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Thread: Few questions on my 1st LT1 tune

  1. #1
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    Few questions on my 1st LT1 tune

    I have started my first LT1 tune; downloaded my stock bin the other day, and have been slowly reading into and modifying small stuff like fans, did the BLM PE WOT patch etc;

    I had a few questions about my stock bin; It had a 0 for the Injector Flow, Cylinder Volume, and the speedometer seemed to be way way off from the spreadsheet's calculations.... is this normal? I noticed so many things were way different with the 95 z28 stock bin compared to my car (other then the trans stuff, I know they are way different anyway).

    Secondly, I was wondering about tuning for CAI; Cat-Back; 3500 Stall + Shift Kit.... I will change PE WOT AFR once my wideband comes in, and add a couple degrees of timing throughout but the big question I have is tuning for the stall and shift kit.... I have only had the car for a few weeks but it definitely slaps the rev limiter leaving first, and I got damn close in second even with letting out. I have changed shift points, but I have read so many opinions about changing line pressure when you already have a shift kit; The trans has only 7,000 miles on it since the build, I really do not want it to shift "harder" but faster.. What should I look into to shorten time between shifts?

    Also, which values need to modified for a stall that big? Can I up my main line pressure to help the stall? What about TCC I have no experience with Automatics so I am completely lost there.

    Sorry for all the q's hope I can get some help.... I am worried about flashing this bin before I get an answer about those 0's.

    My edited bin is here > http://www.gearhead-efi.com/Fuel-Inj...7&d=1408227723
    My stock 1994 Camaro Z28 A4 Bin is attached below, for anyone who may want to look at it for me or need it!
    Attached Files Attached Files

  2. #2
    LT1 specialist steveo's Avatar
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    Quote Originally Posted by JustinSEO View Post
    I had a few questions about my stock bin; It had a 0 for the Injector Flow, Cylinder Volume, and the speedometer seemed to be way way off from the spreadsheet's calculations.... is this normal? I noticed so many things were way different with the 95 z28 stock bin compared to my car (other then the trans stuff, I know they are way different anyway).
    that would likely be the EEB revision. best to start with a stock EE bin and flash that so everything works like planned, or use tunercat's EEB definition (there's no tunerpro EEB definition afaik)

  3. #3
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    I don't have a stock EE bin though, I only have my bin; I've not been able to find another 94 z28 A4 bin anywhere...

    So you say i should flash with a new bin other then my stock one edited?

  4. #4
    LT1 specialist steveo's Avatar
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    well, you certainly can't edit your existing bin with tunerpro... unless someone writes a proper EEB definition for it. if you want to use your existing bin you'd have to use tunercat with his EEB definition.

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    Well I bricked my PCM good thing I bought a spare before all this... I did a EE flash and went for a drive, the speedo was maxing out and hence the values were different from my EEB bin I plugged them in there and attempted another flash, as soon as it finished I turned car off for 30 seconds then key back on and fans kicked in full speed without a high temp I knew right off... It would crank and idle but not take any gas. Now I'm gonna have to tune around DTC 83 and edit everything I can tell shift points are way different. My converter locks up ok and it's running but BLM were down around 112-115 on decel and below 128 on WOT


    don't think I'll reflash until I can send my spare one out to be repaired, I daily this car.
    Last edited by JustinSEO; 08-20-2014 at 07:46 AM.

  6. #6
    LT1 specialist steveo's Avatar
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    blms always show a bit low in cell 17 (decel), 'specially on a modified LT1, that's alright.

    in EE, the trims should never be below 128 in power enrichment mode (WOT) .... unless you run a vette bin which i think will hold those trims down to 120 but im not 100% on that.

  7. #7
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    I will have to watch my data log again and verify, but I can definitely tell that there is something going on with that 95 z28 flash... The PCM was a Cardone Reman unit, unsure of what all they do with them. I had to move my knock module over, and then i read the PCM to check it out and make sure it was populated with data and then i data logged on first fire up... It'll run just doesn't perform like my old tune did.

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    Why not grab any 94 auto bin and basically copy everything that is different from your original bin over to it? Well, only copy the parts that are correct from the EEB bin.

    I wouldn't try switching a manual bin to an auto bin using the auto/manual flag, I recall there was a question of that flag being correct that was not fixed.

    Also, be careful of the transmission pressure scalar. Raising the max pressure scalar does not increase the line pressure. Read the comments from sherlock9c1 on the transmission line pressure here.

    http://www.gearhead-efi.com/Fuel-Inj...cess-curing-it

  9. #9
    LT1 specialist steveo's Avatar
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    I wouldn't try switching a manual bin to an auto bin using the auto/manual flag, I recall there was a question of that flag being correct that was not fixed.
    that has been fixed and verified working in the latest revision of EEX on either my site (resfilter.net) or the sticky thread on this site.

    i took my manual bin, switched the flag, sent it to an auto guy, it's been workin' fine.

  10. #10
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    Good to hear, I was thinking the bit for that flag wasn't known.

    In that case any 94 bin would work as a starting point.

  11. #11
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    I would like to get a 94 a4 bin and flash it I just don't need another bricked pcm. I was thinking of getting another locally for 60$ and trying to flash it.. My car is running for now and it has to run because it's a daily.. I just hope I'm not doing any damage with a 95 vert pcm and flash in my 94..

    Definitely gonna read up more on the dos and donts. I have EEx and I will be using it to edit a stock 94 EE bin if I can find one anywhere.... I haven't seen one online that still works.

  12. #12
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    I'm not sure what you did during programming to brick your PCM, but you should be able to flash any $EE bin into it without issue.

    There is a 94 T/A bin on the site you could start with.

  13. #13
    LT1 specialist steveo's Avatar
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    sometimes flash memory just dies. it's not super awesome flash memory

    definitely get a spare ecm

    but keep in mind i flashed mine at least 1000 times, and before i had it, it was an exchange ecm from a tuning shop so godknows how many times it'd been flashed before.

  14. #14
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    Gosh, my current tune is trash compared to my old one.... The car is running higher RPM maybe from the TCC problems; The speedo is way off, the BLMs are all over....

    Someone link me to a stock 94 bin? I have been looking for one....

    Here is a copy of my datalog, if you wish to take a look plz do; seems like the car is running kind of rough.
    Attached Files Attached Files

  15. #15
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    I can lend a bit of advice on transmission tuning as I have had LT1/4L60Es for a long time.

    1. The 4L60E has no built-in pressure sensor to provide feedback to the PCM, so all it can do is gauge shifts based on time. Just like you bought a wideband, buy a transmission pressure gauge and drive around for a few weeks with the gauge strapped to your windshield wiper like a hood tach so you can get an idea of what it's really doing pressure-wise. Ebay seller cmbclalb sells a good one that I've used for a long time. A healthy 4L60E will have around 70psi at idle in Park, Neutral or Drive, and climb to around 150psi in reverse. You should see over 200psi at WOT at some point in 1st gear.
    2. Think of line pressure tuning as two separate regions; during shifts, and between shifts. If the trans is not slipping in gear, then leave the line pressure tables alone and ONLY reduce the "Shift time (sec) vs. TPS vs. shift." In the last LT1/4L60E I tuned, the WOT shifts were perfect at 0.600 sec for 1-2 and 0.875 sec for 2-3. Leave the 3-4 shift at 0.00 seconds because the 4th gear apply piston is small and needs no softening. That 1-2 shift value gave me just a slight chirp from the rear tires. I tried 0.400 sec but it was too harsh and barked the tires. 0.800 sec wasn't firm enough and was actually cutting pressure during the shift according to Datamaster.
    3. The 4L60E is a bit of a hybrid transmission in that the shift solenoids command the START of the shifts, but the actual shifting is still completed by hydraulic valves, unlike something like the Chrysler 41TE where the solenoids directly fill the hydraulic circuits with no additional valves. Sometimes these shifts take a long time to complete, so if you're hitting the rev limiter and you have sufficient line pressure during the shifts, you need to reduce the shift MPH to get the shift to complete on time. A looser converter, numerically lower rear axle, more engine torque, and more vehicle weight will all exacerbate this late shift behavior.
    4. Shifting harder IS shifting faster, and vice versa. It's really a balance point. For modded vehicles, the only way to get your 4L60E shifting perfect assuming it's in good mechanical health is to dial it in over the course of a datalogging/tuning session, or in my case, a road trip.
    5. No need to up line pressure with a looser converter unless you think it's slipping. The easiest way to do this is to reduce the "maximum line pressure" scalar 5-10% which will give you 5-10% more pressure across the board at part throttle, but it will NOT give you any more at WOT once the sum of the line pressure tables equals or exceeds the scalar.

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