Hello all...
Brand new to this board and FI tinkering - I joined because of the wealth of GM fuel injection tech info here. Seems to be a lot of good knowledge.

As you all know, ECM/PROM tuning info is sorta scattered all over and requires alot of googling. I have a fundamental question:

In an ideal world (I realize it's not perfectly practical), would it be a correct goal to try and adjust the VE tables on the PROM so that the BLM would not ever vary from 128? Basically, through testing, you would predictively place the VE table such that it would know exactly what the fuel delivery state should be before the engine got to a given condition...in effect changing a general VE table to be very specific for the vehicle.

I do realize the limitations to this approach, I just want to solidify the concept in my mind...

Now for the long shot: does anyone happen to have the stock and Whipple bins and definition files for a 1994 7.4L (in a truck with 4L80e auto trans)? I don't have the equipment to read a chip yet...I was just wanting to compare and find out exactly what Whipple changed from baseline in their supercharger kit chip.

 

That in and of itself is the basics of tuning the fuel side of things. The process of tuning your BLM's to 128 is an iterative one that has to be repeated as you change other parts of the tune. The biggest effect on your VE is going to be timing.

My usual approach to tuning involves starting with a stock or mild timing table, roughing in the VE tables so that the BLM's are +/- 5. I then move on to the timing table and tune for best performance. Then it's back to the VE table for another pass to get the BLM's back in line. Once I do this routine once I'll start working on WOT stuff and if I have time or the gumption I'll try to tighten up the BLM's to +/- 2 blm. It's pretty hard to get it any closer as there are just too many variables for the BLM's to stay right on 128.

You might want to check out my "free tune" sticky at the top of the forum for a step by step walk through of the basic tuning process.

 

Welcome to the board!

You should cruise over to the DIY PROM board after you're done in TBI. You can read that for hours (or even days) and not get all the good stuff you need.

Have fun!