Currently using EBL FLash on my 89 IROC. I found an issue with my tune where my VE tables at low (80-100) kpa are maxed out at 100% but my AFR at WOT is still lean. I see a couple of methods to correct it and they both have there problems.

First, the BPC-BPC vs vac table allows me to raise the BPC and lower the AFR. Problem here is the vac is low (0-10) at times other than WOT. It worked but cause rich conditions at other times.

The other is to change the PE WOT tables to a lower AFR. I don't care for this because they are now at my target AFR (12.8) and I'd like to keep them "accurate" if possible.

Maybe there's a way I haven't discovered. Any direction is appreciated.

BTW I really like this system and it has been a easy transition from burning chips with the stock ECM.

 

Have you made certain you have the correct Injector Bias values altho this will have a smaller impact at WOT. WHAT's your Injector Duty Cycle at WOT?

 

Correct? I used the IO Bob published for the injectors I'm using, so I'd say yes.

Duty cycle after changing the BPC-BPC vs vac to get the WOT AFR in the 12.9-13.3 range is <85% so I should be good there. Not hitting the limit by any means.

Changing the BPC vs vac does correct the WOT fuel but made it too rich at some high load- low to mid rpm ranges. I'm trying some other values in this table to see if I can get the WOT AFR right without affecting the other areas as much.

Thanks for the input Dom.

 

With TPI (multi-port) the "BPC-BPC vs VAC" table needs to have the same value throughout. As you increased this BPC table, the VE table needs to be reduced by the same percentage.

This gets the low and mid range back in line and provides more head room in the VE table.

Think of the BPC table as more of a centering device for the VE table(s).

RBob.

 

Awww that makes a lot of sense. So by raising the BPC vs vac table I am in sense enrichening the whole ve table. Most of the ve tuning has subtracted fuel from the base bin so I'll be subtracting more after changing the BPC vs vac.

If the BPC is calculated from actual engine CI and injector size and I raise it then I am basically saying my engine is larger or my injectors are smaller. Does this "tell us" anything about my overall combination? Is it "more or less" efficient than it theoretically should be?

 

Also, in regard to the % changes to the BPC and VE tables. For example, currently my BPC is 141. If I change the BPC to 150 to get my WOT fueling in line, should I take that % (141/150=.94) and multiply the entire VE table x .94?

 

Should be a good starting point.