Hello everyone so this will be my third and final time trying to solve this car. But its a 2011 Volvo XC90 3.2 Fwd, with just over 122000 miles.
The Vehicle has these codes currently and i will explain all testing done currently and my thoughts.
P0174- System to Lean(Bank 2) Stored, Pending, & Permanent
P2097- Post Cat Fuel Trim too Rich(Bank 1) Stored, Pending, & Permanent
P0430- Cat system Efficiency Below Threshold(Bank 2) Permanent
The car has gotten all 4 new cats and 4 new sensors. New OEM PCV Oil Trap. New Exhaust Bolts & Gaskets. New Ignition Coils.
The Fuel Trims for both banks are as follows:
Bank 1-
Long Term, High of -2/3 02S1- avg .960v
Short Term, High of -8/9 02S2- avg .011ma
Bank 2-
Long Term, High of 62.5 02S1- avg .035v
Short Term, High of 35.5 02S2- avg 1.050ma
Testing done so far, ive watched the fuel trims under load(3000rpm) and Bank 2 decreases by a max of 6/7% and Bank 1 decreases a max of -1/-2%.
Ive smoke tested the exhaust system have found no leaks, smoke tested the valve cover found no leaks, smoke air intake found a leak resolved rough acceleration but did no change to codes.
Have not smoked intake manifold but suspect minor vacuum leak due to the fuel trims slightly getting better under load, but my question is the car is equipped with a MAP sensor so wouldn't that make the air leak have little effect even at idle and another question if the manifold leak was significant enough wouldn't i be getting a rich code for both banks and not such high lean fuel trims on one and then rich fuel trims on the other?
My other theory is possibly a bad exhaust manifold gasket on Bank 2 due is being defective or improper installation on my end, but which would explain why im getting such high readings if there was a leak there it would be throwing off the sensor, but that doesn't explain why bank 2 is acting weird.
I though of checking the Purge Valve solenoid n inspecting it outside the car and also smoking the evap system, but if it was either one was defective in any way wouldn't i get the same code for both banks?
At this point im beginning to think it may be a timing chain issue but could that even be a possibility, would that be able to affect 2 banks in different ways at the same time?
Also this happened out of the blue the car had never had any serious issues, and one day the check engine popped at 120000ish miles for low a voltage o2 sensors and bad cats, and 2 months later here i am stuck in a pickle lol.
check for vacuum leaks
the car is equipped with a MAP sensor so wouldn't that make the air leak have little effect
air that leaks into the manifold does not go past the MAF sensor, therefore it cannot be measured.
if the manifold leak was significant enough wouldn't i be getting a rich code for both banks
No. Vacuum leak means too much air is entering, which dilutes the mixture, making it lean.
When the engine runs lean, it tries to compensate by adding more fuel. Therefore the good bank without an air leak ends up getting too much fuel, making the mixture too rich in that bank.
Okay im thinking to smoke the manifold thru the map sensor hole due to that being the easiest to remove, as well as going from there and if that fails pulling the injectors and inspecting due to it being very simple, just disconnect the fuel pump fuse and turn the car over a few time if i was told correctly, and then its 3 10mm bolts and 7 electrical connectors in total