Hey guys, as always I've been provided some great advice In here so I have a few questions regarding a buddys truck I'm trying to sort out. Ill try to keep is short and sweet since there's a but of questions I have. *Truck is more of a big show boat so max power over 5k hits will be few and far between bc its just massive.

Base: The truck is an 03 Silverado straight axled on 38'' tires. This truck is lifted idk how high but the rocker sill is at my chest and I'm 5'9''. Truck has a forged 370, 243s (11:8:1) BTR stage 3 truck camshaft with Longtubes and true dual exhaust. Motor has Delphi 50lb injectors and otherwise stock fuel system. 0411 ecu. 4l80 trans, stock convertor, stock rear 3.73 gear. Truck needs way more gear to get it up to speed, also being straight axled its all over the road driving but I'm told that's normal. Trying to get good data is pretty damn hard bc the truck just doesn't drive like a normal one.

Tune: So yesterday I did about 4 hours of tuning on it. Granted I'm still learning and new, it seems to be getting better. I did a few partial throttle VE table changes and some Maf table changes as well. I'm using an AEM Uego to monitor AFR but its lean as hell at idle and is 15.0 or so cruise. I'm using the cig lighter setup to power my Wideband so it may need an offset correction as well. Still learning, bear with me lol.

Issues/Pointers needed: Ive been reading a lot and see that between the Camshaft/ Longtubes tuning this thing in Blended (Ve/Maf) is gonna be/has been pretty tough. I disabled STFT during Open loop, but haven't Disabled LTFT totally. From reading I'm understanding that by disabling the LTFT thus will command OPEN LOOP all the time to prevent PE from messing with AFR therefore making the truck easier to tune?

Ive seen a lot of people tend to fail the maf to enable speed density but is it better to apply code modification to the pcm when deciding to do Speed Density? Whats preferred and why? This truck isn't a daily driver but my goal is to tune it as well as possible. Any tune advice/pointers/suggestions are greatly appreciated. Just looking to get this thing figured out!

attached tune/scan below.

 

here is the scan as well.

 

open loop doesnt disable power enrichment. PE is a fuel multiplier table that allows you to add fuel as a function of rpm/throttle angle. it's not exact, but we tidy it up by observing actual AFR and adjusting the VE table for any errors.

for me its much easier to tune the VE table with all the trims off. I disable all closed loop fueling and DFCO so the only thing adding or subtracting fuel on the VE is me.

unless it's boosted i'd leave the maf on it. turn it off to tune the VE, then turn the VE off and scale the maf. put the maf back on then work out the fuel trim parameters.


thats my method for mild cammed N/A motors. i'm currently applying the same stuff to tuning a mild cammed turbo motor but no maf. trying to make the closed loop idle fueling work properly is.....a learning experience.


also ls1tech's file hosting has been broken for a while so if you want anyone to see your tune you'll have upload it to google drive or some other cloud storage and add a public link here.

 

Thanks for the reply man. I'm gonna keep it blended VE/Maf but prob try to tune it in open loop perminantly. The closed loop idle has me chasing my tail right now. I'm also working off someone elses tune which almost has me to the point of starting completely from scratch as well. just so many variables here lol

thanks I didn't know that about the file hosting. Ill have to try the other options so ppl can view the scan/editor files.

 

It would be much easier to tune it if you could get your W/B to report correctly in HPT. If you search my name, you will see I went through a heck of a time trying to get my W/B paired correctly with HPT. BUT.... When I finally got HPT to display the same #'s as on my W/B display, tuning the VE table became infinitely easier.

With all of that said... You appear to be running lean. Your LTFT are all (+) numbers.. Meaning it wants/needs more fuel. Also, you should disable STFT, and LTFT, and fail the MAF, and set your EQ ratio to "1" in all cells 140 degree and above, disable DFCO as TRUCK DOUG states, and then before you start logging, go into the VCM scanner controls and clear LTFT history.. THEN, you can GRAPH AFR ERROR, and it will make getting the VE table set up quite easily. You can get it within 5% across the board within 3 tries with the W/B set up, and a safe space to "stretch the motor out a bit".

Go to your VE table, and do a split window and look at the 3D model of your table.. You see those spikes? Those need to go away. Your table when properly tuned will have no drastic spikes, or mountain tops, and no low (lean) spots. It is possible to use the vehicles NB O2's to tune. Just look up how to do a blended STFT+LTFT (maths) graph. It will get you closer than you are now, but the W/B will get the best results, and fastest! Vehicle needs to be DRIVEN while logging for best results. If it takes 1 person to drive, and you sitting in the passenger seat manning the computer and watching the scanner, then that's what you need to do. Long idle times heat up the IAT's and that will skew your #'s as well-another reason to drive it. Remove all BOGUS cell #'s from your graph before you copy and paste it over to your VE table. Also, after you copy and paste to your VE table, look again at the 3D graph and then smooth it visually, THEN burn the new tune, and start over.

 

Great info Kawabuggy Thank you. I will give what you said to do a shot and report back. I just looked at the VE table in 3d and holy **** lol. The biggest challenge I'm facing with this truck is that I'm working off of another idiots tune which I shouldn't even be doing but then again hes the local "LS Tuner" aka obviously sucks.

With the AFR error graph info where am I applying that to?

 

Way over thinking this. Get some clamps and run your wideband out the window and straight to the battery. Then, fail the MAF, and tune your VE table. Then fail the VE, and tune your MAF. When you're done, disable short term, enable long terms, done.

Use this site, their tuning guide walks you through tuning a 411 PCM step by step.

http://ls1tuningguide.com/tuninghelpfiles.php

 

01ssreda4: so by going directly to the battery this will eliminate any type of offset for a guaranteed number I can trust off of my wideband? I'm using the Tuning School course and its great but it doesn't tell you anything about disabling all the closed loop stuff to tune, so that's why I'm asking. ill def check out the ls1tuningguide as well, thanks for the info man!

 

Ive always run mine that way. Never had an issue.

 

I had mine run directly to the battery and STILL had to mess with the off set until I got the # reported in HPT to match what was showing on my W/B display. Your luck may differ.

 

I use a phone charger cig lighter plug to power the wb and I mounted the gauge in a small plastic box, added some harness type plugs to everything. Easy, safe, clean, cheap

 

I have mine setup the same way Cam. I think I'm going to try it straight to the battery as well just to see what it does. Always a pain in the *** trying to get all the small variables right just to get the tune right lol. but hey I guess we all have to deal with it

 

Apologies I see that listed in your first post now I skimmed through quick.

So the issue is your O2 gauge is showing different values than HPtuners scanner displays?

 

among other things yes. I have a variance between whats showing in HPT and what my wideband is reading BUT its so lean its hard to even see how off it really is. What I'm going to do is command Open Loop Fueling then see what the wideband is showing compared to my HPT reading. I think by doing that if I'm 100% commanding 14.7 at idle with STFTS off and my wideband is reading diff I know for sure its a voltage offset issue.

 

You tune ve/speed density in open loop. Your question confuses me. Reread my suggestion above. Literally one flash correction at idle should get you close to target if youre doing it right.

 

Ok, if i am misinterpreting just disregard, but....

Commanding 14.7 in open loop is not the same thing as actually getting 14.7 on the WB. If your airflows and VE table are perfect, then commanding 14.7 will actually get you 14.7. If your VE is 10% lean, commanding 14.7 will get you 16.0 on the wideband

 

Darth: correct. I'm going to load the Stock VE table and MAF. Turn off all closed loop options (open loop) then see what the wideband is telling me. at that point I will start tuning VE/MAF and see how it ends up. Also I found a spread sheet calculator for my wideband offset to figure out what I need to do to get my wideband to match what I'm commanding.

 

You need to sanity check your wideband...

enable trims and closed loop, watch PCM command stoich, observe what wideband reports.

 

With wideband connected to your logger, use DMM to measure voltage across logger's inputs... compare this to logger's reported voltage...

 

joe sorry but what is DMM stand for?