MAF tune help - L83

[Cazbah362]

OK, need a little assistance. New Gen V 5.3, manual, LT5 cam, LT1 intake in a 240z - etc. I have turned off MAF and 02's to adjust the MAF. However when i fire up and check I get an average of ~ -20 (some higher / some lower) in the EQ err. When I change the MAF table, it looks like it stays the same (average about -20).

I have checked all my graphs, sensors etc, however I am in a spiral and not sure WTH I am doing incorrectly. If someone could take a second, look at my tune, and my logs - and point me in a direction. Any help would be appreciated

[CerealKiller19]

Are you trying to tune for speed density or tune the MAF? If you're trying to tune to MAF you need to leave the MAF enable.

Here's a good video to watch on MAF tuning. If you do it this way watch the videos after the MAF tuning to dial in your speed density table as well. You'll have to bounce back and forth between MAF tuning and Speed density tuning because as you change one the math gets changed for the other. It's kinda funky and time consuming.

https://www.youtube.com/watch?v=7IoWmLEmlvE

[Haans249]

1) Re-enable your MAF and your O2's and ensure your STFTs are enabled, but disable your LTFTs. Take your stock MAF Curve and add 10-15% on the whole thing. Write the tune to vehicle.

2) Ensure you have your wideband scanning correctly in HPTuners

3) Setup two MAF graphs; one using STFT's as the correction factor (this is for all part-throttle driving); and the other using the wideband (used for adjusting fueling while in Power Enrichment, say 5,000Hz and above).

4) Gather all of the PIDs, then log a short 5 min long drive keeping RPMs under 4,000. Check your MAF STFT Adjust graph that you made and make the adjustments to the MAF curve (just do a direct Multiply by %). Write the tune.

5) Take a longer cruise log (to fine tune the part throttle driving) and then start getting the RPMs up - watching your wideband to make sure you're not running too lean or too rich. Lambda should be around .87-.89. If they are close - make a full WOT run to see which way you need to go. Check the MAF graph that is using the wideband for the adjustments needed on 5,000 mhz and above (or where the STFT MAF graph starts to shows 0 adjustments in the higher mhz and above). Multiply by % from the MAF Wideband Adjust graph (on the higher Mhz only) on the first go, then write the tune.

6) Do this a couple of times and you'll have your MAF dialed in within an hour, barring no other issues arise.


Tip: For the MAF tuning, you don't need to worry about disabling DFCO - you should instead filter out any wideband readings above probably lambda 1.2 by inputting a filtering option such as: [50127.238]<1.20. Instead of disabling some of those features, you can just filter out a lot of the fueling transition from the wideband readings.

[davispaintandbody]

amazing explanation

[CerealKiller19]

Lambda should be around .87-.89.

If you have the stft enabled won't the ecm attempt to adjust the lambda to 1?

[Haans249]

If you have the stft enabled won't the ecm attempt to adjust the lambda to 1?

At normal part throttle driving yes, which is why you can use STFTs to adjust the MAF. But once you hit PE, typically 3,500 to 4,000 rpms and based on throttle position, lambda should be commanded to around .87ish, which is setup in the file. When in PE mode, trims are disabled and is the reason you can then use your wideband for the fueling adjustments to dial it in.

[CerealKiller19]

At normal part throttle driving yes, which is why you can use STFTs to adjust the MAF. But once you hit PE, typically 3,500 to 4,000 rpms and based on throttle position, lambda should be commanded to around .87ish, which is setup in the file. When in PE mode, trims are disabled and is the reason you can then use your wideband for the fueling adjustments to dial it in.

I misunderstood what you were saying in the previous post. I thought you were saying if the Lambda was .87-.89 before hitting PE then you should be good to start tuning PE.

[Haans249]

I misunderstood what you were saying in the previous post. I thought you were saying if the Lambda was .87-.89 before hitting PE then you should be good to start tuning PE.

No worries, I'm not great at explaining things. But, basically - you use STFTs to tune fueling adjustments pre-PE and then the wideband for PE adjustments.