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Yes, a new MAF made a big difference in fuel trims. Much closer to zero than before, but also a lot more reactive. KFV and KCLV are still having volatile moments, but they seem considerably more stable than they were before.
Any update?
Trims normal now?
KFV?
I might pickup a fresh MAF since I'm going RR S/C over winter now.
Trims are now pretty normal - +5-7% LTFT with STFT bouncing around +/-10% depending on load and weather. Still have the tip in issue though, and the best KCLV I've seen is ~22 with 19 being more typical on 93 pump gas. I got KCLV all the way up to 27 when it was warmer by gaming it hard while going uphill riding the brakes, but it didn't stick around for too long.
I still have a new FPS and new PCV separator to install, but I'm doubtful it will help. So far it's been new PCV, new MAF, and eliminating one extension and installing a gold pinned 6" extension on the pax side. Since I had to drop the subframe for the O2 extension change, I also validated the headers were fully torqued. I also noticed some scratches in the JetHot coating where the steering shaft runs between the primary tubes. I'm not sure how they got there, but it would really be weird if there was mechanical contact causing the KFV response. I really doubt this is the case because the tune responds well to VP's fuel additive, but it was a thought I had while I was looking around with the car in the air.
Happy to report no CEL and no smell of any kind whatsoever from the tail pipes after installing PPE headers with Gesi 400cpi cats. I have factory tune, no defoulers and factory exhaust after the headers.
Surprisingly the 400cpi cats still have no markings on them either. You can however see the tighter cell spacing compared to the 200cpi cats I was shipped originally:
200cpi
400cpi
I extended the O2 sensors using extra wire and fiberglass tubing scavenged from downstream O2 sensors spliced using brass open barrel crimps and double walled heat shrink. I know it's a very expensive piece of wire but I didn't want to use dissimilar wire since learning about how sensitive the signal is on these.
I've put on about 300km of mixed city and freeway driving over a few days since the installation and not having any issues with KCLV. I did a bunch of logging before and after installation too that I'm saving for possible future reference if anyone is interested in seeing.
