Golf Hybrid Cold Start Issues Need Expert Diagnosis

Had similar issues with a Golf GTE from a slightly older production year. The cold start problems and rough idle turned out to be a faulty fuel injector. The symptoms matched exactly, hard starting in the morning and unstable running until the engine reached operating temperature. The diagnosis required specific fuel system testing, including injection pulse width measurement and back-pressure tests. A proper mechanic should use computerized diagnostics to monitor fuel delivery patterns and injector response times. The faulty injector was not delivering the correct fuel spray pattern during cold starts. This is a serious issue that needs prompt attention as it can lead to: Increased emissions, Further fuel system damage, Potential catalytic converter problems, Decreased fuel efficiency The repair involved replacing the problematic injector and performing a full system calibration. Important to have the fuel pressure tested as well, since low pressure can sometimes mimic injector problems. Make sure to get a complete fuel system diagnostic before replacing parts. A competent shop should be able to pinpoint whether its truly an injector issue or related to other fuel delivery components.

Thanks for the detailed insight on the fuel injector issue. My symptoms were identical, rough engine performance and hard starting until warm. The injector test confirmed uneven spray patterns and the engine misfire disappeared completely after fixing it. Quick follow up, do you recall the repair costs? Also wondering if youve had any other fuel injection problems since getting it fixed? Im considering having all injectors cleaned preventively while they do the repair.

Thanks for asking about the costs. Since getting the faulty cold start injector replaced, the starting issues and rough running completely disappeared. The total repair came to 515€, which included the new injector, labor, and system calibration after installation. Have not experienced any fuel injection problems in the thousands of kilometers since the repair. While preventive injector cleaning sounds sensible, its not always necessary if the fuel delivery system is functioning properly. The diagnostic tests showed the other injectors were performing within spec with good spray patterns. A thorough fuel injection system test is the best way to determine if additional injectors need cleaning or replacement. If the test results show all other injectors are delivering fuel correctly, cleaning them might be an unnecessary expense. The fuel rail and remaining injectors showed no signs of deposits or restrictions during testing. Consider using high-quality fuel and fuel system cleaners periodically as preventive maintenance. This helps maintain proper injector function and fuel delivery over time.

After dealing with those cold start issues for weeks, I finally took it to a reputable shop specializing in fuel system diagnostics. Their testing confirmed what suggested, a faulty injector causing inconsistent fuel delivery during cold starts. The repair process went smoothly. They ran comprehensive fuel injection testing, replaced the problematic injector, and recalibrated the system. The engine misfire issues disappeared completely. Total cost was 490€, which included parts and labor. The improvement was immediate, no more rough running or hard starts in the morning. Been driving for several weeks now without any fuel delivery problems. Really glad I got it properly diagnosed instead of continuing with band-aid solutions. For anyone facing similar symptoms, make sure to get proper fuel system diagnostics done by a qualified shop. The right testing makes all the difference in pinpointing these kinds of issues.