Rich @ Idle but No CEL

*Email out to tuner and checked other forums, but needing help*

Looks like I'm trending 14.2-14.5 AFR at idle. LTFT at idle is +9.x. I'm used to seeing 14.7-14.8 after the ECU does it's hunting/making sure the primary 02 is working thing. But that's usually not occurring when sitting at idle continuously, but slowing down to a stop light, etc.

No CELs. It could be a vacuum leak, adding unmetered extra air that my idle LTFT has to go positive to fix. Or it could be a potential exhaust leak, maybe the DP flange area, because any leak pre-IM should cause lean at idle because everything is under vacuum at idle. Logs attached.

Thoughts?

 

Has anything changed recently that could've caused this or did you just recently notice this because of a weird idle or something?

 

Nope. Just normal wear and tear. Tightened up intake and FMIC couplers. put a new MAF o-ring on, cleaned the MAF, and did a few MAF cal revisions (my 93 tune is one of the last unlocked ones before Justin switched over to locking all maps). Voila, I'm in the +/- 3 LTFT range across all breakpoints again.

 

Update: after pondering this a while and pretty much ruling out any mechanical issues (due to my 93 LTFTs all being on point), I just asked Justin to update my idle breakpoint range MAF cal. I had to toss him $20 anyways to get an EGR-enabled map for inspection this month. He was gracious enough to throw in the slight MAF adjustment as a freebie. Looks like my E28 map LTFTs are all within +/- 5 now