[sbonomo]

I have 2009 135M with the JB4 installed. I recently replaced the #5 injector due to rough idling and cold starts. The car works fine now in either JB4 disabled or OEM stock tune. When i put on either the 13 lbs of boost or progressive mode it throws a code that the number 2 injector is bad. Has anyone else experienced this? I love the added power and ability to change modes but this is becoming to too much of a pain.

[Steve @ BMS/Fuel-It!]

That's not a JB4 issue. That's a hardware issue from pushing more boost/performance which results in more stress on components and will expose those weaknesses.

[sbonomo]

Originally Posted by Steve @ BMS/Fuel-It!

That's not a JB4 issue. That's a hardware issue from pushing more boost/performance which results in more stress on components and will expose those weaknesses.

Thank you for the quick reply. I have just started doing research on possible fixes. the consensus seems to be to replace all of the injectors (or at least the entire bank that is failing) right?

[Steve @ BMS/Fuel-It!]

Correct...or swap injectors to verify the problem follows. If running the new index 12 injectors, then yes, they all need to be index 12 for that bank or you could replace all of them but since you've replaced 1 already, then you'll want to verify what index it is and proceed accordingly.