Tuning AFR problem - Z31

Nistune topics specific to the 6802 cpu

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Tuning AFR problem - Z31

Post by mrdumpty » Mon May 19, 2014 3:44 am

I've been having a problem with my Z31 tune. I can't get the low RPMs lean enough while keeping the higher RPMS
rich enough. Under boost at WOT I see 11:1-12:1 AFR yet while cruising I get anywhere from 9:1 to 12:1 and it
tends to favor the rich side of that hanging out around 9:1 or 10:1. The rich spots in the low RPM part of the map in Nistune are all
set around 14:1 and the high RPM parts closer to 11:1, so the AFR does match the map in the top just not the bottom.
If I adjust the K and Latency so that it idles correctly WOT is too lean. I have had this problem ever since going to a larger
fuel injector.
86 n/a manual trans gll
86 auto engine computer with Nistune
port matched and polished 86 n/a heads & cams
Qx4 upper plenum,throttle body and TPS
all stock sensors and ignition (except TPS)
The ONLY sensors on the engine are the TPS, MAF(blow-through), CAS, Cylinder head temp, lower plenum temp, Oil pressure.
mercedes 420cc injectors
stock FPR
walbro 255lph pump wired directly to battery voltage
Turbonetics TN-500 turbo
Turbonetics Duo-35 BOV to atmosphere
Turbonetics Evolution 35mm waste gate
Innovate LC-1 (not connected to ECU to simulate narrowband, couldn't get that to work.)

I think that's all the relevant information. Current tune is attached. I am honestly no good at tuning because I am relatively new to it.
Do you guys think switching my MAF to pull-through would make a difference for the better?
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