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Thread: I need help learning to tune

  1. #1
    Electronic Ignition!
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    Question I need help learning to tune

    I have been trying to read anything I can find on tunerpro and do this on my own but I cant my brain is hurting...

    My car is 1994 Camaro z28 automatic trans, I put flattop Hyperutectic pistons .030 over in, The cam is a bullet 288/196-10HR 236 intake @.555, 244 exh. @.555 , LT4 springs, chromoly pushrods, some adjustable guide plates, and injectors, and LT headers, light port match on the intake side, used roller rockers that might be 1.6 RRs. So it doesn’t idle anymore unless i give it a little gas. It does start and run tho. I did manage to download the bin and start working on it. For the easy stuff like AC delete, air injection delete, 3row radiator. It has a CAI, Ill have to make a separation piece for so it is really cold air. I have a 52 mm BBK I haven’t put on yet because I’ve been afraid that would stop it from running then I wouldn’t be able to get a comparison Data log. I’m new to tuning so I could be wrong there. If there’s something else you need to know about the car/build, that’s all I can think of for now. I haven’t pulled my computer to check the computer number yet. I just need to know how to tune this thing now. Any help or guidance and or direction would be greatly appreciated.

    I have read this

    http://www.gearhead-efi.com/Fuel-Inj...amaro+auto+adx

    I have been googling and reading quite a few related articles. But I like a plan of attack, like (I’m speculating here)
    first - fuel tables
    Next - spark tables

    What I should change and the order I should do it in?

    Found this read it too.
    http://www.gearhead-efi.com/Fuel-Inj...mpala-Caprice&
    Tried this out of there

    "Idle speed based timing corrections

    EE has a mechanism that makes fine timing adjustments in an attempt to stabilize idle rm errors, due to the fact that timing can make minor engine speed adjustments more quickly than the idle control valve.

    On a car with a lighter rotating mass (such as an aluminum flywheel), or with quite a bit of natural idle surge from a cam, the stock corrections may be too extreme.

    Typically anywhere from 50-150RPM of surge is normal for a larger cam or a light rotating mass, and trying to fight it can end up causing larger speed fluctuations and instability.

    Try lowering them substantially to try to let the car idle more naturally. This is also recommended if the base timing (above) was increased dramatically, as the stock settings may enter dangerous timing territory during a large RPM error.

    For example, if a tune at 32 degrees @ 700 RPM idle drops to 500rpm, with the stock settings it would have 37 degrees of final timing, possibly with even more from the coolant temp adder table!

    The following settings work well with an aluminum flywheel and a mild cam."

    It still didn't Idle.
    I tried a tune off the F-body site linked there. I think if I could have checked the lt4 medium cam box and medium cam improved Idle it would have been a good starting point, but they are greyed out. Anyway If any one is willing to explain to me in simple terms or send me a similar bin where I can compare the two and figure it out on my own that would be great.

    I have already flashed the bin on the car with the idle timing changes, If I can't get open loop idle to work, after I figure out how. I'll enlarge the Idle passage, but I want to exhaust bin changes first. This is what i'd like to do out of that article.

    "Idle BLM splits, and the idle passages

    If you have tried all of the tricks in the headers and cam sections, as well as the individual fuel trims mentioned earlier in this section, and you find your BLMs are still split, you might have to give up and run open loop idle.

    But first, one major cause of BLM splits at low RPM is insufficent feed through the idle ports in the intake manifold. Due to the length of the plenum, idle air is supposed to be drawn through a series of ports on the bottom of the manifold instead of through the plates to ensure even low RPM feed.

    Ensure your IAC counts are fairly high (35+), by closing the throttle plates. If further adjustment isn't possible, enlarging the bypass hole in the throttle body may be necessary. Some aftermarket throttle bodies don't even have an idle hole, contributing to the problem.

    Open Loop Idle

    For substantially larger cams, dealing with corrupt o2 readings which tend to force a very lean idle may be impossible or undesireable. Not to mention, big cams really like to idle rich, and closed loop simply will not do it.

    The LT1 doesn't have open loop idle settings, however you can cheat using the PE tables.

    Ensure PE activation around your idle speed happens at 0% TPS, and then use your low RPM PE table to affect idle fuel mixture. Remember there are two PE tables, rpm and temperature, make sure they both correspond to your desired settings.

    idling in pe mode

    Somewhere between 8-10% added fuel seems to be an appropriate starting point for most cams, but that depends how accurate your VE or MAF table is in the first place.

    Tuning for Headers

    Reference Voltage

    When installing headers on an LT1, due to increased distance of the o2 sensor a change in exhaust pressure near the o2 sensor, as well as a slight increase in resistance due to o2 extensions, and an operating temperature difference, increasing the o2 swing voltage about 50-75mv is reccommended as partial compensation for what usually becomes a slight lean condition.

    Experimentation and reading spark plugs may also assist in getting a true 14.7:1 AFR once longtube headers are installed.

    o2 swing altered for headers

    Integrator Delay

    Changing the distance of the oxygen sensor in relation to the exhaust valve will change the time that exhaust gasses (and obviously the fuel corrections being measured by the oxygen sensor) will take to become measurable.

    As the stock calibration expects the change to be measurable fairly quickly, the integrator becomes particularly unstable and innacurate if the delay is not increased. The effect is more dramatic at lower airflows.

    Making the integrator delay too large may result in a delay in fuel corrections, but increases stability dramatically. For longtube headers, doubling or even tripling the integrator delay is reccommended.

    int delay altered for longtubes

    Tuning for Cam Swaps

    Also see "Stabilizing Idle"

    Pulling Timing

    The stock timing table has a substantial amount of low rpm timing in driving range. Cams which are less efficient in this range require a substantial reduction in timing to avoid cam surge.

    It is reccommended that timing be completely reconstructed so it increases gradually to the new torque peak of the cam. This is one situation where just increasing timing until you encounter knock would be a BAD idea.

    This should be done at least to a certain extent before any other tuning is attempted, as cam surge can cause map fluctuations, affecting fueling, and also cause MAF inaccuracies.

    The map below was necessary to eliminate cam surge in a fairly small cam, larger cams may require more dramatic adjustments."

    Thanks in advance, I"m posting here because I didn't get responses in the Introductions thread. If this is the wrong area, I'll post where ever is appropriate.

    Also I have no histograms or accurate BLMs, I haven't gotten it out to drive it on the road yet, it is still on jack stands. I think I can do a log of any data I can that way. It would just keep dying out on the road though, and I'm not fortunate enough to have a Dyno.
    Last edited by Blue z28; 2 Weeks Ago at 07:01 AM.

  2. #2
    Fuel Injected! Terminal_Crazy's Avatar
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    1st, Keep your old .bin files and copy it as a new one then alter that one so you can regress the version when you do something the car does not like.
    I save them as LT1_a01 and any logs I keep have the same name.
    Then save LT1_a01 as LT1_a02 and do any mods to this one & reflash.

    You are quoting Steve's site so I presume you have EEHack. If not, look at downloading it and I can look at your datalog file.

    Is you MAF connected?. I'd unplug it for now and put the car into SD(Speed Density) & get you VE table somewhere where it'll run.
    Where are you BLM's sat in cell 16 (idle).
    What MAP value do you have

    They should be around 128. If higher they are adding fuel and lower, pulling fuel.

    Say you have 50 MAP and BLM's (Long Term Fuel Trims) are low around 108 (PCM is trying to pull fuel out but can't go lower) you need to lower your VE Table by at least a similar amount.
    108 /128 (ideal) == 0.84 (84% so you need to scale your VE table down by 84 %.
    I'd normally scale the table across the diagonal multiple time but for now we'll keep it simple....
    Open the lower VE table (should be 400 to 2000 RPM) Select all the table UPTO and including the 1800 RPM (NOT the 2000 RPM line) and scale it by the 84% (smaller) (multiply by 0.84).

    Reflash and see if it idles any better.

    Mitch
    '95 Z28 M6 -Just the odd mod.
    '80 350 A3 C3 Corvette - recent addition.

  3. #3
    Fuel Injected! steveo's Avatar
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    and injectors
    what kind of injectors?

    So it doesn’t idle anymore unless i give it a little gas.
    so this is more likely a diagnostic thread, not a tuning thread.

    your engine should probably run with the original calibration, unless there are things we aren't aware of (like the above injectors). that cam is similar to a lloyd elliot cam and i know it should run and idle 'well enough to drive' without tuning

    verify engine mechanical condition (compression, spark, vacuum, running on all cylinders, etc)

    I just need to know how to tune this thing now.
    just be aware that if you 'fix' a lightly modified lt1 that dies as soon as you let off the throttle by 'tuning' it, you'll end up with a really crappy tune on a broken engine. i can 'tune' an lt1 running on 7 cylinders to run a bit better by screwing around with fueling.

    lets start with what your IAC counts are doing when you let off the throttle

  4. #4
    Electronic Ignition!
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    Quote Originally Posted by Terminal_Crazy View Post
    1st, Keep your old .bin files and copy it as a new one then alter that one so you can regress the version when you do something the car does not like.
    I save them as LT1_a01 and any logs I keep have the same name.
    Then save LT1_a01 as LT1_a02 and do any mods to this one & reflash.
    Yeah, I am doing this just labeled different, stock and v1.x, ect.

    Quote Originally Posted by Terminal_Crazy View Post
    You are quoting Steve's site so I presume you have EEHack. If not, look at downloading it and I can look at your datalog file.
    I downloaded it last night, setup and looked at the interface. After I watch a few youtube videos on it I'll probably LOVE it, just didn't do much without having it connected to the car. I'll do that today.

    Quote Originally Posted by Terminal_Crazy View Post
    Is you MAF connected?. I'd unplug it for now and put the car into SD(Speed Density) & get you VE table somewhere where it'll run.
    Where are you BLM's sat in cell 16 (idle).
    What MAP value do you have
    MAF is currently connected, I havent pulled any BLMs because the car has literally sat for years without a battery. Even if it does have any thing in memory it is from the stock pre cam, LT headers. Or it would more be from the short amounts of time I have ran it on jack stands. I thought they would be misleading until I get more drive time on this build. I'll pull them, first log ever.

    Quote Originally Posted by Terminal_Crazy View Post
    They should be around 128. If higher they are adding fuel and lower, pulling fuel.

    Say you have 50 MAP and BLM's (Long Term Fuel Trims) are low around 108 (PCM is trying to pull fuel out but can't go lower) you need to lower your VE Table by at least a similar amount.
    108 /128 (ideal) == 0.84 (84% so you need to scale your VE table down by 84 %.
    I'd normally scale the table across the diagonal multiple time but for now we'll keep it simple....
    Open the lower VE table (should be 400 to 2000 RPM) Select all the table UPTO and including the 1800 RPM (NOT the 2000 RPM line) and scale it by the 84% (smaller) (multiply by 0.84).
    I saw some where that I need to add 5-8%, This is in the VE vs. RPM vs. Map table? Up to 30 or 35 KPA?

    Quote Originally Posted by Terminal_Crazy View Post
    Reflash and see if it idles any better.
    Mitch
    Last edited by Blue z28; 2 Weeks Ago at 10:52 PM.

  5. #5
    Electronic Ignition!
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    Injectors came with the BBK TB in a package deal, I thought they were larger, they are not. I googled the numbers they are bosch 0280150931 19lb injectors, which might be my problem. I apologized for not finding this out before posting. I'll be looking for new injectors, or get an adjustable FPR to bring it up to 24lb equivalent. My stock ones went bad while sitting for years, It literally poured fuel out of the drivers header on my very first try to start it, and only seemed to be running on a few cylinders. These at least hit on all cylinders.

    IAC counts go to 160 as I let off the throttle slowly.
    Last edited by Blue z28; 2 Weeks Ago at 10:58 PM.

  6. #6
    Electronic Ignition!
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    Here is the first log I have done. I was looking for a way to start the log for the first 85 seconds, so ignore that. The tune is still for 24lb injectors, and I still had the maf connected. I dont know if the codes are current or history. I have started it without the maf connected before, solinoid B, and the coolant sensor I will have to look into. Thanks in advance for your help. Anybody have some good stock injectors? I'll check the classifieds for them ,lol...
    Attached Files Attached Files
    Last edited by Blue z28; 2 Weeks Ago at 04:49 AM.

  7. #7
    Carb and Points! thedave's Avatar
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    where is this tune file? is this a LT1 or a LS? if it is a LT1 computer you mite want to think about running a ostrish 2.0 and tunerproRT to give you live tuning so you can see the effects of what your doing firsthand. I would also invest in a wideband to see what your air fuel is doing. That camshaft has a decent amount of duration i would try to get the car to idle at 950 to 1050 if the car will not do it with the IAC driver turn the throttle body screw in a little. Most of the camshaft i run have like 228/230 duration in them in they can be a pain to tune if you don't do it everyday and also if you don't have a wideband.

  8. #8
    Electronic Ignition!
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    fbodytech_tune_4398.binI was seriously considering getting my AEM wideband n gauge kit. It is an lt1 and a lt1 stock computer, except for the bin (delete A/C, EGR), I've flashed on it. I got to get new injectors. Or tune for these 18.3 Lb injectors, here is my bin. I'll look at getting an ostrich 2.0, I am using TunerproRT 5.0, thinking about getting these, The said they would warranty for pattern and imbalance. https://www.ebay.com/i/231405559001?...evt=1&mkcid=28
    Or someone has some stockers in utah. Opinions?
    Attached Files Attached Files
    Last edited by Blue z28; 2 Weeks Ago at 11:15 PM. Reason: wrong bin

  9. #9
    Fuel Injected!
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    Whatever injectors you buy, you must get the full data package: flow rate, voltage offsets and short pulse adders; otherwise the car will not behave well at idle or part throttle. And you'll need to know what fuel pressure your fuel system is producing for optimal data; the stock LT1 regulators tend to drift high over time. If you need more help, send me a PM. I can help, and I have a set of much better injectors than the ones you listed.

  10. #10
    Fuel Injected!
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    In addition to everything sherlock9c1 said above,
    you're using 4.3L L99-sized fuel injectors on a 355 cubic inch V8 which should be using 24lb per hour injectors minimum.

    sherlock9c1, got a set to spare for Blue Z28?
    THEY are NOT Lying to You. You are NOT Lying to Yourself. You ARE Being Lied to - BY Your Self
    The Last Psychiatrist, aka … Alone …


  11. #11
    Electronic Ignition!
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    Quote Originally Posted by sherlock9c1 View Post
    Whatever injectors you buy, you must get the full data package: flow rate, voltage offsets and short pulse adders; otherwise the car will not behave well at idle or part throttle. And you'll need to know what fuel pressure your fuel system is producing for optimal data; the stock LT1 regulators tend to drift high over time. If you need more help, send me a PM. I can help, and I have a set of much better injectors than the ones you listed.
    So I have a extra fuel pressure regulator I cut apart to make a adjustable one out of. I am still working out how, and gotta find just the right parts at Home Depot or Lowe’s, anyway I’ll let you know how it turns out.

  12. #12
    Fuel Injected! steveo's Avatar
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    Quote Originally Posted by thedave View Post
    where is this tune file? is this a LT1 or a LS? if it is a LT1 computer you mite want to think about running a ostrish 2.0 and tunerproRT to give you live tuning so you can see the effects of what your doing firsthand.
    you've never actually done that with a 1994+ lt1 ECM. being that its a dual board soldered PLCC flash ecm it's not really a good option at all.

    if the car will not do it with the IAC driver turn the throttle body screw in a little.
    no, the lt1 hates idle air through the plates. it's one of those engines that needs the plates to be closed. if the iac runs out of room and you need more air, you enlarge the bypass hole rather than cracking open the throttle plates to get more even cylinder flow through the idle passages in the plenum.

  13. #13
    Fuel Injected! steveo's Avatar
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    Quote Originally Posted by Blue z28 View Post
    So I have a extra fuel pressure regulator I cut apart to make a adjustable one out of. I am still working out how, and gotta find just the right parts at Home Depot or Lowe’s, anyway I’ll let you know how it turns out.
    generally the change in injector flow rate isn't just a matter of 25% more pressure equals 25% more flow. it's closer to the square root of the difference

    SQRT(68/43.5) * 19 = 23.75PSI

    you'd theoretically need somewhere around 68 psi of fuel pressure to turn your 19lb injectors into 23.75lb ones. that's a nearly 25PSI gain!

    this is not a great approach and your injectors will probably have unknown issues with pressure so far outside their normal range

    you should stop trying to avoid buying new ones. you put all this work into the engine and you want it to run properly and be reliable. you also want to learn to tune, so you want your injectors and all sensors to be in a totally predictable condition

  14. #14
    Electronic Ignition!
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    Quote Originally Posted by steveo View Post
    generally the change in injector flow rate isn't just a matter of 25% more pressure equals 25% more flow. it's closer to the square root of the difference

    SQRT(68/43.5) * 19 = 23.75PSI

    you'd theoretically need somewhere around 68 psi of fuel pressure to turn your 19lb injectors into 23.75lb ones. that's a nearly 25PSI gain!

    this is not a great approach and your injectors will probably have unknown issues with pressure so far outside their normal range

    you should stop trying to avoid buying new ones. you put all this work into the engine and you want it to run properly and be reliable. you also want to learn to tune, so you want your injectors and all sensors to be in a totally predictable condition
    Thank you I’ve been looking for that formula, I saw it in another thread and couldn’t find the thread again. I’ve read somewhere increases in fp result in injector open n closing timing issues. I made an offer On those injectors at $54 I didn’t think they would take and they did. I’ll get them n if I have any issues I’ll send them back. I know how to put in the 42# scaler, but how do I tune for injector timing wit these specs;

    Features
    · Quantity: 8 Fuel Injectors
    · Condition: 100% BRAND NEW
    · Design: Bosch GEN III EV1 Style Fuel Injector
    · O-Rings Included: Yes, preinstalled
    · Injector Design: Metal & composite plastic
    · Nozzle Design: 1 hole disc
    · Connector Type: EV1
    · Filter Design: Basket filter design at inlet
    · Spray Pattern: 15 Degree Spray Cone


    Technical Data
    · Coil Resistance: 12 Ohms / High Impedance
    · Static Flow Rate: 42 lb/hr = 440 cc/min @ 43.5PSI ( 300kPa )
    · Gain: 0.12ms/MG
    · Offset: 0.055ms
    · Turn on time @ 14VDC: 1.14ms
    · Turn off time: 0.85ms @ 300KPa
    · Amperage: 1.0 Amps
    · Pressure: Min 30PSIG/ Max 100PSIG
    · Length: 3" (74mm)
    · O-Ring Diameter: 14.5mm

    What are the precise terms for editing I saw a “injector Offset vs. voltage” I think might be it? or link to a good thread.
    Last edited by Blue z28; 2 Weeks Ago at 07:19 PM.

  15. #15
    Fuel Injected! steveo's Avatar
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    you need injector offset vs voltage data to fill the table
    most injector data sheets have that
    i see the specs above have opening time @14v which is good but would be nice to find the complete table
    the points in the table might be at different voltages from your injector offset table
    to interpolate the values easily you can use a cubic spline function
    google cubic spline tool

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