Hello everyone, I’m having a small issue with idling and exhaust rumbling. When I crank the car, the car will crank very nicely, like OEM, but will overshoot the target idle RPM. I currently have target idle rpm offset disabled, meaning that 1000 rpm is 1000 rpm being targeted. I’ll post a few logs below on what’s happening, but the rpm will overshoot (say 1400 rpm), but then drop right back down to 500, before struggling to make it’s way back up to target idle (say 1000 rpm); over the course of about 30 seconds.
I noticed that in the log, ramp down is active when the rpm drops significantly, but I can’t figure out why that is intervening with my cranking / idle strategy. Maybe it has to do with the car wanting to overshoot target idle rpm so much?
Additionally, my exhaust has a rumbling sound, almost like small turbo charger pops and bangs on downshift or deceleration. I’ll also post a small video of the exhaust note, as it’s super noticeable and sounds more like misfire. It used to sound like that before, then went away, but then has now come back. Can confirm that injectors and coil plugs are good and fire correctly, in the correct firing order. Is this a tuning related issue? If so, any insight on what I can try to resolve this for good? Just want to confirm before purchasing new injectors, spark plugs, and coil plugs as a possible remedy.
I’ll also supply my project file, so no time is wasted, really hope someone can offer some insight on what’s wrong. Car is a BMW N55 GDI engine, stock cams and internals, with retrofitted electronic wastegate over from the pneumatic.
Videos: (Google Drive, Preview Without Download)
Downloads:
BMW 135I ECU.emupro (35.9 KB)
support 2.emuprolog (609.6 KB)
support.emuprolog (2.3 MB)