My wideband is reading around the 14.0:1 area during most of my WOT runs. I have already done my closed loop tuning. Stoich is set at 14.737 and in the PE table the multiplier value is set to 1.2403. I am using LS1 Edit as well. Correct me if im wrong, but my A/F commanded is 11.88:1 since 14.737/1.2403 = 11.88 ?? Am I doing this calculation right or what, or does the calculation work different in ls1 edit?? What is the best way to go about getting this AF ratio down to where i want it to be?

 

Have you watched fuel pressure?

 

I am assuming the pressure is there, I have a walbro in the tank. Also if I was losing PSI then I would think that when I use the N20 it would blow up. The lean issue i am having is when off the spray.

 

I've been out of the game for awhile and still trying to absorb all these new methods but let me tell you how I would go about this.

First verify that your ltfts are going to zero when hitting WOT/Cell 22. If they aren't, they were obviously a positive value when you entered PE mode.

Once you've verified that, I would simply start bumping up your multiplier until you get the results your looking for.

.02

..a more specific list of your mods would b helpful

FWIW, I also run a 1.24 multiplier @2400rpm and above

 

mods are just headers xpipe, lid, ported throttle body, and removed emissions.

 

Make sure your multiplier is in Eq ratio and not lambda if you're using +1.0 for a richer mixture. Lanbda mode would be 11.88/14.63 = 0.81

 

So how do i know which i am in?

 

It does sound a little fugged for your mods, so what are your LTFT's doing during cruise? I would double check for any leaks that might be a factor.

 

and make sure your wideband is reporting accurately

 

The calculation looks right. The first suspect in the lineup
would be the wideband, very easy to mismatch the scaling
in the unit or the scanner (if these are hooked up for WB
data capture). Verify by the average closed loop readings,
with enough smoothing (and functioning narrowband closed
loop) you should see the magic number.

For the commanded and actual to be that far out of bed,
you'd need some serious error somewhere in the system.
I wouldn't assume anything good, a fuel pressure gauge is
plenty cheap or can be borrowed, though reading it whilst
at WOT can be tricky; I bought a cheapo Actron one,
added a "T" fitting and hooked up an electric sender &
gauge with an extended harness and cig lighter plug so
it's a toolkit piece that can be read (or logged even, with
another two wires) with the hood closed.

Probably want to take stock of the mods, the MAF etc.
with an eye to which ones would cause an under-reporting
of airflow or a short fuel delivery (e.g. using an '01-'02 IFR
table with '00 injectors, too wimpy a wiring for the big pump,
etc.).

LTFT can only enrich WOT mixture, they will never modify
the delivered fuel in a lean direction. However the LTFT
is your mixture history and might have something to tell
in a more general sense.

 

Brad8266 states, "Also if I was losing PSI then I would think that when I use the N20 it would blow up."

I need to get a guage like that.

 

 

The wideband is brand new. I havent ever touched the IFR table so its still stock. My LTFT's are between -4 and -1. When I dynoed last year it was also lean then on their wideband. Think I need to do more VE or MAf tuning?? I will be sure to look for exhaust leaks although i have not been able to detect any by sound yet. Timing is also stock.

 

Ill also check around my nitrous nozzle for a leak in the bellow. And when I am in WOT is the fueling based more on MAF readings or the VE table?? I may need to tune the MAF in the higher frequencies again.

 

I only use calculations to give me a starting point. Once you take some actual readings, then you need to forget them & adjust accordingly. IMO you need to bump the VE table up. Spraying a lean motor is asking for trouble!!! And get a press gauge.

 

I just went over the graph that I logged and at 5700 RPM's it started to richen up slightly, so wouldnt this tell me fuel PSI is ok? I guess i will go make a few WOT runs in SD mode as well as with the MAF plugged in and see which one is really off, or both might be possibly.

 

First, I'd double and triple check the exhaust for leaks...especially near the wideband. Then, I'd recalibrate the wideband and check to see the voltage the wb is commanding (based on the AFR it's reading) is the voltage your scanner is reporting.

If all of those seem fine, I'd replace the stock MAF & VE tables and start over with the VE in open-loop SD mode.

Just to recap quickly how it's usually done....you disable the MAF, MAF MILS, DFCO, PE (set to 1.0EQ or 14.63AFR), closed-loop enable temps, LTFT's, change OLFA table to command 1.17EQ (12.5AFR), and copy the stock hi-octane spark table to the low-octane spark table. Within a couple hours of logging/reflashing, you should have the VE table close to where it needs to be assuming you can keep the IAT within a tight range of a couple degrees...just use your filters. On a side note, I like to be a little on the rich side when it comes to the VE. So, you could multiply the whole table by 1.005~1.01 (up .5~1%) when your done. When you go back to re-enable the MAF/MAF MILS (while keeping the car in open-loop), multiply the MAF table (which should have the stock numbers in it) by 1.05 (up 5%) from 1,500Hz to 3,875Hz and 1.10 (up 10%) from 4,000Hz to 12,000Hz. This should get you close enough to dial in the MAF using the wideband just as you did the VE (commanded 12.5AFR vs WB AFR). After that, just put the following tables back to stock: OLFA table, closed-loop temp enable table, DFCO, LTFTs, and low-octane spark. Then, the spark and PE tables can be set however you like. For the PE table, I prefer 12.2AFR at peak TQ blending to 12.8AFR at peak HP. Spark is it's own animal and I wouldn't suggest adding more than 2~2.5 degrees over stock (even if you get no knock).

Again, this is my brief opinion on how this is supposed to be done based on all I've read on this board. Some may do things a little different...but, this has worked for me.

 

I looked at a log and my fuel trims are at 0 while WOT, and inclosed loop they are slight negative. I dont think there are leaks near the wideband because while normal driving it reports 14.7 give or take a very little,which tells me that there is no air getting in there messing with it. If there was a leak it would be innacurate all through. I only get lean during WOT.

 

I think you may need a little more maf and ve tweaking is the shot wet or dry if dry maf could deffinatly be the culprit.

 

its wet, I am thinking that I just need to tune it more to get this right, I cant find any leaks on it and am almost certain my fuel system works properly.