silverado 3bar SD OS, BE not holding

[ToxicWS6]

ive recently swapped ls3 heads and LSA blower onto my lq4 with a stg1 blower cam and put in a 3 bar SD OS using the stock LSA map and injectors with fuel lab boost referenced FPR, all is going well so far, (still a rough tune but) issue im having now ive never seen or had when previously tuning my turbo trans am is in the BE table i command 11.8 AFR and in my car i get basically 11.8 no questions asked as soon as i see postive pressure, well in my silverado i have it set so 110kpa and up should be 11.8 AFR for now just to get everything roughed in, well issue im having is if im 1/3 or 3/4 into the throttle and im at any sort of postive pressure 3psi to my max 9psi it will drop right down to 11.5-11.8 AFR like normal but then as the rpms go up the AFR just goes up with it, around 3600rpms im at 12.4ish and then by the time im at 4800rpms im at like 14.0+ AFR while still 110KPA+ and usually WOT, so i end up letting out.

that being said im 99% sure its not fuel system related as this first indicated my fuel pump couldn't keep up (experienced this in my car before fuel upgrade) that being said im running 320lph AEM pump, -8 feed lines and -6 return going into stock LSA fuel rails so i highly doubt im running out of fuel, also what makes me think its more tune related is i layed into it once and the locker in the rear didnt engage so i ended up blowing the tire off through 1st for awhile, only reason i stayed in it is my AFR stayed happily at around 11.X the whole 3-5 secs at 55XX+RPMs and everything else was good and happy, it also held good AFR on another WOT pull out of no were.

what else can effect AFR that i may have forgotten about or missed, i always assumed BE trumped everything else and when it met all its set points it did its thing and commanded your set AFR, mine being 11.8.

thanks!

[5FDP]

Your VE table is the "fueling" table, if that has not been tuned that is going to be a problem.

If you removed the MAF and have it failed correctly, the VE table is where you make changes.

Post the tune.

[ToxicWS6]

3 bar OS Tune 2.6 ve,spark.hpt

again i just started this so its deff not 100% but here it is

[5FDP]

On that tune, a few things worth changing.

Because you aren't running a MAF, you need to set the 3 MAF dtc's to first error and just uncheck the SES boxes if you don't want the light on.

Under power enrichment, there is still a 60.0 second time delay for PE and a 5,500 rpm delay. Set the time delay to zero and the rpm to something like 2,000 rpm. You also disabled the engine side TM, so lower the enable torque percent from 100% to 80%. Throttle pedal enable is still at 90%, which is fine but you may want it lower like 60-70% depending on your wants and wanting fuel when boost comes on.

I didn't see much that stood out and was way wrong or anything so I guess start tuning your VE table with a wideband and go from there. Also it does kinda suck that your VE table has terrible resolution only going up by 20 kpa each time. I bet if a 2 bar OS was an option on that computer it would suite this combo better if you aren't running over 14 psi of boost because most 2 bar OS's run up by 5 kpa and 10 kpa on the row axis making it eaiser to fine tune them. You'd also have to get a new 2 bar map though.

[ToxicWS6]

i thought i had maf codes set right but ill deff recheck them, and ok cool deal on the PE info, i know nothing on it as i tuned purely off BE on my turbo car, and yeah, i think i might take this 3 bar map sensor and swap it for my 2 bar map sensor on my trans am and put the truck as a 2 bar OS, also get RTT too, and then 3 bar on my car as my car will see higher boost then my truck. trucks gunna be a fun DD so the stock 9psi im perfectly happy with, car is fun weekend/road race car.

[ToxicWS6]

yeah my maf codes where deff wrong...lol, and i did the above changes so ill do some pulls tomm and see how it goes and post the info, thanks!!

[5FDP]

If things are still slightly off even with those changes, just remember the VE table will still need work.

Raping the PE or BE to get your desired WOT afr is not the right way to do. If kind of one of those set it and forget it tables. Have a commanded AFR but use the VE to bring in fuel or remove fuel.

[ToxicWS6]

so i should up the VE table in the areas im leaning out in to get correct fuel and not just trust the PE or BE

[5FDP]

Yes. PE and BE are not meant for changing AFR. They are just tables to set a commanded AFR under PE/boost.

If you were lean you would not just add more fuel to PE, that is not even close to right way to do it.


Ideally you should have scaled your VE table from the get go. If you do switch your OS to a 2 bar to give yourself a better VE. You'd copy over the 0-100kpa values then at say 200kpa you'd put like 180 and interpolate downwards to build yourself a VE for boost. Then tuning everything from there. That where using your wideband error can correct the table and make it smooth.

[ToxicWS6]

so i played with the PE and re did my VE table and its all a lot better, feel safe driving it now so i can start focusing on the VE table mainly as u said it needs more work, thanks!