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Thread: 80lb Injector LSJ question

  1. #1
    Tuner in Training antonio321's Avatar
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    80lb Injector LSJ question

    So i just installed mototron 80 lb injectors (SEM-110324-4) I used omegas spreed sheet and it the car ran fine but was rather rich. I adjusted the maf , but feel as if this wasn't the best way to go because some of the afr error values were as big as -20. this large of a maf adjustment shifted the cylinder air mass calculation in the upper RPM range at wot from .96-1.00 to .88-.96 which intern made the car command some rather aggressive timing which resulted in some knock. I adjusted the spark table (less advanced in areas of concern) but i was just wondering if anyone else experienced this while swapping in 80lb injectors.Would logging AFR errors against vacuum and adjusting the injector flow be better than skewing the maf?
    The car currently runs great aside from some minor hunting when coming of throttle going to idle. Iv included the tune used for calibration, the tune the car is currently running , and the last log before the timing was pulled.
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    Tuner in Training antonio321's Avatar
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    Also.. the Flow rate vs battery voltage modifier... i played with it ...and it seems like it really doesn't much if anything at all. kinda makes me wonder if it could be because the table stops at 13v and the car runs around 13.6 to 14.5 volts when running... i also played with the pws again , and while i got results i wasn't happy with them (hunting and bucking on desecration...so on ) really starting to look like resealing the maf and readjusting everything that has to do with airmass ...

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    Advanced Tuner omega_5's Avatar
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    Some of the extra documentation on 80's seems to have gotten lost in the old threads.
    Try dividing the Short Pulse Adder table in half, then tuning via fuel trims at low RPMs. If it's still hunting and running rich; zero the Short Pulse Adder table and repeat the tuning by trims.

    Tuning with the wideband is fine for power enrichment, but ultimately you're trying to satisfy the stoich during closed loop. It's good practice to utilize the factory O2 sensors, as opposed to fighting them.
    As well, despite the common recommendation to abandon the VE table, I'd suggest using it at least until 1800rpm. It will aid in evening out the idle.


    Edit:
    Ignore the part about zero-ing the table. I see you've already done that.
    Last edited by omega_5; 09-25-2013 at 12:18 PM.
    Tyler

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    Tuner in Training antonio321's Avatar
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    Yeah i've been meaning to get to ve side , but i may wait till i can afford some time on the dyno, its pretty hard to get enough hits in all the cells needed.
    I'll go back and try returning using the trims.
    Its running great now, fuel trim is low , and such its just the whole air mass thing. in your experience how far off are the trims/afr before readjusting things.

  5. #5
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    try halfing the offset tables. I found this exact same problem when I tried the same injectors in my car. You should never have to remove 20% of fuel with just an injector change. In a perfect world, your trims should stay exactly the same as they were before. But in the real world no more than 3-5% adjustment should be needed, and this is mainly because of tables we do not have access to.


    Here is some values for you to try. Download it or it will not display correctly. Under the Siemens 80's tab. I have verified these numbers in 2 LSJ cars.

    https://docs.google.com/file/d/0B4qs...it?usp=sharing
    Last edited by lwrs10; 09-28-2013 at 11:27 AM.

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    Tuner in Training antonio321's Avatar
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    cool beans i'll give it a shot tomorrow.

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    Tuner in Training antonio321's Avatar
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    Tried the half values , while it made the afr in the low to mid range closer ,the top end still took a lot of maf adjustment to bring the afr error close to 0...so much so that it was actually worse then before. it also introduced really bad hunting at idle regardless of the short pulse adder table, and it introduced some gnarly bucking when relaxing the throttle when cursing, and anytime you took the foot off the gas it went lean even with dfco disabled.

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    Quote Originally Posted by antonio321 View Post
    Tried the half values , while it made the afr in the low to mid range closer ,the top end still took a lot of maf adjustment to bring the afr error close to 0...so much so that it was actually worse then before. it also introduced really bad hunting at idle regardless of the short pulse adder table, and it introduced some gnarly bucking when relaxing the throttle when cursing, and anytime you took the foot off the gas it went lean even with dfco disabled.

    Those offset values do not even affect the higher part of the VE and MAF tables BTW. It affects idle and deaccel the most, where you have the shortest pulsewidth. The bad hunt at idle is very easy to fix. If you dont mind, email me your tune to [email protected], and I will see if I can help.

  9. #9
    Tuner in Training antonio321's Avatar
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    I guess i have more research to do, i was assuming since Manifold vacuum is( baro - map) that the 80kpa of vacuum was the same as 180kpa MAP, and that the ecm just flat lined the values or interpolated beyond that. The Flow rate table is also referenced to manifold vacuum and ends at 80kpa how dose the ecm calculate fueling beyond that?, i mean its pure speculation on my part,but i would think that the ECM would have to calculate Vacuum from BARO-MAP and carry the last known value out to infinity because i cant imagine there just simply aren't any calculations being done beyond where the Flow rate and Offset tables cap. When you consider the car from the factory was never meant to see over 10-12psi of boost which would equal roughly 180 kpa MAP ... it would kinda make since that that's where the flow rate and offset tables would stop...but once again all just pure speculation... Now that i say it out loud this would also explain why the afr is somewhat unstable near the top of the each gear ...pegging the tables ? Maybe try switching from Vac to Map in the offset tables ?

    Anyway...i stuck with the Omega_5/04 redline tables, tuned the maf then re-scaled my timing tables due to the cly airmass shift. And turned the Maf again using the fuel trims , then did some hand smoothing.

    the files below are where I'm at now. The Histograms are somewhat misleading since all the adder tables,fuel trims and DFCO are enabled

    3.cfg80lb_tuned_maf1-1 hand smooth.hptdrive to work 9-27-13.hpl
    Last edited by antonio321; 09-27-2013 at 12:54 PM.

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    Tuner in Training antonio321's Avatar
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    Spent some time looking at the logs. Vac is indeed the delta of ambient Barometric presser and manifold absolute Pressure. So 80 kpa of Vac is indeed roughly 180 kpa MAP. with that said the the Offsets are used during higher parts of the ve and maf ends (the last row anyway).

  11. #11
    Senior Tuner cobaltssoverbooster's Avatar
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    -120 kpa vacuum is roughly 17.4 psi boost

    80 kpa is roughly 23.6" of vacuum hg or -11.6 psi

    if it was kpa boost you would be correct the cap stops short. the numbers are lower at -120 kpa vacuum because the intake manifold is in boost therefore the pressure pushes back on the fuel coming out of the rail resulting in less flow. basics of fluid flow under pressure: flow moves towards the lower pressure side, and if pressure was exactly the same one either side you are essentially stopping flow. with that information you can see why boost at -120kpaVac(17.4psi) has lower flow multipliers than at 80kpaVac(-11.6psi). higher manifold pressure with a static fuel rail pressure means less flow more injector on-time. now when people run a rising fuel pressure regulator controlled by an engine manifold source the data stays the same. why, because the fuel pressure regulator controls the pressure differential ratio between the manifold and the fuel rail. in this case the injector flow remains constant requiring the data to be the same flow across the board.

    did that shed light on anything?
    2000 Ford Mustang - Top Sportsman

  12. #12
    Tuner in Training antonio321's Avatar
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    Ok that makes more sense ,i had the beans above the frank, tables aren't pegged, but the offsets are used the entire time?(affect the upper part of the ve and maf tables)
    Last edited by antonio321; 09-27-2013 at 09:23 PM.

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    Quote Originally Posted by antonio321 View Post
    Ok that makes more sense ,i had the beans above the frank, tables aren't pegged, but the offsets are used the entire time?(affect the upper part of the ve and maf tables)
    the offsets are used at all times yes. But, they have alot more effect at idle and deaccel than cruising and WOT. Say your offset is .6-.8ish, and your idle pulsewidth is around 1.1-1.2ms. That offset is almost half of your pulsewidth! But WOT, your pulsewidth is 15-19ms....that .6-.8 offset is alot smaller percentage of your total effective pulsewidth there.

    Get what I am saying? When you said it went leaner on the higher side of the MAF table it made me scratch my head.....I can cut my offset tables in half and while idle would be lean as hell, WOT would not change at all. I would love to see the tune you made when that happened...

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    Tuner in Training antonio321's Avatar
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    I don't have the tune as it got overwritten, but it was the same as the first file i uploaded( 80lb_maf tune_omega numbers_7.hpt) but with stock maf values and the injector setting from your worksheet.
    Maybe there's a possibility that some ECMs behave differently than others.

  15. #15
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    Quote Originally Posted by antonio321 View Post
    I don't have the tune as it got overwritten, but it was the same as the first file i uploaded( 80lb_maf tune_omega numbers_7.hpt) but with stock maf values and the injector setting from your worksheet.
    Maybe there's a possibility that some ECMs behave differently than others.
    while that may be a possibility, I have not seen it yet. Let me put together a tune for you to try if you dont mind.

    *EDIT*

    Try this out. Make sure you get all the tables, including the spark stuff. I fixed a few other things too for you, like torque management stuff, spark, ve table, maf, etc.
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    Last edited by lwrs10; 09-28-2013 at 11:40 AM.

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    Tuner in Training antonio321's Avatar
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    i'll give it s shot for the sake of science

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    added it above

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    Tuner in Training antonio321's Avatar
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    Gave it a go, worked great in the mid range. Low end and idle super rich (min pulse set to 1.2 maybe? i know before i was seeing pw as low as .7 at idle)

    top seemed to be as rich as before ..maybe a tad less. looking at maf cal side by side your number did take a tad less adjustment to bring the numbers in.
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    Honestly, after trying to figure out your log config, which by the way is not set up right for tuning an LSJ, you are not that far off. I will attach a config for you that will give you what you need, minus the wideband. I am pretty sure your wideband is not set up correctly because your fuel trims are very different than your wideband readings.

    Also I am running 19 pounds of boost on that MAF curve, so I would expect it to be a bit rich on your setup.

    Load my config and get a good log, after setting up your wideband. That will make it alot easier to help you out.

    I also recommend turning off your long term fuel trims until you get it trimmed in, or tuning it by wideband only after you set it up right.
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    Last edited by lwrs10; 09-29-2013 at 12:13 AM.

  20. #20
    Tuner in Training antonio321's Avatar
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    I'm not sure what you mean by not set up right for a lSJ was i missing something ?(minus the injector histograms). The only thing i set up and were primarily using was the MAF vs AFR error%, the last two histos were experiments and not used for tuning. all the other histos were set up out of the box from HP i just changed the pids to the correct one for the car lol. And what i see on the wideband matched whats recorded in VCM. (give or take a few points)

    Here's a log from the other night on the tune i had been working on using the omega numbers . my trims while not perfect are fairly low. (dfco is on so the numbers are a little skewed)

    I appreciate the help,but i think i'm just gonna stick with what i have. My original questing was about the Cyl Airmass shift that happens when tuning the maf, iv been looking at other tunes and see that it is common, even with your numbers i had to re-cal the maf enough to cause a significant shift. (although the shift was slightly less is some areas )
    There should probably be a warning somewhere about it and how it can cause the ecm to command some pretty aggressive timing.

    I am however very interested in building a better data base for the community, when time allows(and its not so damn hot out in Florida) i would like to revisit this ,i certainly don't running some things threw my car for the sake up experimentation. Its just like i said before , i have a tune that works great my only concern was if the CylAir change was normal.
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