Confused on fueling for e85 and boost

[Jciaramitaro]

This is a street driven truck lq4 forged rotating assm, s475, deka80, walbro 525 pump, 10an fuel lines, p59, flex fuel sensor, aem wideband signal being sent to pcm via ac pressure sensor wire.

Does the pcm add/interpolate fuel when in boost (Open loop) based on e85 percentage? Or does it strictly use the VE table?

Do I need to adjust my VE table to get my afr correct. Currently at 18lbs of boost, the afr is 13.7 according to the gauge.

Thank you for your time!

[5FDP]

The computer will change the stoich based on the alcohol percent in the tank, if the VE table is pretty close the fueling should always be fine and you don't need to do any major changes.

From the looks of it, you are missing some injector data. The flow rate and the min injector pulse are the only 2 tables you changed. The short pulse adder and the voltage offset table are still stock. You need to input the correct injector data for those deka80's.

Also you will struggle to be perfect with fueling using that 3 BAR OS, just the way it is when the VE table jumps 20kpa at a time. You can only get it so good. If the fuel trims aren't going nuts and your wide open throttle fueling is staying close to your commanded, just run it.

Also, your boost enrichment table is set wrong. Putting in a value less than 1.00 means you want it really lean. The boost enrichment table still works like the PE EQ ratio table, so if you want it richer than 1.180 you'd ask for something like 1.200 for a low 12's commanded AFR.

Don't forget that for speed density you need code P0103 triggered, so the MAF fail high hz needs to be set to 0hz.

[abc]

Do I need to adjust my VE table to get my afr correct.

Yes. Right now your VE table is a mess. The PE and Boost enrichment tables are mostly just a suggestion for the PCM to target based on the correct data during closed loop. During OL, the PCM doesn't have anything reporting back to it for adjustment, your VE table is the last man standing.
Oh ya, and what 5fdp said.

[Jciaramitaro]

Thank you! So my understanding is the PCM will add fuel to the ve table, an interpolated amount, based on alcohol percentage from the flex fuel sensor?

If that is so, is there a table or parameter that shows this fuel adder?

I also have tuner pro to make changes outside of hpt if needed.

I can't always run e85 unfortunately as I have to drive an hour to get it.

[blindsquirrel]

Your injector flow rate table is 'flat' (same value all the way across) like for a referenced regulator but the offset table is sloped like for returnless. Stoich as alc% changes is at [ECM] 12300.

screenshot.16-11-2024 07.31.33.png

The PE and Boost PE tables will use whichever one is the richer of the two, but 1.18 in the regular PE is way too lean still.