LTFT and VE Tuning Problem

I am fairly new to Tuning GM trucks, and have only been using hpt since march. With that said i am trying tune a 2002 Chevy 2500 LQ4 6.0 4L80 2wd.
Mods to the Truck:

Trick Flow CNC 225 Heads
Brian Tooley Cam: LS1/2 Stage III Cam 231/242 .617"/.592" 112+2
Holley High Ram Intake and Fuel Rails.
Holley 105mm TB
Injector Dynamics ID850 injectors.
Return Style Fuel with Regulator.

Jakes Stage II 4l80E w/~32-3400 Stall

Built 14 bolt Rear with 4.56 Gears.

Truck was tuned by 2 other people prior to me and also prior to the intake and injector changes. I have adjusted all the Fuel injector changes, MAP sensor Changes and TB Changes. Truck Idles fine and Drives good just doesnt make the power it should and i am lost on how or where to go from here. I have gone thru the Tuning School Books on GM GenIII and GenIV. Problem i am having is i cannot get any fuel trims, LTFT or STFT, to give me any data other than 0.00

I have tried changing a few things and still get no differences. I also have gone and done the reset LTFT and still do not get any data.

Here is my latest tune and scan file from driving around trying to get lots of cell hits. I also logged AFR Commanded vs VE and Wideband vs VE. Wideband is installed into Bank 2 Sensor 1 Location, B2S1 O2 is unhooked (is this causing a problem?).

Any advice or help will be greatly appreciated.

You need to have both narrowband O2's installed in order get fuel trims, sounds like you've removed both from your post

Your bank 2 o2 sensor isn't working, that's one small problem. You need to run open loop if you are going to disconnect any o2 sensors.

Have you tried tuning the vehicle in speed density to fix your choppy VE table? Then done the same thing with your MAF curve? The motor would be far better off if you included the VE table in this tune instead of running MAF only and even in MAF only it does use the VE some.

You are losing power with that intake and throttle body if you aren't running boost. Those are way overkill for this setup.

Quote:

---

Originally Posted by 5FDP

Your bank 2 o2 sensor isn't working, that's one small problem. You need to run open loop if you are going to disconnect any o2 sensors.

Have you tried tuning the vehicle in speed density to fix your choppy VE table? Then done the same thing with your MAF curve? The motor would be far better off if you included the VE table in this tune instead of running MAF only and even in MAF only it does use the VE some.

You are losing power with that intake and throttle body if you aren't running boost. Those are way overkill for this setup.

---

I installed the wideband just to do a comparison and picked up an O2 bung today. (will install tomorrow). and reconnect the B2S1.

I understand we left some power on the table with that intake and TB, this winter the truck is getting the D1 procharger off of his 14 Corvette stingray (vette getting F1, Cam, Meth). this is also the reason for such a big injector.

I have only switched once into speed density mode and truck would not even idle. so i reloaded the previous tune and was looking to see what all was going on.

Once i reconnect the O2 and get another scan I'll repost the files. Although even with both narrowbands installed i still did not get any fuel trims to be anything other than 0.00.

I am not sure how i can tune in speed density without being able to see fuel trims. is there a way i can do this with the wideband?

Thanks again for all the Help.

Yes, if using AFR instead of lambda you create an AFR error and that's how you adjust the VE table.

This "how to" is a good way to understand it, some of the stuff is different because it was made with 2.24 but the basics still all apply.

http://michigansnowmobiler.com/hptun...ons%20rev2.pdf


When you do go with boost this winter you'll want/have to ditch the MAF anyway when you upgrade to a 2-3 BAR OS. You'll outflow the old style MAF sensor so fast that you won't even want it.

PM sent.

Silly question but worth asking.. Did you add LTFT and STFT in the Channels...?

Yes i did, and havent had a chance to get back to the truck just yet. hope i will be able to this evening.

thanks for all advice.