what has been changed:
2024 March
6 spark plugs, Transmission Fluid change
2024 May
PCV Breather box
2024 December
Original Turbo -> Used low mileage turbo
Original Exhaust manifold -> used low milage exhaust manifold
Original catalytic converter -> IPD sport Catalytic converter
2024 May
Alternator, (Falsely Diagnosed, didn’t really need to be changed)
2025 June
Belt service with Pulleys, freewheel clutch and water pump from Aisin.
And of course I have been changing the air filters and cabin filter myself every year
Problem:
whenever the kickdown is given, or under hard acceleration, there is a weird burning smell coming into the cabin, only happens when the revs are high and the car is accelerating. It doesn’t happen if, for example traveling at 100kph/60mph at 6th gear, and then shifting down to 2nd manually but keeping the same speed while revs are stable at 5k-6k. It also doesn’t happen if I accelerate from 100kph/60mph to 200kph/120 mph locked in 6th gear (revs slowly rising), only happens when the car is actually accelerating hard with high RPMs.
Speculations
I first thought it’s something to Due with an exhaust leak which could Be heard on cold starts, fixed that. Litterly changed everything from the engine block to the exhaust, and the smell didn’t go away. Then did a belt service, saw the freewheeling clutch had leaked its internal oil out, thought now its fixed it but no. the smell still there. Recently did a oil change and sent it to a lab to find 1.7% of fuel in the oil which diluted the oil from 0w30 to 0w20 (one level dilution before 0w30, so I assume 0w20)
I have 2 speculations right now both of which are expensive but I want to choose the right option
AC Compressor: Reasoning being that its only under hard acceleration which would make me believe that as the revs rise, the belt spins faster and maybe the AC compressor doesn’t have any oil left or the compressor clutch is failing.
However, AC still blows cold and works. Also if I’m not accelerating, even with high rpm’s ( 60mph, 2nd gear rpm stable at 5-6k), there is no smell. Also the smell is apparent irrelevant of the AC. It’s there whether AC is on or off, sooo Unsure of this option
Injector problems: After the engine oil analysis, they said the 1.7% fuel in oil could be caused by short driving cycles which I do to be honest, but as I looked deeper I saw that uneven firing fuel injectors can cause weird smells as well. But I’m still unsure as there is no codes and the engine is very smooth. Also 6 fuel injectors are not cheap as well same with AC compressor.
so I’m a bit of a dead end here. Changed so many parts and still don’t know whats causing this weird smell. If you have any suggestions or recommendation, Feel free to reply.