SQ8 Diesel Injector Problems: Symptoms and Solutions

Had a very similar issue on my 2018 S7 diesel last year. Have some experience working on diesel engines, but injection systems need proper diagnostic equipment. The symptoms match what I experienced, poor engine performance, increased fuel consumption, and those smoking issues during acceleration. After basic maintenance checks revealed nothing obvious, I took it to a workshop. The actual problem was surprisingly simple, a faulty wiring connection to one of the injectors. The cable insulation had worn through, causing intermittent connection issues. The repair cost was 95 Euro including diagnostic time, which was reasonable considering the multiple symptoms. Before your workshop visit, sharing these details would help provide better guidance: Current mileage, Any engine warning lights, Type of fuel used recently, Service history, Engine sound changes While waiting for a workshop appointment, avoid pushing the engine too hard. These injection system issues can worsen rapidly under stress. Power loss and poor performance are clear indicators something needs attention soon. The good news is that modern diesel engines are quite robust, but electrical connections to injection components need proper diagnosis and repair equipment.

Mileage is 142761 KM, last service was 800 KM ago. The symptoms have gotten worse since my initial post. The engine now struggles more with cold starts and the fuel consumption has increased even further. The air coming from the exhaust shows dark smoke during acceleration. There is also a noticeable performance drop, especially when merging onto faster roads. I called the workshop and they suggested checking for a potential fuel leak first. They mentioned similar cases where damaged fuel lines or worn injector seals caused comparable symptoms. The high-pressure fuel system on these engines needs specialized diagnostic equipment to properly assess the issue. Will update once I have more information from the workshop visit scheduled for next week.

Thanks for the additional details about your SQ8. The symptoms you describe are getting worryingly similar to what I experienced before the repair on my S7. The cold start issues and increased dark smoke are classic signs of fuel delivery problems. When my injection system started acting up, I also noticed the performance getting progressively worse, especially during cold starts. The fuel consumption on my S7 diesel went up by almost 30% before I got it fixed. Based on your description, the workshop suggestion to check for fuel leaks first makes sense. In my case, the worn wiring was causing similar symptoms, but the high pressure fuel system can show identical issues from multiple causes. The specialized diagnostic equipment they mentioned was essential in pinpointing my problem. Given your recent service and the rapid onset of symptoms, I would suspect either an electrical connection issue like I had or a mechanical problem in the injection system. The dark smoke during acceleration suggests incomplete fuel combustion, which matches with both scenarios. Looking forward to hearing what the workshop finds. Make sure they check both the mechanical and electrical components of the injection system. The repair costs can vary significantly depending on the actual cause.

Thanks for the input. After seeing your responses, particularly about the electrical issues that can cause these symptoms, I better understand what might be happening with my SQ8. The fuel consumption and performance issues match exactly what you described with your S7 diesel experiences. My engine is definitely showing all the classic signs of fuel delivery problems, the cold starts are particularly concerning now. I will make sure to mention the potential electrical connections when I take it to the workshop next week. Good to know that the repair might not be as complex or expensive as I initially feared if it turns out to be wiring related rather than a major mechanical fuel system issue. Will definitely keep the engine load light until then, given how quickly these symptoms can worsen. The maintenance history should help speed up their diagnosis process. Looking forward to sharing what they find during the inspection, especially since these diesel injection issues seem fairly common. I appreciate the detailed responses about your similar experiences. Really helps to know what to expect during the diagnostic process.