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LS7 Trying to Use LTFT Tuning Until...
Newbie here trying to finalize removal of A&A V-3 Supercharger from 07 Z06. Engine was dyno tuned by installation shop (S/C & AHP 116 cam, no headers) in Delaware in 2015. After I did s/c removal, engine actually runs good but I knew calibration couldn't be optimum. I know a wideband will ultimately be needed but as yet am concerned about where to place sensor since I don't have header bungs:
1. So my 1st question is how much of a compromise would using a post-cat 02 sensor bung be? They are tuned out.
2. My LTFTs are dancing -3s to -5s, so trying to figure best way to improve, wondering about condition of 02 sensors, thinking about swapping side to side.
3. I followed a couple tutorials on setting up histograms for LTFT logging & could not get the MAF version to populate. Is that function not available for Gen4?
Attached tune & log hoping someone might take a look & advise.
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Fuel Trims swing from rich to lean
Newbie is Lost Big Time. Initially I was at -3s to -5s LTFTs. After playing around with the MAF & VVE fuel trim tuning my log showed lean fuel trims instead of rich. Thinking that I did something wrong, I put the original tune back in & the result is still lean STFT & LTFTs. Fuel pressure seems consistent. Do I have some mechanical issues, 02s, injectors, etc.? What am I missing here? I'm attaching the log & tune I previously sent (Baseline with 08Timing,Forum.hpl&.hpt) and the latest log of the same tune (verification#3.hpl). Thanks!
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Thankfully Some Progress, Still Need Lots of Help
1. Researched for 'rich after flash' & found Injector Control Offset 'Offset vs Inj Temp' which I think is whats being talked about, & Yes mine is zeroed. Problem is I can find instructions on setting it up.
2. Made sure engine was cold before flashing attached tune (FlashExp1withVEHisto) using graph from previous Log (Experiment1verification)--Logging resulted in continued Lean fuel trims (Log1withVEHisto).
3. Copied graph from (Log1withVEHisto) & pasted into tune (FlashExp2withVEHisto) VVE table. (Log2withVEHisto) showed fuel trims swinging back rich, so am somewhat relieved that my process is at least working/changing things.
Note: When doing these tunes I have been following instructions from online videos having me 'disabling' SD by minimizing Dynamic Airflow 'High RPM Disable' & 'High RPM Re-enable'. Addionally I am maxing out 'Deceleration Fuel Cutoff Enable & Disable ECT', maxing 'Cluch Fuel Cutoff Enable VSS' and lastly 'Disabling Catalyst Protection COT'. Please Advise if I'm on the right track here.
4. Hoping to do the MAF calibration with Fuel Trims tomorrow.
So when I paste the graph (histogram?) info into the VVE table, My next attempt is pasted into the VVE that I modified the last time, & so-on & so-on correct?
5. I see where I'm getting some knock, is this something that needs fixing soon & if so how? Sorry but the more I read the more I realize how little know. I am serious so I got to get my wideband approach method resolved. By the way, which wideband?
You Folks have been Great, Thanks!!
Been Barking Up the Wrong Tree??
Quote:
Originally Posted by
LS ROB
Hey Les, you can flash a tune in while the engine is warm/hot; it doesn't have to be cold/cool but you do want to drive around for about 15 min. before starting to log any data. As for MAF & VVE, you will want to do each separately. Copy from the MAF graph in the scanner & paste % half into the MAF table in the tune. Same goes for VVE. Just remember, when doing these separately, you need to disable the other. Tuning MAF=disable VVE and make changes to the MAF table. Tuning VVE=disable MAF and make changes to VVE table. These guys on here can tune both of those tables at the same time but as a novice, ive found it easier to start with the basics. And yes, you are on the right track with disabling half the tune before logging lol
if you would like, you can flash this to see if it helped. I tweaked the MAF based on your log "Log2withvehisto." If you flash this, then do a log, you should be able to see a pretty good difference with the next revision. This one i just copied your data from the MAF graph, pasted % half then smoothed to get it heading in the right direction.
Attachment 132239
Rob I appreciate your time & your help. I did another post a little earlier out of desperation on the very BASICS of the whole tuning deal, I feel so dumb. The more I read I'm now thinking that the disabling of VVE to tune MAF & disabling of MAF to tune VVE is in preparation of doing the data-logging to gather data for updating the tune in editor. I have been attempting to disable SD to tune for VVE which I'm now thinking voids everything I have done so far. I didn't realize that SD & VVE were same and/or they worked in closed loop. After you make changes to your tables in your tune how do you set the things you changed for disabling?
You mention the disabling of VVE & MAF for the respective tuning, can you explain the proper way to do each? Thanks!