I'm unexperienced with tuning so I'm looking for some starting out pointers. From what I've read it seems like the very first thing to do is calibrate the MAF and then your WOT A/F ratios.
So I went out and logged several slow acceleration runs in 2nd gear up to red line. What I recorded was LTFTs, Mass Airflow, Mass Airflow Voltage, and Knock Retard just to make sure I'm not getting any.
I can pretty clearly see the different fuel trims and what percentage of fuel they are adding (about 4% between 2.0v and 2.3v and then 3.2% from >2.3v to when I hit redline ~3.3v)
From what I've read, the goal is to adjust your fuel trims to zero out what the ECU is adding. (its seems people general consider the acceptable range to be +-1.6%)
So that's all pretty clear but then from within Versatuner what should I be adjusting? I was expecting it to be the MAF calibration tables but that doesn't seem right when I am looking at them.
If anyone has pointers hook me up!
MAF calibration?
MAF calibration?
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Steve @ VersaTune
- Lead tuner
- Posts: 1157
- Joined: March 29th, 2010, 12:58 pm
Re: MAF calibration?
In order to calibrate the MAF, you need to record fuel trims during steady state operation, not acceleration. The MAF volt log you use to calibrate your maf should look like a stair step. Cruise, accelerate slightly, cruise, accel, cruise, repeat through the MAF range till you hit open loop.
Add or subtract g/s from your MAF table where you see the sum of the long term and short fuel trims are far off. Just make sure you are not looking at your trims during acceleration. There is acceleration enrichment involved there. Look at the trims when the throttle has been steady for a second or two.
Take a few logs and look for consistent data. Don't make changes based on a one time spike in stft.
It's also important to do a basic health check before you start. Make sure that there aren't any vacuum/boost leaks that you are masking with a MAF calibration.
Add or subtract g/s from your MAF table where you see the sum of the long term and short fuel trims are far off. Just make sure you are not looking at your trims during acceleration. There is acceleration enrichment involved there. Look at the trims when the throttle has been steady for a second or two.
Take a few logs and look for consistent data. Don't make changes based on a one time spike in stft.
It's also important to do a basic health check before you start. Make sure that there aren't any vacuum/boost leaks that you are masking with a MAF calibration.