horist

ideal values are such that you're not pulling or adding fuel while driving... the values in that table match exactly to the amount of useable air actually entering the cylinders

I've been dialing mine in for the past couple days... just using short term fuel trims and trying to get them all as close to 0 as possible (for the individual cells in the histogram)

2MuchRiceMakesMeSick

How do you lower your short/long term fuel trims. What is the difference?

HumpinSS

iTrader: (1)

My guess would be the ve table

horist

yup, VE table.

Basically heres how I'm going about it...

I'm logging lots of data hitting every cell I can hit , then I set the preferences for the histogram to show the average value...

If it's above 0 then you increase the VE value for that cell, if it's below 0 you decrease the value in that cell (in the VE table in the editor). start off trying to get everything inline +/- 10 variance, then fine tune to +/- 4 .. during this time you also want to modify the cells around the cell being modified for a blending affect

Be sure to reset long term fuel trims every time...

Short term update much quicker and are instantaneous... long term cells are an average of the short terms ... I have long term disabled in my PCM so I'm tuning the VE table off the short term trims only

Here's my latest histogram... still has some work to do (I have a new tune ready, but working from home I don't get to be able to log on my way to and from work so haven't driven the car in 2 days now)

foff667

iTrader: (2)

man that kicks me in the nuts lol aight one question to add to that then...ive already messed with scaling my ifrs...would i be better off in any way tuning via the VE table strait? Or can i keep my ifr table the way it is and fune the short terms using the VE now? And is it even worth it seeing as i dont have a WB hooked up yet?

Thanks
Bill

HumpinSS

iTrader: (1)

https://ls1tech.com/forums/pcm-diagnostics-tuning/205133-ifr-scaling-pe-vs-rpm-tables-too.html

horist

basically I scalled the IFR table just to get it to where it should be for the 42lb (@3 bar) injectors... then I fine tune w/my VE table (using narrowband... i'm doing part throttle tuning now... so PCM is trying to maintain 14.7:1 ... narrowband O2s are very accurate at this AFR, but they become much less accurate further away) and finally fine tune my PE table for WOT

Another_User

I have been making some observations...I need to read some LTFT and STFT log data and I will post about it later...

marc_w

I'm with you, Bill.

Horist - I'm going to attempt your method here. Is there any correlation between the STFT's (or LTFT's), and the amount your increase/reduce the VE table?

Also, how did you disable LTFT's - is it something that's doable with Edit or HPT?

marc_w

Okay, I did some playing around at idle.

I set IFR's to stock (higher) values. (Previously scaled them by .924.)

I took my VE table... I was running 70, 80, 90 % in the lower three columns. Replaced it with my bone-stock VE.

I started off running my stock VE table scaled down by .924 (I was thinking backwards on accident). Reset my FT's, and started the motor. My LTFT's ran in the +14's.

I reloaded the stock VE, and scaled it up 1.05. (reset FT's again). This time I'm in the 10-12's.

Would it be normal to see VE values in the 115+ (percent) range (estimated), to get my FT's down to 0?

...or should I keep my IFR's scaled down where I had them, and then work from there?

I'm pretty much going against the grain here, increasing my VE values (lower VE's!), with a cam.

marc_w

Also, these values I've got now,are nowhere near what I've calculated out using NoGo's formula. The formula values were MUCH lower.

I'm kind of freaked out!

HumpinSS

iTrader: (1)

Gameover said there can be +100 ve i think the ceiling is 130. Make sure you dont have any vacuum leaks. Tonight i found out i had major leaks and the reason my trims werent changing was because of the un metered air

Another_User

Where was the leak?

marc_w

Sounds good. I might go take a ride in a few minutes...

Where were your vacuum leaks? The only vac sources I messed with were the breathers in the valvecovers. THey're both on tight.

EDIT: Actually, after letting this sink in my thick head some more... I realize that Mike H. did scale his IFR (albeit for his larger injectors), but he also said he's fine tuning with the VE.

I'm more comfortable with this (as my old LTFT's were 0 at idle), so I'm going to go this route.

HumpinSS

iTrader: (1)

I did a PCV mod for oil control and the hoses and barbs got weak and was allowing unmetered air right behind the TB

Hoses lost tension from the heat and the plastic barb got brittle and cracked a little. That is why my trims never moved and no matter what i did could never get them in line


Will be fixed tomorrow. I found all of this because i am in the process of pulling my manifold

horist

[QUOTE=marc_w]I'm with you, Bill.

Horist - I'm going to attempt your method here. Is there any correlation between the STFT's (or LTFT's), and the amount your increase/reduce the VE table?

[QUOTE]


So far from what I've seen there isn't necessary a correlation between how much off and how much to raise the table... I was having some cells where they'd be 21/22 positive, so I'd bump my VE up 22 for them and it'd go way too negative then ... I'm just doing it in small steps... I applied another tune tonight and got alot more white and stuff tha twas way off earlier is much closer...

I think my car's a little more finicky due to the large cam (232/240 593/603 112) and the extra cubes ... Key is get lots of data and hit as many cells as possible (I've been driving in 3rd gear past few days, also driving in 2nd on some slower roads just to get higher RPMs so I hit those cells)

Another_User

I am really starting to get pissed at VE tuning. The only time I can get my fuel trims to budge is when I scale things negative with my IFR. The I can move some of the trims using the VE table, but I still end up with parts that refuse to go negative. WTF.

marc_w

You were resetting the fuel trims, right AU?

Another_User

Yep. I even watched them start rolling up from 0. At low RPM and high vacuum they always seem to settle around 10-12, unless I tune it out with the IFR. But if it were a vacuum leak, it would probably go to 25 wouldn't it?

horist

Drove the car a lil tonight w/the new tune... wasn't able to get any higher RPM cells , but she's looking better