Results 1 to 6 of 6

Thread: adjusting fuel..

  1. #1
    Tuner
    Join Date
    Mar 2008
    Location
    NH
    Posts
    132

    adjusting fuel..

    Hey all, first of all I am kind of a newbie to HPtuners, joined awhile ago but finally bought my own.. I am a 25 yr dealer tech so I am familiar with the factory side of things.. Just playing around a little, not causing serious damage.. coupla questions if anyone has any time..

    My own personal Guinea pig is a 2013 Silverado 5.3L.. bone stock..

    Already turned off dod, seen too many high mileage dod motors with fouled out plugs on the dod holes and burning more oil than I would like to see.. Once I get better at this I may re-enable it with different settings..

    would like to...

    1) eventually work on increasing my mileage some.. I am not a leadfoot, I really have no use to try and boost horsepower, unless that means less gas pedal needed and that means more mpg.. 70% of my driving is 40-50 mph with turns and some hills.. Infrequent highway use but if I could get mpg up better there I could use the truck more on the highway instead of grabbing the car all the time and putting too many miles on that..

    2) I have noticed on my truck that bank 1 and bank 2 differ on long term trims as much as 6-7 at some points, done this since I bought it new.. I have now verified with logging that this is consistent throught rpm/airflow, in fact now that I am logging it is now starting to annoy me, lol.. I have already gone thru looking for intake leaks,etc.. Smoked the intake system, and I haven't found any reason for this.. This isn't cause for alarm, but I thought I could tune it to correct this.. I am however unable to really find a table to correct differences between left and right banks.. There are tables for b1 and b2 O2 sensor rich/lean switching which have varied numbers and even a cold table offset but the minimum and maximum seem to be set to 450 right below it.. Looks like the tables aren't even enabled by the way the min and max are set at 450mv.. Might be reading it wrong but the help files included with hptuner do not show these tables or settings, hence not much of an eplanation that I can decipher.. Wondering if anyone has been thru this before and knows what I am talking about.. I'm thinking of opening the min or max and then adjusting one table slightly to even out the trim levels..

    3) Also wondering if I could actually use the airflow mode and O2 rich/lean VS airflow tables and adjust it slightly leaner just during my 40-50mph cruising, sort of like a lean cruise..

    4)I have been doing some reading and research, even helping out a coworker with a tuner on an older truck, but the guides don't seem to fit my truck in that I do not have the same VE tables that are shown in the guides.. Say I do disable my maf and drive it and log it, where would I make corrections??

    5) increase my throttle response for those times that I need it.. I'm not talking tire spin, I'm talking about when I need to move this thing out of the way of some oncoming texter/makeup artist, you know the delay from when you hit the pedal to when it decides it might actually feed ya some power, that's what I would like to help if possible..


    6)I'm still running cats.. How worried do I have to be if I try and optimize my spark and/or adjust my fuel slightly?? I'm not really concerned but thought I would post this and see others opinions..



    Thanks for any tips, suggestions, or even more links for me to read/browse and take notes from, especially from anything this new as that is something I haven't had a whole lot of luck with.. Tom

    P.S. already added my stock tune to the repository, been there for a couple weeks but hasn't shown up yet.. If anyone needs a stock tune on something fairly new from Chevrolet, let me know and if I can find it on the lot, I can suck the tune out of it...
    Attached Files Attached Files

  2. #2
    Advanced Tuner
    Join Date
    Aug 2012
    Location
    SV, AZ
    Posts
    447
    1) It can be done. We have the technology.

    2)This is more indicative of an exhaust leak than an intake/vacuum leak. You are reading that section wrong, they do work.

    3) See answers 1 & 2.

    4)Read up on parametric/virtual VE.

    5) Custom tuning will fix that, especially touching on PE.

    6)Not at all.

  3. #3
    Tuning Addict 5FDP's Avatar
    Join Date
    May 2012
    Location
    Rogers, MN
    Posts
    13,533
    I'll chime in on the PE settings real quick, just some simple stuff here.

    First, make sure you are in advanced view to see everything.

    To enter PE, the computer needs to see basically like 3 things, throttle %, MAP KPA and rpm as the main things.

    So under fuel > power enrich, there are a few things you can change. Looks like you already set your throttle % to 75% compared to 90% stock.

    Thats just fine and I'd keep it there, no look below that and you'll see the ramp in rate and the RPM delay. I prefer to set the ramp in to 1.0, thats plenty fast enough for getting the fuel there on time and then lower the RPM delay to 2,000 instead of 5,000 rpm. That should wake it up some.

    Also, they do tend to run rich up top from the factory. Once you figure out the EQ ratio you will see, it's like high 10's to low 11's for AFR. You can always lean that out some to like 12.0 AFR and still be safe.


    And go to Airflow > electronic throttle > Area rate limits. Click on the opening rate and you'll see that for 1st gear it has a 1,4,8,100,100 for that, set it too 100 in those 3 cells. Now you will get the max allowed opening rate all the time, when it lets you.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  4. #4
    Tuner
    Join Date
    Mar 2014
    Location
    Australia
    Posts
    98
    Quote Originally Posted by tek1229 View Post
    2) I have noticed on my truck that bank 1 and bank 2 differ on long term trims as much as 6-7 at some points, done this since I bought it new..
    Injectors are not always created equal... they are manufactured to a 'tolerance', so some injectors will flow a bit more and some will flow a bit less. The tolerance depends on the manufacturer, but can be as much as 8%. That's why people, who are chasing the perfect tune, will spend up big on 'flow-matched' injectors.

  5. #5
    Tuner
    Join Date
    Mar 2008
    Location
    NH
    Posts
    132
    Ok, thanks for all the suggestions, I haven't been ignoring your responses, just doing more reading and research, please bear with me..

    I'll probably smoke the exhaust and check for a leak, I doubt I'll find one but it takes about 5 minutes to check, I can do that while the oil is draining on the next lof..

    I was wondering if I was reading that section incorrectly.
    O2 sensor rich/lean mix-O2 sensor rich/lean threshold minimum limit is 450
    O2 sensor rich/lean mix-O2 sensor rich/lean threshold maximum limit is 450

    I read those two and it makes me think that 450 is locked down as the switching voltage for rich/lean no matter what the tables above are saying.. If I wanted to attempt to lower some of the tables I would need to change the minimum to my lowest value in the tables above? no big deal, no wideband yet so the only way I could possibly check to see if it worked would be to log my data before and after, see if my LT dropped in the areas I'm aiming at, see if it thinks it's happy with less fuel? Just an idea, not sure how out there it is..

    I will work on some changes to the PE settings, I don't want to change them too much, quick response would be good, but I don't need to go full bore 10's to 11's until I'm really hammering it..



    I've been doing even more research, It seems that my pcm(E38) doesn't really have any sort of VE table for me to work with.. There are lots of tables, and even a crank VE(which is all 100's) but no real VE table.. This is where the BlueCat program seems to come into play.. I found that, copied all my tables and low and behold there is that VE table I have been doing so much reading about, lol.. Now I could turn off my maf, do some more logging and then I actually have a VE table I can work with..

    As far as bank 1 to bank 2 I am still unable to find out how to even them up? I know it's not required but I thought there would be an easy way to do it.. Maybe I could enable injector gain and adjust injectors in one bank to even them out? I did notice the warning about high rpm issues, I won't be going any higher than stock rpm on this ride..

    Thanks again for the feedback, I'm getting there slowly... Tom

  6. #6
    Senior Tuner
    Join Date
    Jun 2007
    Posts
    1,100
    Nope...you can't really turn off your maf and run right, plus bluecat program never gives accurate values (compare by inputting the same values it generates over and over...it will come out different every time.).

    BTW: changing the rich lean cycling voltage will have absolutely minimum effect, those things switch from high to low almost instantaneously. What will improve economy is more midrange timing in both high and low octane tables. I do mine by setting high values in both, reduce kr in cells in both tables and then reduce low table by another 4ยบ.