[relative4]

'08 335xi, 74K miles, stage 1+. New ignition coils as of 3 weeks ago, spark plugs have about 9K miles, injectors & HPFP have about 40K miles. Did a track day 2 weeks ago, performed great.
This morning I was on a Starbucks run, and it started stumbling and popped the SES light. Got home, plugged in MHD, and got misfires on cylinders 1 and 2. I pulled a log at idle. Bank 2 lambda is steady at 16; bank 1 lambda is all over the place from 20 to 28. With the car still idling, I plugged in ISTA. While that was firing up, the stumbling got worse, and the car started to stink pretty bad. ISTA reported misfires on cylinders 1 through 3, the SES started flashing, and I shut it down.
Maybe my Starbucks hasn't kicked in; I feel like with a sudden onset on an entire bank like this, the answer should be obvious, but I'm drawing a blank. Doesn't seem like a vacuum leak, a HPFP would affect both banks, and plug/coil/injector wouldn't hit an entire bank like this.
An upper O2 sensor wouldn't cause misfires like this, would it? There are no codes for a sensor.

Here's the log. Thanks for any ideas.
https://datazap.me/u/billyandrewsv8m...&data=14-15-20

29CC DME: Combustion misfires, several cylinders
29CD DME: Combustion misfires, cylinder 1
29CE DME: Combustion misfires, cylinder 2
29CF DME: Combustion misfires, cylinder 3

[_N54]

Possibly a mosfet?

[Soden82]

Originally Posted by ///S58

Possibly a mosfet?

I agree, seems like the whole bank is down for the count

[mweisdorfer]

Originally Posted by ///S58

Possibly a mosfet?

Update your Mosfets, if you have the MSD80 DME. If that doesn't fix it, then you have to get a new DME. In such case, I'd upgrade to the MSD81. There are places you can send in your old DME, CAS module & one key. They will update the CAS with the new DME & your Key. Probably cost $500.00 or so

[relative4]

Bad MOSFETs don't always throw a 30BB?

[_N54]

Originally Posted by relative4

Bad MOSFETs don't always throw a 30BB?

Maybe, but i would think if all banks were misfiring it would throw 30BB. Just have it tested so you can rule it out.

[relative4]

I pulled the DME and tested the MOSFETs, they're all fine. What next?

[relative4]

Part out, I guess.

[_N54]

Check your spark plugs on cylinder 1-3 when it sits overnight and see if any are fouled or wet.

[_N54]

Also, try to load test your battery. It's common for a weak battery to cause misfires.

[relative4]

Turns out my history was not 100% accurate. When the HPFP and injectors were changed in 2012 with 34K miles, only 4 of them were replaced (with index 9). Cylinders 2 and 6 are still rocking index 5 injectors. I suspect injector 2 is dying, but that doesn't explain the misfires on cylinders 1 and 3.
I triple-checked all MOSFETs, reinstalled the DME, swapped all coils from one bank to the other, warmed the car up for a long time, and drove it. The bank 1 LTFT is still way high at 22%, but not pegged. The car still idles a little rough, but no codes are thrown, and the lambda is no longer all over the place. Oh good, intermittent problems are way more fun to track down.

I don't see entries for cylinder roughness in MHD's logging tool. What tools do you guys like to use to monitor cylinder roughness?

[feuer]

Originally Posted by relative4

I pulled the DME and tested the MOSFETs, they're all fine. What next?

Of course, or would have shown 30ba. 30bb is for bank 2 I think. If I’m to guess i is either your tune or o2 sensors.

In inpa delete all adaptations and perform rough cylinder synchronization.

I have 6 x index 7 and 2 x index 1 for sale.