Hi everyone,

I have a 2008 535i that is stock for the most part besides DCI, muffler delete, and MHD flash (currently on stock map). I had the JB4 previously but ran into some issues with CEL so it was removed and MHD added for monitoring and flashing. I am running into some issues with a 30FF and also O2 issues which all started getting worse after running 50/50 E85 for about 2-3 months, I got CEL for 3 out of 4 O2 and had all 4 of them replaced. I am running 91 now and starts and runs fine, (sometime it will idle rough for a few seconds after cold start) and has plenty of power off the line. I will get a reduced power warning about 4-5k RPM if I am WOT. Here are the codes I get after clearing everything and driving around the block mostly WOT.

2C3E Oxygen Sensor 2 before cat - line fault
2CA7 O2 Sensor Heater cat - function
2CAB O2 Sensor before cat - tempature
2E8E Intelligent battery sensor missing
2FA3 No Coding
30FF Turbocharger pressure too low

Recent repairs:
Walnut Blasting, Ignition Coils, Plugs, 4x O2 Sensors

 

i get 30ff as well but i dont have all those errors. id clear the codes and see what comes back as start.

 

These codes are after driving the car for about 5 minutes. Are you saying reset and don't drive it at all, just idle until codes come?

 

It looks like you have either a vacuum leak, leaking injector or faulty sensors. Were these OE sensors or OEM. More than likely there is leak some where and your sensors were never bad to begin with.

 

I am in complete agreement here. Your first priority is to figure out why boost is too low and vacuum is nbr one thing to check out.

 

The replacement sensors are all Bosch, I saw a post about doing a pressure test to check for leaks and can do that this weekend. How would I test for a leaking injector? Wouldn't that cause a misfire if it was just one injector?

 

Not necessarily. A failed injector would cause one a leaking injector would cause fuel not to be ignited causing an O2 fault. Check for vacuum first. Then move to injectors. I'm sure vacuum is your issue.

 

i thought the 30ff code was a sign that the waste gates were leaking. time to replace the turbos.


G~

 

There are many reasons for an underboost diagnostic code. Needing new turbos is the least likely.

 

Here is a log from rolling about 40 in 3rd gear, WOT until around 65 when I got reduced power warning. I noticed that bank 2 is running in the 30's compared to bank 1 being around 14

Click Here: Data Log