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Hi all
I'm having a lot of trouble with my current situation. My 2013 BMW X3 (N20 2L turbo) has a lean air code.
LTFT is +27 at idle, reduces to about +23 at 2000 RPMs.
Occasional cold start sputter, seems to shake a bit when I put it into drive but as time goes on the situation gets better.
Figured vacuum leak, so I smoke tested it.
No leaks that I could find, PCV seems good, when I have the oil cap off I feel vacuum. Smoke fills the crankcase, don't know if thats normal. Would a ~30% LTFT be a tiny tiny leak id have trouble finding or should it be pretty significant?
That said, the boost gauge shows -2psi at idle.
MAF was cleaned, shows 3 g/s idle.
A/F reads 1.03, post cat O2 seems slightly responsive but maintains 0.7V at idle.
HP Fuel rail pressure is around 900 psi, when I increase throttle it goes up to about 1200 temporarily then normalizes.
My intake air temperature currently reads 65F, it's 34F right now and the engine is cold, ambient sensor reads correctly, but in a freeze frame from earlier the ambient shows 105F. I assume this is explained by the under the hood temp being measured, though it is cause for concern... Could this be it?
Any ideas? Thank you
Figured i'd update the post since I found out my solution.
It's the fuel injectors. This was an engine replacement, 2013 N20 to a 2017 N20. Old engine and computer ran EU5 injectors. New engine has the old ECU on it with new engine injectors that are EU6. The spray pattern/direction of the injectors is slightly different, EU6 points a bit less in the direction of the exhaust. Calibration of new injectors via ISTA will not fix an EU5 ECU to work with EU6 injectors.
BMW parts department claims if you replace all injectors with EU6, you will be fine, which is not correct.
So yeah, half ECU, half injectors. Their incompatibility was the issue.
