SQ8 Running Rich, Key Signs of Fuel System Troubles

Had nearly identical symptoms with my S7 (2017) last summer. The main issue turned out to be multiple faulty fuel injectors affecting the air-fuel ratio. The symptoms matched exactly, poor fuel economy, rough idle, reduced power, and the check engine light was constantly on. The injectors were sticking open, dumping excess fuel into the cylinders. This caused the engine to run rich, leading to poor combustion and the jerking sensation during acceleration. The repair involved replacing all affected injectors and cleaning the fuel system. This is considered a serious issue since faulty injectors can: Cause internal engine damage if left unchecked, Lead to catalytic converter failure, Create unsafe driving conditions due to power loss The diagnosis process included: Computer diagnostic scan, Fuel pressure testing, Spark plug inspection (they were black and fouled from excess fuel), Testing each injector individually Worth checking the air filter too, as a clogged one can contribute to similar symptoms, but given the symptoms described, injectors are likely the primary concern. Recommend getting it checked soon, as running too rich can cause additional problems over time.

Thanks for sharing your experience with the S7. I had pretty much the exact same thing happen with my SQ8. Turned out the intake manifold was cracked, causing both pressure and air-fuel ratio issues. The symptoms were spot on, rough running, check engine warnings, and terrible fuel economy. The shop confirmed it was running a rich mixture. Did you happen to remember the repair cost for your injector work? Also curious if youve had any issues pop up since the fix? Just asking since Ive had zero problems after my repair, but always good to know what to watch out for with these engines.

Thanks for asking about the follow-up. The injector repair on my S7 cost 515 Euro total, including parts and labor. The fix completely resolved the rich fuel mixture issue, and the engine has been running flawlessly since then. After replacing the faulty injectors, I noticed immediate improvements: Fuel economy returned to normal, Engine power was fully restored, Rough running completely disappeared, Check engine light stayed off The oxygen sensor readings confirmed the engine was no longer running rich. The spark plugs stayed clean during the next inspection, showing the fuel mixture was properly balanced. My mechanic did a thorough job testing each new injector to ensure proper spray patterns and timing. Its been over 8 months now with no related issues. The catalytic converter also survived the ordeal since we caught the problem relatively quickly. Just make sure to keep an eye on your fuel consumption, its usually the first sign if something starts going wrong again with the fuel system.

Thanks for the input. Just wanted to share how my repair went in case others run into similar issues. Took it to a new shop this time after reading reviews carefully. The cracked intake manifold repair ended up costing 780 Euro with parts and labor. The mechanic showed me the crack, it was pretty obvious once they got in there. They also cleaned the entire intake system while they were at it. The difference after repair was night and day: Check engine light cleared immediately, Fuel economy went back to normal, No more jerking during acceleration, Engine power fully restored The oxygen sensor readings confirmed everything was working properly. Been about 3 months now with zero issues. Really glad I got it fixed when I did, the mechanic mentioned running with a rich mixture could have damaged the catalytic converter if left unchecked. For anyone else seeing these symptoms, definitely get it checked out sooner rather than later. The repair wasnt cheap, but it was worth it to prevent more expensive problems down the road.