Stock value is 15kpa. Do you boosted guys generally leave that there or should it be adjusted higher on a boosted application? Just curious. Thanks.

Ken R.

 

I raised the BLM MAP update trigger to 60kpa on my app. (97ss 383-D1 72# Seimen Inj./ OBD2 pcm) Still running the stock pcm with my own LT1 edit ver 2.2 flash. I used a wideband DynoJet O2 sensor to tune closed loop low speed and also WOT. Eventually I had to re_cal the MAF sensor, and, I found the computer would change the BLM update and run the engine rich @ low speed WOT after learning.

So, I raised BLM_MAP update trigger to 60kpa and dropped the MAF cal 2%. This worked for me (after numerous tests), and allowed better mileage and achieved a 14.7 low speed cruze. Before, (with stock 15kpa trigger) the pcm would adjust the afr to about 12.8. Also raised the MAF HighFreq to max and locked BLM @ 1 with WOT trigger = ON. Still, the 97 obd2 pcm has a very slow AFR change response in closed loop mode with the MAF active. Hope this helps. B.