andyfanshawe said:crabbes said:Hi Andy
Regarding your post on a friend that had fault codes reading bank 2 lean, I have this appear on my dash engine light, roughly after the 3rd or 4th long run, when I use my fault cable it allows me to clear the codes.
I am now using the Shell V power fuel but codes do come back, can you advise how to rectify this please.
Z4 roadster 2004 model
Thanks Steve![]()
Hi Steve.
Sorry, only just seen this! Ooops!
Can you give me the actual fault codes?
Bank 1 and 2 lean is normally an indication of an air leak assuming fuel trims are okay above idle. Otherwise fuel delivery issue (MAP, fuel pressure etc).
One bank lean (cyls 4, 5 and 6 for you) means more diagnosis needed. If the pre cat sensor on bank 2 and the post cat sensor on bank 2 both read lean then one sensor is confirming what the other one says and more diagnosis is needed.
If the pre cat one indicates lean and the post cat is not, you have a faulty pre cat o2 sensor.
Hope this is of some help and its not too late.
Andy.
Forgot to say,....could still be an air leak though. i would smoke that intake straightaway.