I replaced the engine in my 06 with an 07 N52. It runs but with a bunch of error codes. Original engine ran without any codes. Replaced it due to scored cylinder wall, low compression. Takes about 3 to 5 seconds of cranking to start but runs smoothly. Many codes seem to point to a crank sensor. Also shows trans error so it only runs in 2nd gear. Replaced crank sensor with BMW official sensor. NO change. Loosened crank sensor to see if that would change anything. It ran pretty roughly with crank sensor loose so it apparently is getting a crank sensor signal. Tightened it up again, back to the same issue. Scan tool shows 2 rpm readings, both within 40 rpm of each other. Intermittently the dash tach will blip down 200 to 400 rpm at speed (2000 to 4000 rpm) I've been trying to find if there are any differences between the two model year engines but BMW dealer said all N52s are the same. Is it possible that the crank sensor gear is different between the two years so the DME and ECU are confused? 07 engine on an 06 DME / ECU?
