Fuel Upgrade & Street Tuning

I grew tired of inconsistent behavior and bad data constantly re-appearing in my tune, so I finally broke down and bought a flow tested set of injectors with known offset voltage data and completely re-tuned my Elantra from scratch. It's all in the video. Because many of you might have questions to explore more about the topics that I touch in this video, I put a small checklist together for anyone else going down this road. Of course I'm using ECMlink, so much of the data below is, too. The same principles and features apply to most other tuning platforms, but the terminology may change.

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Boost leak test your intake system!

Set/check your fuel pressure, throttle linkage, idle switch and set your ISC operation to 30% at warm idle with all electrical accessories off. I made videos for this. You can use TPSadjust to correct your TPS range with ECMlink, but I did it manually in these old videos.
   • Tuning 101 - tuning with the car off  
   • Tuning 102 - Idle Tuning  

So... If you're lazy, just set or calibrate your throttle position sensor with ECMlink
https://www.ecmtuning.com/wiki/dsmlin... ...it's still correct. OK to be lazy.

Set your deadtime voltage offset values.
If you don't know them (like I didn't), then...
https://www.dsmtuners.com/threads/inj...
or... pay someone to calibrate them and give you the settings
or... buy a set of injectors that come with them like I did.

Set your global fuel and deadtime values
https://www.ecmtuning.com/wiki/basein...

Use tuning methods appropriate for the type of air metering system your car has.
• I have Speed Desnity: https://www.ecmtuning.com/wiki/sdvead...
• I have a MAF sensor: http://www.ecmtuning.com/wiki/v3mafad...
• I have a MAF sensor as well as Speed Density: https://www.ecmtuning.com/wiki/sdvead...

Ensure your ECU enters closed loop operation mode. KNOW THIS INFO!
https://www.ecmtuning.com/wiki/fueltr...

Start tuning... (all of this is in this video)
• Adjust your airflow (VE cells/MAF compensation) and deadtime to get your STFT and LTFT Lo values cycling within 3-5% of Zero and AirflowPerRev at idle between .24-.28
• Note that changes to your idle airflow data (MAF or SD) may affect the operation and calibration of the ISC (at least it does for me...).

Now verify that your global fuel settings are providing the desired results.
• requires a means of monitoring knock
• requires a wideband oxygen sensor
• Requires wide open throttle :)
• Wideband AFR ratios should match targets (maxOctane table) when you're at 100% VE
• 100% VE should be achieved between 5,000 - 6,000 RPMs (4g63/4 specific)

Tune the default closed-loop functionality of your tune first.
• Set your boost pressure to stun. Turn it all the way down if you can.
• Stay out of the throttle at first. Wide Open Throttle is not closed loop.
• Doing the off-throttle and low-load cruise cells first will save a LOT of fuel.
• The vacuum portion of the VE table improves your car's general driveability the most.

Lock the ECU into closed loop mode and repeat your efforts.

Along the way as you tune other things, you should tweak the throttle tip-in scale to normalize events that occur on your wideband sensor immediately after the throttle plate is opened.
• This is the EFI equivalent of having secondaries on your carburetor.
• Correcting for the lean fuel mixture caused by the surge of air resulting from opening the trottle plate can help eliminate knock and the resulting loss of timing advance.

Turn the boost up and repeat...

Watch your injector duty cycle at WOT. Ideally it shouldn't be operating above 80%. If global is correct and it rises above 80, then just like me, you probably need new injectors (which is why I made this video for you).