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Would this be enough to cause high fuel trim? (pic)
Been struggling with high fuel trims (+25%) on bank 2 and have been looking for a vacuum or exhaust leak. Was under the car tonight and saw a gap on the bank 2 side where the header flange meets the block. That can't be good. So,
1. Would this be enough to cause a high long term fuel trim at idle?
it's hard to tell from the picture what's going on there, i don't see any carbon pushing out of that hole, so are you sure that's really an exhaust leak? you'd figure if it was you'd hear that pretty obviously too.
That isn't a hole, it is just the thin machined edge that the flange butts up to. See what I circled in the pic. You would have to have one hell of a warped flange/missing gasket/backed out header bolts to cause a leak there and like the other guy said there would be carbon deposits surrounding it.
I don't know...I'll have to check. Could that cause only one bank to run lean?
What open throttle blades will do is cause the IAC (Idle Air Control) that feeds each intake runner to close off and the most common result is referred to as "split BLMs" (your problem). Unmodified aftermarket throttle bodies are known to cause this but not so much stock ones unless it is really gross inside. Search "split BLM" and you will find more than you care to know on the subject.
Ok, checked out TB blades tonight and they look closed to me. Granted. I don't know exactly what I'm looking at!
Originally Posted by stevo9389
What open throttle blades will do is cause the IAC (Idle Air Control) that feeds each intake runner to close off and the most common result is referred to as "split BLMs" (your problem). Unmodified aftermarket throttle bodies are known to cause this but not so much stock ones unless it is really gross inside. Search "split BLM" and you will find more than you care to know on the subject.
04-11-2016, 07:39 PM
Would this be enough to cause high fuel trim? (pic) 
