My stock programmed Base Pulse Width Constant is 142. Scanned BLMs show from 131 to 117. Am I still shooting for a 128 BLM? Everything I've read on this site so far says to shoot for 128.
This is in a 1992 silverado 454, 7060 ECM.
It has a cam and headers, seems to run lean on the wideband. It drives ok but seeing not less than 14:1 on the wideband makes me think theres some performance to be tuned out of it.
Any suggestions?

 

yes aim for 128

here is why
your vehicle is running rich at 117 and slightly lean at 131
by adjusting your ve your car will get closer to 128.
Every time your car gets to one of the 117 cells for your blm your car will start rich and adjust down to 117 until it achieves a 14.7:1 swing on your stock o2 sensor.
by adjusting your fuel you will be giving the vehicle the RIGHT amount of fuel at the right time to get a 14.7:1 swing.

 

http://para.noid.org/~lj/PCM%20Tutorial/PCMtutorial.htm
http://www.diy-efi.org/gmecm/papers/tunetip.html#mild
These threads might help some also.

 

Is this really true? In this case I thought once the ECM learned the 117 value it remembered and used it on next startup.

Paul T.