Step 3: Resolution & Reset Process
If wiring or connector damage is found, repair or replace the affected harness section and connector, ensuring all pins are properly seated and terminals show no corrosion. If the injector itself tests faulty (open or shorted circuit, inconsistent resistance), replace the injector with an OEM or OEM-equivalent part. After repair, clear the diagnostic trouble codes using the scan tool and perform a test drive while monitoring live data to confirm the circuit remains stable under various engine conditions. Perform a final verification scan to ensure no codes return.
📦 Parts, Labor, and Budget Estimates
Required Components/Software: OEM fuel injector (cylinder 8), wiring harness repair kit or connector pigtail, dielectric grease, bi-directional scan tool with live data capability, digital multimeter.
Average Component Price: $45–$150 for a replacement injector (OEM or OEM-equivalent), $20–$60 for a harness repair kit or connector pigtail if wiring replacement is needed.
Estimated Labor Hours: 1.0–2.5 hours for diagnostic verification and testing, plus an additional 0.5–1.5 hours for injector or wiring replacement depending on accessibility.