Hey guys, I have a magnacharged 6.0 and have an issue with a lean surge right after transition into WOT. The ECM is commanding my PE AFR of 11.8, however according to the wideband it leans out extremely quickly when entering boost. It is very noticeable to me as well so I know its not a wideband output issue. The car drives like a charm at part throttle, no matter what throttle % as long as its not in boost. Once 101 KPA is reached, it commands my PE ratio and falls on its face, leaning out, sometimes as high as 19.9:1. This has got me stumped. Here is a log and my tune, if anyone can help me that would be awesome.

the lean spike in question is in frame 605

 

Something that helps to make sure that you enter PE Mode instantly is I always set everything in PE Enable to all 0s.

MAP 0

MAP Hyst 0

Delay RPM 0

Enable Torque 0

Torque Hyst 0

I also noticed the huge dip in your MAF table! You want the MAF table nice and smooth, a few tiny bumps are fine but not large transitions like mountain ranges.

 

Also was I seeing that right that you are logging like 46-48 bytes in the table? The more PIDs you have in there the less frames per second of good data it will gather.

Generally you dont want to exceed 24 bytes.

Do you ever see the AFR you are commanding at WOT or is it just a momentary lean spike?

 

I will adjust all my PE enables down, and remove some of the PIDs.

I have not seen the commanded PE ratio yet, of course at 19.9:1 I am not in the throttle for long so I do not know if it will recover.

Earlier this afternoon, after the post I made, I went out and stabbed it at about 15mph, it went to 88% TPS and leaned WAY out, my wideband stopped at 20:1 and the car almost died, so until I get this issue sorted I do not want to push it so hard.

 

Up your enrichment rate, this won't make to much of a difference but it will help your pcm get to commanded quicker.

Your PE enable TPS table is a tad passive as you go past 3K rpm. Get it down to 30% QUICK.

on your enable tables...eh, I don't think any of those pose a problem for keeping you lean on a stab IMHO.

Smooth out those spark transitions. I like the aggressive hit on the initial g/cyl max hit you got set up there though. Looks like mine. LOL.

and what klug's says, holy scary maf table. You essentially are telling the computer as it goes over that dip that you have that much less air, hence much less fuel. That should fix alot right there.

After that, everybody has lean spikes on the roots blowers. It just lots of air real quick. If you had transient fuel tables in your tune you could kill alot of it but you don't. After that, you need to learn your way around your VE table. Figuring out the best place to "swell" the VE to soak the "hit". Try to find a spot you normally aren't in while driving normal and making normal throttle transitions, only the area of fast foot transition. 1bar is tough with the radix. It loves to put you in the 100kpa zone a lot, thus wasting tons of fuel when you aren't trying to floor it.

If it doesn't stumble or sputter and only lasts literally a split second or less, don't sweat it too much IMO. Yours is too much, but just want to warn you, you may never really get rid of it. And if you do...post up, lots of maggy owners will want to know what you did exactly.

 

Dewmanshu, I read your thread on transient fueling tables. Here's the kicker on my situation, my set up is a 2002 essentially, but the operating system and engine are a 2003. The reason being is I eliminated DBW and had to go back in time with my ECM to get the IAC drivers, so a 2002 computer has a 2003 cal in it. Is not having transient controls an issue?

 

I'd do what Klugs' SS wrote.

Maf needs works,and the PE enrichment tables need to be addressed.I'm sure it's causing a delay when you hammer it.

 

The VE table is very important in transitional areas like that, so you might want to spend some more time there.

 

Made some changes, still no go, lean all the time, the commanded AFR is 11.8 for PE, AFR fluctuates from 17-20:1. I'm nervous guys, I don't like keeping my foot in it that lean, even for experimenting.

Can someone explain how to optimize my VE for the blower, I'm not to versed in tuning yet. I am better at sticking LSx's in places they are not supposed to rather than tuning them

 

WOW! Uhm...you have more than just a stock in tank pump right? Fuel pressure? No way should it go lean like that once you creep it over 2800rpm. You slowly go into 30% TPS and the rpm goes up and you see the commanded afr go to 11.8. Since it is commanding it and VE and maf tables look fine...you are under 4K rpm, so it's a mix of maf and VE and your maf and VE tables are higher than a stock SS, so there should be no problem there.

Your inj duty cycle goes up and your narrow band o2's go down. Again...fuel pressure? I'd check into fueling at this point.