what controls bpw at start up, $A1?

[Superdave]

Little high, I know other 3x00 tunes that go lower than 150 but it's always worked well for me on stock engines with both 22.5 and 24lb/hr injectors.


What can happen is that when tuning WOT it's possible to max out the VE tables yet still not be able to deliver enough fuel when the injectors are actually large enough to do so. That's why it's important to get the BPC set to a value that works with the size of injectors you have. That will give you a good range in the VE tables.

[robertisaar]

as i've explained on the gearhead-EFI forums, the BPC is really just a multiplier, a pretty fudged one at that. you want to set it so that you will get as close as possible, but not exceed 100% VE. that will give the best resolution without limiting anything.

unfortunately, it will have the side effect of AFRs other than stoich not necessarily being correct.....

[LZeppelin513]

I am finding that I need to increase my combined main VE over 100. Is that OK? Can the main VE be below 100 plus adder making the total over 100?

[robertisaar]

the two tables are added together and limited to 100. well, not so much limited as much as it's the extent of the 8 bit range.

[Superdave]

What is your exact engine combination?

[LZeppelin513]

2005 3500 from Malibu i think, CAI to lx5 TB, 2" OD true dual exhaust. New HRE high flow fuel pump and Areomotive FPR. Pretty basic set up.

I am leaned out at WOT to 14:1 at 4000 RPM with PE AFR set to 12.6. I could either adjust PE AFR down to compensate or up the VE table. VE at 4000 rpm and 100 kpa is 98 now. In closed loop 98 at this rpm and 100 kpa would make AFR probably very close to 14.7:1. For some reason PE AFR is not dumping enough fuel.

I don't think its a fuel pump issue as I have seen much richer conditions at this RPM in my tuning trials over the last several months.

[LZeppelin513]

Oh and I recently set BPC to 150 down from 168. This latest report is with an updated VE table with respect to an updated BPC of 150