12200411 - A Few General Questions

[ezobens]

I ran into the same issue when I retrofit a 12200411 PCM to my 455 Pontiac. The problem was that the VE table I started with was far too low for my application. The 411 uses a VE table whose entries are proportional to engine displacement, so if your engine is much larger in displacement than the stock calibration you started with, you will need to scale the VE table accordingly, just to get in the ballpark. In my case, the finished VE table for my 455 was nearly 2x that of the L31 calibration I started with in the idle/low load areas that you'd be using when transitioning from startup fueling to the VE table. This meant that before I made the correction, as the PCM transitioned from cranking fueling to run fueling, it would be VERY lean and would stall. -Scott

I have not touched the VE tables and am currently using the stock LS1 Corvette table- How do you know where and how much to adjust? Is it more trial and error or is there a methodology? Thanks! Elm

[ScottP]

To start with, you could scale the VE table by the ratio of your engine's displacement (409ci) to the stockLS1 (346ci) whose VE table you used, so in this case, x1.182.Once its running, you'll need to datalog your trims to begin fine tuning the VE table. Both EFILive andHPTuners have excellent logging utilities that bin your trims into the same cell structure as the VE table.

[ezobens]

To start with, you could scale the VE table by the ratio of your engine's displacement (409ci) to the stockLS1 (346ci) whose VE table you used, so in this case, x1.182.Once its running, you'll need to datalog your trims to begin fine tuning the VE table. Both EFILive andHPTuners have excellent logging utilities that bin your trims into the same cell structure as the VE table.

Do I want to modify just the 'Main VE' table or also the 'VE While Cranking' table (EFILive)? Thanks! Elm