Did I do calc.vet right?

[bubba68ss]

I FINALLY got my wideband installed in my '02 5.3 with 4l60e. The only mods I have are a cold air intake. It runs great but I'm just trying to teach myself basic tuning.

There was a spot under light throttle where I noticed my LTFT's were in the positive teens (17-18ish) but at idle they were great. So I figured I'd try to correct the VE table and MAF. (*I checked fuel pressure and other things first)

I got all the tables set up, maps, PID's etc. I also got my wideband serial connection to work (PID showing AFR like the gauge, LAMBDA and EQ also). I went for a nice long log and built a new VE table (copy paste with labels, right?) and the MAF (multiply?). Everything seemed like it all made sense because the maf range correction was about 12-13% off. The VE table was about 20-30% off in respective tables though...

Then I got to thinking did I set up everything right? Do I have to modify a file somewhere to specify my LC-2 WB? Is that calculation reading off something else like LTFTs or something and making a false correction because today i noticed my fuel trims were almost the opposite---negative. still good at idle (-4 to 0)

I did have to use Scan and Tune to program my V2 to get the WB to work... but that's the only place I specified what I had...

[bubba68ss]

only tune changes i made beforehand were to disable cat protection and set maf enable to 400rpm

[joecar]

Please post before and after tune files, and log file.

[bubba68ss]

Here they are. before, after and log 1 and log 2 (idle)



22527

22523

22524

22525

[statesman]

Where did you get your injector data?

[bubba68ss]

It is a stock 2002 5.3 with flex fuel injectors (33 lb). Just noticed I uploaded the wrong BEFORE file. I’ll fix that

[joecar]

ok.

Also post the stock file, please.

[bubba68ss]

I've uploaded the right before file.

I only have the stock file in .cal format (TC) which I modified to standalone operation in RT Tuner a year ago, flashed in my PCM, read with efilive ('before' file), flashed into my licensed pcm, and then modified from the calc.vet process ('after' file). I don't see a .ctz L59 file in the dropbox to upload for comparison but the only difference is vats off and emissions/code deletes

[statesman]

It runs great but I'm just trying to teach myself basic tuning.

After looking at your log... I'm guessing that you've never driven a well tuned LS1.


There was a spot under light throttle where I noticed my LTFT's were in the positive teens (17-18ish) but at idle they were great. So I figured I'd try to correct the VE table and MAF.

Yep, I noticed trims actually go to around +24 near the end of your log... it can't run great with trims like that, unless you've done a few hundred miles on the tune and the PCM has had time to 'bake in' those crazy trims.


It is a stock 2002 5.3 with flex fuel injectors (33 lb). Just noticed I uploaded the wrong BEFORE file. I’ll fix that

Your MAF airflow readings look too high for a 5.3 engine, which makes me think that your injector data is wrong. I very much doubt the injectors are flowing the 33lbs that you think they are.

[bubba68ss]

What’s the relation of injector flow rates to maf reading?

[statesman]

They move with each other.... reduce your injector flow rate in your tune and you'll have to reduce your MAF readings to get correct fueling. Some of the Gen4 PCMs have a hard coded limit of 63.5lbs for the injector flow rate table, so if you fit injectors larger then that in those vehicles, then you have to 'scale' the tune.... which is putting in a flow rate lower than the real flow rate and then adjusting the airflow tables to get correct fueling. You also have to adjust spark tables when you scale the tune, because the PCM is seeing a different cylinder airmass.

You can use any number for the injector flow rate and then tune the MAF and VE to that injector flow rate... it just becomes a 'scaled tune'. When the tune is scaled, it does create other problems with the PCMs internal calculations, mostly relating to torque calculations.... so it's always better to use the correct injector flow rate when possible.