Rainier Engine Knock Signals Severe Detonation Issues

Had similar issues with a 2003 Rendezvous with the 3.6L engine. Started with rough acceleration and engine knock during load. Diagnostic tests confirmed carbon deposits in the combustion chamber causing pre-ignition. The repair involved: Removing carbon buildup from valves and combustion chamber, Replacing spark plugs and ignition coils, Cleaning fuel injectors, Adjusting engine timing, Installing new oxygen sensors It was a serious repair requiring several days of work. The engine knock was damaging the pistons, which could have led to complete engine failure if left unchecked. Engine tuning was necessary after the cleaning to prevent further detonation issues. The symptoms match your description, weak performance, smoke, and piston slap sounds. Low octane fuel can contribute, but the root cause is usually carbon deposits disrupting proper combustion. Would recommend getting it diagnosed soon, as continued pre-ignition can cause permanent engine damage. Key prevention after repair: Using high-quality fuel, Regular oil changes, Proper warm-up before heavy acceleration, Maintaining clean air filters

Thanks for sharing those details about your repair. The symptoms you described with carbon deposits and pre-ignition match what my Rainier is experiencing. Before I take it in, could you remember roughly what the total repair cost was? Curious if you had any recurring issues with cylinder heads or detonation after getting it fixed. My mechanic is suggesting a complete fuel system cleaning along with new ignition timing components, but I want to make sure I am addressing the root cause and not just treating symptoms.

Since getting my Rendezvous fixed last month, the knocking combustion issue has been completely resolved. The total repair came to 425 Euro for cleaning out the carbon deposits in the combustion chamber and related work. This included a thorough fuel system cleaning and adjusting the ignition timing. No recurring problems with engine knock or pre-ignition since the repair. The cylinder heads were inspected during service and showed no damage, which was fortunate since catching it early prevented more serious issues. The detonation was eliminated after they cleaned the combustion chamber and recalibrated everything. Your mechanic is on the right track suggesting both fuel system cleaning and ignition components. The carbon deposit removal combined with proper timing adjustment really is essential to fix the root cause. Getting it done sooner rather than later will help avoid potential damage to your engine internals.

I finally got my car fixed last week after dealing with all those knock sensor warnings and detonation issues. The repair shop did a complete fuel system cleaning, checked the cylinder heads, and adjusted the engine timing. Total cost came to around 500 Euro, which was better than expected given how bad the knocking had become. They found heavy carbon deposits in the combustion chamber, just like you mentioned. The fuel system cleaning and new ignition components made a huge difference. The engine runs so much smoother now with no more jerking or smoke during acceleration. The mechanic also recommended switching to higher octane fuel to prevent future pre-ignition problems. After the engine tuning, I can really feel the difference in performance. Glad I got it taken care of before any serious damage occurred. The investment was worth it to avoid major engine repairs down the road.