help diagnosing why I'm running lean at idle? B230ft w/ 16t

Just about finished a build.

- fresh b230ft
- ported 90 manifold
- 16t
- 3in DP
- Yoshifab catch can
- new green top injectors
- Sbabbs chipped lh2.2 ecu
- AW71 accumulator mod

Wanted to install the NPR intercooler and street cam but I want to fix this issue first

When the car is cold started, it's reads 14.7 on the wideband and then creeps up and eventually just runs rich. This only happens when idling. Any ideas why? While cruising it's fine at 14.1- 14.8 and never gives me a problem. Under boost it may briefly run lean at 10.6 for a split second then flattens out at 11.2 and stays around there.

Why is it only running rich at idle? I can't figure it out. From all of the countless threads I've read before, this shouldn't be a problem with a simple turbo swap of this mild caliber. Many have done it before. Am I missing something?

Looks like you got it reversed?
Numbers below 14.7 mean rich, anything above lean.

Your numbers under boost are pretty much similar to the ones I see on my LH 2.4 230FT w./ 16T (chips by TLAO). Looks fine to me.
As for the idle, not sure about that, it doesn't lean out that much on my setup.

Does it run rich at idle after warmed up?

IIRC when I had LH2.2 turbo a cold start would read 14.7 on the wideband initially and then richened up to ~12 until the car warmed up. Hot idle bounced around 14.7.

Your description of AFR under boost is exactly what I experienced and very typical.

oldschoolvolvo said:

Does it run rich at idle after warmed up?

IIRC when I had LH2.2 turbo a cold start would read 14.7 on the wideband initially and then richened up to ~12 until the car warmed up. Hot idle bounced around 14.7.

Your description of AFR under boost is exactly what I experienced and very typical.

Click to expand...

Yea, it will run rich after warmed up on idle. I was able to tweak a few things and got it sitting around 15.7 on idle now. If it's pretty common then I'll leave it at that and call it a day

You can adjust the AMM screw using an analogue dwell meter on lh2.2 to monitor where you want to set it. Have you messed with that at all?

oldschoolvolvo said:

Does it run rich at idle after warmed up?

IIRC when I had LH2.2 turbo a cold start would read 14.7 on the wideband initially and then richened up to ~12 until the car warmed up. Hot idle bounced around 14.7.

Your description of AFR under boost is exactly what I experienced and very typical.

Click to expand...

Should be this. Anything other than this, with the exception of running richer under boost isn't right... Should run at stoich when under load as well, yet not in boost. Lean out to full lean on decel

Try adjusting the air mass meter to have the 14.7 idle mixture. The rest of your readings seem ok to me as well. 15.7 is too lean at idle though.