2k1vert

I have just installed a set of LGM Long Tube headers, RT High-flow cats, GHL exhaust and a Blackwing cold induction system on an otherwise stock LS1 2001 C5 convertible. My Long Term Fuel Trims were running 0-7% prior to the install and I had very little KR. Now after the mods, I'm finding that my LTFT's are staying positive and usually not matched. I.e. Bank 1 is 11.7% and Bank 2 is 7.0%. They will actually go as high as 25% at times. My KR went as high as 4.7%, but I really did not hit it to hard with today's logging. Yesterday I redlined it several times and hit 131MPH and saw a KR of 9.9%, but found that my air bridge had slipped partly off.
I'm new to both EFI Live and LS1 Edit, but I really want to get these trims back in line. I would like your advice on what changes I should go after to get this corrected. I have over 4 hours of runtime to allow it to relearn.


You can download the EFI Live 6 log for review at http://home.nc.rr.com/exithere/2k1ve.../LTFT_lean.efi , but it requires EFILive to playback.


Thanks
2k1vert :cheers:

Godspeed

I would scale down the IFR table until the LTFT are back in line.

Bink

I can't see your file because I only have V5 on this computer.

From what you indicate you definitely need to adjust your LTFTs. Your probably too lean and that's causing the knock ( couls be false KR if your Headers are banging).

It's not uncommon for longtubes to cause unequal mV (%LTFTs) output due to placement of the O2s.

Make sure you have everything buttoned up - No unmetered air.Give the "learning" by the PCM a chance to settle down after the airbrige leak.

Do a 15- 20 minute run of relatively agressive driving . But try to stay out of WOT range as you won't need this data.
Average your LTFTs in cells 6-15 ( some say use only PE cells 3, 7, 11, 12, 13, 14, 15) and see how the look. If they come out to say ~+12% then in Edit go to-> Eng Cal-> Fuel Tab -> IFR Table. Multiply by the whole IFR table by 90%. This will tell the PCM that the injectors are smaller....and the PCM will then increase the Injector Pulsewidth to compensate . The result is more fuel and the LTFTs will come down about 10%.
Drive around for 20- 30 minutes and rescan to see where your averages are at. You want 0 -> -7% LTFTs. Hopefully, you'll no longer experience KR.

Hope this helps some. Good Luck.
joel


[Modified by binksZ06, 5:01 PM 12/31/2003]

2k1vert

Godspeed & BinksZ06
Many thanks for your suggestions. I edited the IFR to 95% of it's original values and went agressively driving for 45 minutes. This really seemed to have done the trick. I turned higher RPMS (6258) and everywhere in the middle. I experienced KR only once of 1.4%, which is a major improvement.

My LTFT's sit at 0% at idle and averaged 2.5% with a max of 8.6% It seems to be tuned as well or better than it was before adding the mods.

BinksZ06, I will review what you said and see if I can determine the averages while in those cell's.

Lou, I'm completely tickled with the LT Headers, RT cats and X-pipe. It really seems to have brought the car to life.

Happy New Years Eve!!!

2k1vert :party:

dpd

have you used edit yet to change any of your parameters yet? if you did change anything,if you put your original program back,does your problem go away?from your #'s that you posted,you are running lean.you also state that at times it goes to +25[maxed out].before i would go and change any parameters[you may end up just masking the problem].make sure you are not sucking in any unmetered air from anywhere.make sure the coolant temp sensor didn't take a shot during the install or the harness isn't up against the header.coolant temp influences injector duration[on/off time].a bum sensor input could just be telling the engine to run lean.a bad airflow meter could also make you run lean[it thinks it's seeing more air than it actually is].could it possibly be the blackwing?you didn't mention any fault codes or check engine light.did you have any faults?
with efilive i would look at coolant temp,airflow,manifold pressure,and intake temp as these all influence fuel and timing.a false signal from these alot of times don't trigger a fault,but will make the car run like hell.
i would look for the cause,if any,before i would start to change any pids.
i do remember reading about some cars being allergic to the blackwing,that it would really flip the car out[but i think it was a rolling/surging idle with screenless maf's],but just a thought.

2k1vert

Thanks again for the info. My ECT is reading what it normally reads and I'm 99% sure that I do not have any unmetered air entering any longer. I did let the PCM relearn for 1.5 hours after reconnecting the airbridge and then verified my LTFT's. From there I edited my PCM for the very first time and changed the IFR by 95% and all seems to be very well. I don't think anything is being masked.

regards
2k1vert :cheers:

Bink

As long as your LTFTs are positive the PCM will add same amount to WOT. Stock PE-AFR is rich at 4400 - 6800 ranging from 11.99 - 12.22, respectively. Best performance is around an AFR of 12.9 (on a Dyno). You don't want the stock PE-AFR richened by the positive fuel trims. Just my $.02.

2k1vert

Thanks BinksZ06.
I'm trying to understand what you are telling me. I thought that I had read somewhere that during WOT (Open Loop) that the Fuel trims were ignored altogether. If LTFT's values are applied at the time of WOT (OL), then I should be concerned. So what you are saying is that I need to get my LTFT's down to zero or negative? Do I need to do this across the board for all RPM's or control it within the RPM range you specified? Again I would use the IFR table to make the change?

:cheers:

Bink

You want zero to negative values in LTFT cells 5->15. Adjust the IFR until they are between zero and Negative seven. Scale the whole table, all kPAs, by a percent (95%?).

Wt99C5

This explanation is awesome. How, where can I learn more about each table in LS1Edit? Also how can data collection from EFILive be interpreted and then determine which table it Edit needs to be modified. Awesome thread. :cool:

2k1vert

I've been getting some conflicting infomation on how to adjust your LTFT's. There seems to be two approaches to accomplish the same task. 1st is to adjust the Injector Flow Rate table and the 2nd is to adjust the Mass Air Flow tabe.

Here is some decent reading: http://ls1edit.slowcar.net :cheers:

Wt99C5

Been there and many other sites, but I can't seem to make the connection between EFILive data and where and what to do in Edit. binksZ06's post tells you what your looking at, where to go in Edit and most importantly WHY. And yes conflicting information seems to be very common.

mfrnka

A few more for you...

http://www.ls1tuning.com/iboard/

http://www.ls1tech.com/forums/forumd...07cb0c4671&f=7




[Modified by mfrnka, 9:06 AM 1/1/2004]

Wt99C5

Hey Mike, yeah I've been snoop'in around on these sites to. Guess I need to keep working at it. PS. Really enjoyed meeting you and going for a ride a few weeks back.
When's our next lunch mod meeting ?
:party:

Bink

Tuning Education:

1.)Subscribe to the LS1Edit list
2.)Read Probst's book on Corvette Fuel injection
3.)Read the LS1Edit Archives - start at the beginning, it's time consuming but very useful. You'll be able to determine outdated, outmoded methods by reading the list.
4.)LS1Tech follow posts in the PCM section.
5.) Do a search on LS1Tech.com for all posts/ Threads by NoGo. NoGo provides accurate info and he's great at explaining tuning. NoGo is the MAN
6.)EFILive.com Tuning Forums - great for general use of Scanner.

I did alot of searching and reading. Asking questions. The above list provided the most "Bang for the Buck" i.e. most info with least amount of time invested.
Remember the internet is full of myth.....9 months ago most everyone stated, categorically, that the VE table (we see in Edit ) is Not used by the LS1/LS6. It is used...and there is proof on LS1Tech in the PCM section (see one of the "sticky" posts at the top of list). My point is follow the info put on the board by the Gurus (e.g NoGo, jfpilla, NEVRENUF, pKincy, ChrisB, Cal, EFILIVE and Topless Texan).
Hope this helps some.



Happy New Year!!!! 2004! :D


[Modified by binksZ06, 10:31 AM 1/1/2004]

2k1vert

Joel
Your insight on the best approach is much appreciated.

Thanks for taking the time to help the misguided and confused. :lol:

Wt99C5

I could not have said it better Thanks ! :cheers:

Bink

MAF vs IFR fuel trim adjustments - the consensus now seems to be to use the IFR table if your MAF is stock (i.e. you have not ported or previously rescaled it). The IFR table only effects fueling.
If your MAF is ported or nonstock then use your MAF table for LTFT fuel adjustments. The logic being if it's been modified(MAF) then the table has also been rescaled. Further changing/scaling is needed. The problem with rescaling the MAF table is that it has global use in the PCM. Many parameters/functions depend on it's input (g/sec or g/cyl). Changes in the MAF table have farther reaching effect (e.g.Timing Advance).

Seems that MAF tuning is a holdover from LT1 Tuning. That's a different duck. In fact, CAMAROHOLIC told me NOT to learn LT1 Tuning as it would be a waste of time...too little can be transferred to LS1. CAMAROHOLIC is an LT1/LS1 Guru on LS1Tech.com
In fact many have replaced their modified MAFs with stock MAFs for IFR adujsting of LTFTs. FWIW. :thumbs:

2k1vert

Just to funny, I basicly just finished reading the same info @ http://www.ls1tech.com/forums/showthread.php?t=111196

Sweet. I modified IFR yesterday by 95% with great success, I guess I should have went a bit further to get into the negative numbers. Too bad I don't have a Wide Band O2 sensor (yet).

Thanks again. :cheers:

Bink

I don't think anyone is misguided or confused. :lol: I'm still learning like everyone else. I have always been amazed at the kindness and thoughtfulness of guys when I ask questions. I'm just trying to give a little back. When you guys feel confident with this - then it's your turn to help carry the ball. :yesnod: Good Luck...Keep us posted on your efforts.
:flag
ps - I'm a two finger typer....you guys are way too fast for Me :lol: :lol:


[Modified by binksZ06, 11:00 AM 1/1/2004]


[Modified by binksZ06, 11:03 AM 1/1/2004]