Here we go again! Car is off to the shop because this one is beyond me. Started getting some new symptoms last week:
- Rev hunting
- Lurching on constant throttle
- Loud and variable DV noise on constant throttle with VERY inconsistent throttle response
- Low/no boost and finally hit limp mode over the weekend
- Car stalling on stops
- Engine malfunction warning with reduced engine power following
Codes:
2e0f - Valvetronic system: disabled, too frequent (???)
29d0 - Intake air temperature sensor, electrical: Short circuit to B+
2c57 - Reduced power mode / Boost disabled
2775 - Airmass too low - Possible boost leak
2c90 - Blow-off valve, mechanics: Jammed closed (Tuner code, disregard)
3166 - Tank safety valve: malfunction (Tuner code on N55/JB4, disregard)
These issues have been present in Map 1, Map 5, AND Map 0 (jb4 "off").
UPDATE - This has been resolved and was due to a few issues combined, I'll try to include them all here for future reference if anyone else has similar problems.
Issue number one: Car was in need of a DME update which was causing the valvetronic malfunction, IAT issue, and 29d0 and 2e0f codes. TSB info on this below:
TSB: BMW SI B12 36 15
Which (in no short terms) covers Valvetronic system and "air mass plausibility" faults, among others.
The fix is a DME update and mechanical repairs if needed (if the power surges caused damage). Thankfully I did not need any mechanical repairs and the guys were kind enough not to charge me diag. So a $200 software update plus a night without Tobias and I'm back on the road as of today. The ride home definitely felt smoother but the real test will be cold starts and more seat time. Another part of the fix is listed below regarding a fuel tank vent valve.
Hope this thread might help someone in the future, the TSB also applies to the N20 and N26. Some other codes that may display are:
E-series with BN2000:
2775 - Air Mass, plausibility: Air mass too low
2c57 - Charging pressure control, plausibility: Pressure too low
2dce - Valvetronic System: No adjustment possible
3164 - Fuel tank ventilation system, 2nd inlet point: Malfunction
F-series with BN2020:
102002 - Air Mass, plausibility: Air mass too low
120308 - Charging pressure control, plausibility: Pressure too low
133b04 - Valvetronic System: No adjustment possible
191c02 - Fuel tank ventilation system, 2nd inlet point: Malfunction
Route cause of the issue is a defective valvetronic or tank ventilation component/Erroneous faults set due to DME software parameters.
Funny thing is the BMW dealership saw these codes and replaced the tank ventilation component back when my water pump died, if you look at that thread you can see it listed on the receipt the invoice I posted.
Issue number two:
Bad firmware on JB4 + bad spark plugs/coils - symptoms were engine malfunction, boost inconsistencies, and other codes. This was resolved quickly and easily by speaking with Terry and Jon at Burger tuning who provided me with a firmware update that seems to have solved my overboost/peakiness issues completely.
I also installed Burger's listed NGK 1-Step colder spark plugs, as well as new coils, just to be safe. I did not have any listed missfires but this should ensure a clean and accurate burn from now on.
Issue number three:
Flex Fuel or "FF" harness for JB4 was not connected. On the Burger tuning site it says this harness is OPTIONAL. However after some digging I discovered that even if you do not plan to run ethanol you should connect this harness. Symptoms from this being left disconnected include throttle response and stalling.
Testing & Validation:
I've now been running the car for a week with the JB4 in and all of the above repairs in place. I have not had any further engine malfunctions or codes other than the typical JB4 tuner codes and the valve code for having the muffler flap blocked (golf tee mod). Additionally, there is no further sign of any of the symptoms listed above. The throttle response isn't completely flat, nor is the power curve, but that is expected with the JB4/any piggyback tune.
I've also run quite a few logs on the JB4 and have not seen any issues with under/overboosting - actual boost is consistently within +/- 1 PSI of target, which is in spec. The only thing I've been noticing is some leaning out at certain times, which is typical of the JB4/any N55 tune, but I will be watching this and keeping an eye out for any fuel pump errors.
TL;DR - everything is fixed after the above repairs and no issues have returned so far. Hope this helps someone in the future!