The patient is my 2018 xc90 Spa platform T6 with 84k km on odo.
had some issues with missifires, changed sparkplugs, switched coils(to see if missfire related) replaced the injectors, reseted the fuel trims adaptations with launch x431 for a while it was fine – BUT – after a 10kkm i keep getting cat efficiency error, evap error, and the most weird thing was that the compressor boosts up to 3500rpm, then when accelerating there’s a slight single jerk, and lack of power – like the turbo does not kick in at all. other than that the cars starts fine, drives fine except that sudden loss of power at 3500rpm,
did a smoke test, found a leak at the oil inlet, replaced it, no leaks except that, did a smoke test with evap, didn’t find any leaks there, checked the evap valve with external power and smoke. it kicks in and cuts of nicely. evap lines intact.
i’ve replaced the intake and compressor seals, now ordered a bank1 o2 sensor since when using basic carscanner STFT look weird – they’re generally around 0-5% but sometimes drop -90% for a second then they’re back this goes parralel with o2 sensor read so that’s my next guess.
i don’t think cat is killed with 85k km since i’ve diven this car since it had 50kkm on the odometer, 8k km oil changes, along with all the filters, generally car well treated.
to the more experienced volvo users – is there anything else i should try? Are there any other reasons my turbo is castrated at 3500rpm? is there some other things i should check, before/after replacing the front o2 sensor?
thanks! i’ll post some pictures of the cat when i replace the front o2 sensor next week.
forgot to mention, the pressure valve checked out fine, volvo part 31480559, the vacuum lines are not bent, cracked or have leaks, the membrane turbo vacuum actuator looks and feels mechanically fine and mechanically moves. we even tried to short connect the vacuum directly with bypassing the valve to see whether the turbo would work – it wouldn’t
i can provide more data or graphs if needed but please guide me to which one are needed, i have icar vgate and carscanner app, it’s a budget option, but can provide some data.
trying to narrow down everything here. but it’s a tough one. (btw, ignore the misfire message – it’s an LPG related thing, and this is soon going to be resolved, but it does not affect the power loss.)
