e40 lean on part throttle for a short time

[Gummisko]

after deacceleration i get it most often but some times from coast and i push thottle a little bit and widebandAFR goes beyond 19 for a short while and looses power, before it wakes up and goes normally... i have caught it a few time in the logs, o2 goes to below 20mV, (last few accel in the smallest log easiest to find)
but i have an mpvi without external 5v so i cant log wideband

i tried to tune out dfco, i dont know if i succeeded.

i dont know what to change in the transiet tables or if the will make a difference.


its a e40 ecm with ls2 intake and ls2 injectors on a LS1 block
summit stage 4 cam
+3cc pistons 1od, eagle rods
LT headers dual 3" into dual 2.5" at the end
drysump system

[blindsquirrel]

Feels like a misfire, almost like a 2-step? If it is, the misfire could be either the cause of the lean readings, or a lean condition could be causing misfires. It's really difficult to pin down which is causing which when that happens.

PE is still 100% stock, might work on that a bit. Get rid of the below-5000 RPM delay, raise enable MAP to around 65 or 70kPa. Let it go a bit richer at lower RPM in the EQ table.

I know it's in areas of the spark map that really should never get used, but high octane spark is lower than low octane. And everywhere from 1200-up they are identical.

VE is still GTO 6.0L stock except for the 400-800 RPM rows... does it behave better in MAF-only?

[Gummisko]

I am on only MAF.

In open loop the problem dissapears...

[blindsquirrel]

screenshot.27-04-2022 11.46.10.png

Those are the stock settings for blended MAF-VE. MAF-only has to have very low numbers there. Disable = 200, re-enable = 150.

So with your current settings it's still using VE below 3600, and the VE is still stock for a 6.0L, and you don't have a 6.0l anymore.

[Gummisko]

thanks for pointing us to the right direction.

we failed out the maf and tuned the ve, now it works like a charm!

400whp 510wnm

(my timeattack class allows a maximum of 450 hp att the flywheel)