MrVette90l98mt

Hey guys, I have an LS3 EROD create engine kit in my 1990 Vette ZF6 speed and I am in search of the stock OEM LS3 corvette MAF calibration table parameters.

The problem: Check engine light on with Bank 1&2 too lean LTFT is +20-25% fuel with Bank 1 & 2 too lean and O2 monitor will not run. I need this fixed for CA emissions. Car runs and drive fine all the way to redline.

I've done some quick research and understand the MAF calibration for LS3's vary with car / intake system and MAF location is important. EROD instructions say use a 4" ID pipe installed X,Y from TB and air filter. I am using the Stock OEM LS3 vette intake on my C4 assuming the MAF calibration was the same for all LS3's (space is tight and the C6 intake is a cleaner install). I also found some pin holes in the CAT down pipe assy and temporarily patched them with O2 safe sealant (the exhaust shop did a terrible job and I bought a TIG welder to fix / re do, still need to set it up) I figure flashing is quick and easy proof of concept rather than spend the time and money building an intake. I bought HPTuners to correct the speedo using the stock ZF6 VSS...the Pulse rate was far too slow for the LS3 ECM to understand so I installed a T56 sensor and made a custom 17T reluctor wheel and calibrated for my wheel size so VSS has no influence for the LTFT issue.

Current LS3 EROD MAF calibration table LB/H vs Hz:





Thanks in advance!

Build thread:
https://www.corvetteforum.com/forums...pe-clutch.html

Corvalex

Here is a complete stock tune.

Unreal

That being said, it shouldn't take more than 20 minutes and a few revisions to dial in the MAF on that car. Start by knocking 15% off the maf if all your fuel trims are +20 and go from there.

schpenxel

Indeed.. if the goal is to just get through emissions then just change the whole table by 20% or whatever and go for it

MrVette90l98mt

Thank you Sir!

I was surprised to see the MAF calibration differ by so much. Does this make sense why I am seeing my LTFT at ~+25% with the current MAF cal differences? I'm no expert in tuning but I do have an A.S. degree in automotive systems but tuning was never covered. I also changed career paths. Today I got a base line log file and plan to flash with the new MAF cal and data log new tune tomorrow. Hopefully all goes well.

Difference was calculated (EROD - OEM '12 Vette) / OEM '12 Vette

Stock EROD (MT) OEM '12 LS3 Vette (MT) Difference
0.708 3.093 -77.12%
0.708 3.093 -77.12%
0.708 3.093 -77.12%
0.708 3.093 -77.12%
0.708 3.093 -77.12%
0.708 3.093 -77.12%
5.032 8.143 -38.20%
12.694 13.496 -5.94%
19.060 27.738 -31.28%
24.589 30.880 -20.37%
29.737 35.225 -15.58%
34.962 40.770 -14.25%
40.721 47.517 -14.30%
47.393 55.465 -14.55%
55.016 64.615 -14.86%
63.545 74.966 -15.23%
73.071 86.672 -15.69%
83.993 99.839 -15.87%
98.541 114.406 -13.87%
113.012 130.715 -13.54%
122.331 148.800 -17.79%
137.225 168.619 -18.62%
153.200 190.244 -19.47%
170.240 213.636 -20.31%
188.408 238.793 -21.10%
233.181 265.736 -12.25%
256.307 294.454 -12.96%
280.874 325.075 -13.60%
306.978 358.101 -14.28%
334.760 393.259 -14.88%
364.516 430.547 -15.34%
396.631 469.966 -15.60%
431.464 513.029 -15.90%
469.309 559.128 -16.06%
510.068 608.040 -16.11%
553.423 659.877 -16.13%
599.050 714.740 -16.19%
646.759 772.540 -16.28%
696.673 833.224 -16.39%
749.014 896.778 -16.48%
804.003 963.485 -16.55%
861.813 1035.176 -16.75%
922.572 1110.997 -16.96%
986.422 1190.946 -17.17%
1053.505 1274.988 -17.37%
1123.966 1362.439 -17.50%
1197.943 1453.729 -17.60%
1275.552 1548.859 -17.65%
1356.765 1647.568 -17.65%
1441.475 1749.779 -17.62%
1529.567 1855.618 -17.57%
1620.961 1966.562 -17.57%
1715.819 2083.516 -17.65%
1814.510 2205.595 -17.73%
1917.439 2332.141 -17.78%
2024.961 2463.311 -17.80%
2137.130 2598.353 -17.75%
2253.771 2736.064 -17.63%
2374.753 2877.820 -17.48%
2499.927 3029.268 -17.47%
2629.322 3186.448 -17.48%
2762.910 3351.342 -17.56%
2900.985 3538.680 -18.02%
3043.914 3711.736 -17.99%
3192.064 3890.477 -17.95%
3345.331 4074.997 -17.91%
3503.409 4265.392 -17.86%
3665.423 4461.755 -17.85%
3829.995 4664.180 -17.88%
3995.429 4872.763 -18.00%
4160.206 5087.597 -18.23%
4322.859 5308.777 -18.57%
4481.922 5536.397 -19.05%
4635.928 5770.552 -19.66%
4783.408 6011.336 -20.43%
4922.896 6258.843 -21.34%
5066.147 6513.169 -22.22%
5209.398 6774.406 -23.10%
5368.083 7042.651 -23.78%
5479.353 7317.996 -25.12%
5683.306 7600.537 -25.22%
5892.280 7890.368 -25.32%
6106.335 8187.583 -25.42%
6325.532 8492.277 -25.51%
6549.932 8804.544 -25.61%
6779.595 9124.479 -25.70%
7014.585 9452.176 -25.79%
7254.961 9787.728 -25.88%
7500.784 10131.231 -25.96%
7752.116 10482.780 -26.05%
8009.017 10842.468 -26.13%
8271.548 11210.390 -26.22%
8539.772 11586.640 -26.30%
8813.750 11971.313 -26.38%
9093.537 12364.503 -26.45%
9379.202 12766.305 -26.53%
9670.801 13176.812 -26.61%
9968.397 13596.120 -26.68%
10272.053 14024.323 -26.76%
10581.829 14461.514 -26.83%
10897.783 14907.788 -26.90%

I guess there is a huge flow characteristics difference between a 4" pipe and the LS3 Vette velocity stack style intake.

Any thoughts on how much a 6 in long 4" diameter extension tube will have on MAF calibration?

Intake pic:

schpenxel

It doesn't matter what the stock values are.

Post a log, post the current tune and I'll show you how to get it close enough.

MrVette90l98mt

I think i'm close enough! most of the time the LTFT are +7-12% and only go higher when lifting or coming to a stop.

I will have to update the logs later they are too large of a file size to post (45min long) i will get a screen grab and post a video in low resolution keep it under the 5MB limit.

EROD base log:


idle and rev after MAF re-calibration stock LS3 MAF CAL:
maf recal start and idle.hpl

After calibration drive:

My stock EROD tune with speedo recal:
read before MAF re cal 6 25 17.hpt

Current tune with OEM LS3 Vette MAF re-cal
LS3 oem Vette MAF recal with speedo 3.33 recal.hpt

schpenxel

Sounds close enough to me, originally it sounded like you were just plugging in different stock values and hoping one of them worked