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Thread: 2 bar tune for Turbo LT1 F-body possible with '93 ECM? DA3

  1. #61

  2. #62
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    Quote Originally Posted by steveo View Post
    added kur4o's patches to my patches for you. just patch the patch and let us know how she goes
    Hells yeah. Will give it a go hopefully tomorrow.

    Many thanks again to you both !
    J. Moen
    91 Camaro - NASA American Iron Road Racer #91 "The Menace", carb'd 350, FloTek heads, "because racecar"
    91 Camaro RS - '93 LT1 /T56 swap, 224/224, 60lb Siemens, garage ported heads, VS racing 78/75 turbo, Intercooled

  3. #63
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    So far so good . . .

    Well fellas, we have some success so far! I am indebted to you both, there was no way in the world I was going to figure that out. I still don't understand what you did there, but it seems to work great. I didn't drive real far, but did the loop that would always reset it a couple times before, and this time she's solid.

    Strangely enough, the Baro does update at key on, obviously not a bad thing at all, but then no amount of romping seemed to phase that baro setting.

    Yahoo, let the real tuning begin, I hope.
    J. Moen
    91 Camaro - NASA American Iron Road Racer #91 "The Menace", carb'd 350, FloTek heads, "because racecar"
    91 Camaro RS - '93 LT1 /T56 swap, 224/224, 60lb Siemens, garage ported heads, VS racing 78/75 turbo, Intercooled

  4. #64
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    Well tonight was a little different story. I adjusted the spark tables, and a bit on the lower VE table, and was going for a test drive.

    Then I notice cruising AFR seems to be quite lean and she's surging some. WTH? Check the scanner and she's updated to 10.35kPa again (happened a week and half ago or so)! Cycling key on / off did nothing to change it. So just went back home. Thought maybe it was the tune somehow, so tried yesterday's .bin file, and the 10.35 remained.

    The only way I could get well from it was to try an unpatched tune. Load it, key on, then baro matched the current MAP reading, which is no surprise.

    So then I loaded the latest tune back in, and it stayed put at 54.36 but I didn't drive it to try it out and see if it held or not. Guess I'll try that again tomorrow.

    What's odd is that when I loaded the new patch last night, the BARO reading updated from in the 60's, down to 54.xx. It seemed to update at key on. BUt then tonight once it pulled 10.35 it wouldn't update again at key on.

    Is it possible the ECM just saw a glitch in that sensor or something at the wrong time? Also, a common theme is it seems to happen after an adjustment in the .bin and a chip swap. Maybe it just wasn't seated in the ZIF or something?
    Last edited by hotrodf1; 10-11-2018 at 05:19 AM.
    J. Moen
    91 Camaro - NASA American Iron Road Racer #91 "The Menace", carb'd 350, FloTek heads, "because racecar"
    91 Camaro RS - '93 LT1 /T56 swap, 224/224, 60lb Siemens, garage ported heads, VS racing 78/75 turbo, Intercooled

  5. #65
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    There is an error. Now baro never updates from memory. The value had cleared when you removed power from pcm.

    Tell me what fixed value you want for baro. Do you want it to update at ign on engine off. There is also 6 tables that are baro related modifiers. If you set the baro at 55 kp these tables will always read the lowest position.

    Patching anything will not be that hard. Just need to know how do you like the PCM to behave. Do you know some other PCM from that era that use 2 bar map sensor and turbo setup. I can copy the conversion from raw map to baro, so you don`t have to lose these built in baro corrections.

    There is another conversion from raw baro 3f to some scaled map baro value stored at byte_0158. byte_0158 is used for baro table lookups.

  6. #66
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    Quote Originally Posted by kur4o View Post
    There is an error. Now baro never updates from memory. The value had cleared when you removed power from pcm.
    Firstly, sorry for any ignorance, I'm pretty new to tuning EFI.

    I did not pull power from the ECM to swap chips. I haven't been - just been obviously having the key off while swapping the chip. Is this a bad idea? Also, I have pulled power via battery and/or ECM fuse, and even so the Baro reading remains. Seems odd, but pretty sure this is what I have observed.

    Tell me what fixed value you want for baro. Do you want it to update at ign on engine off. There is also 6 tables that are baro related modifiers. If you set the baro at 55 kp these tables will always read the lowest position.
    I think just setting baro to a fixed value of 55 will be all I'd need. Would be nice if it updated at key on, but that's not totally necessary. I'd be happy if it would just stay put at 55kPa.
    What do you mean by "read lowest position?" Use the minimum value from the table?

    Due to the change in baro from 104 to 55, I had to run the cylinder volume to maxed out, and also use higher values in the open loop %change vs. MAP table to get enough fuel rolling. Took a bit of time to figure out how far I had to go there, but at this point it's somewhat close. So not sure how much baro modifier stuff I should fool with?

    Patching anything will not be that hard. Just need to know how do you like the PCM to behave. Do you know some other PCM from that era that use 2 bar map sensor and turbo setup. I can copy the conversion from raw map to baro, so you don`t have to lose these built in baro corrections.
    The only thing I know of is maybe the Cyclone / Typhoon trucks. I think that's what the MAP sensor is from. But they are 6 cyl. of course. If you were able to use some conversion there to the LT1, I guess my cylinder volume and other table would need to go back to a more "normal" setting?

    There is another conversion from raw baro 3f to some scaled map baro value stored at byte_0158. byte_0158 is used for baro table lookups
    So by changing the scaling there, it would alter what values get pulled from the baro table lookups then?
    J. Moen
    91 Camaro - NASA American Iron Road Racer #91 "The Menace", carb'd 350, FloTek heads, "because racecar"
    91 Camaro RS - '93 LT1 /T56 swap, 224/224, 60lb Siemens, garage ported heads, VS racing 78/75 turbo, Intercooled

  7. #67
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    Even you are new to efi your are learning fast. All your assumption are correct.

    Try this patch. It updates baro once at ign on only. The value is converted to display accurate baro reading. I assume 2 bar map sensor outputs $80 at 1 bar and $ff at 2 bar. You can check the reading with altitude meter to confirm that the conversion is correct.
    Attached Files Attached Files

  8. #68
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    Quote Originally Posted by kur4o View Post
    Even you are new to efi your are learning fast. All your assumption are correct.

    Try this patch. It updates baro once at ign on only. The value is converted to display accurate baro reading. I assume 2 bar map sensor outputs $80 at 1 bar and $ff at 2 bar. You can check the reading with altitude meter to confirm that the conversion is correct.
    Should say too, the baro reading hasn't gone nuts to 10.35 ever since it happened that last time. Odd.

    Anyhow, I'll give it a try. Would be nice to get the tables back in line.

    To make sure I don't totally foul this up - should I start with the values for cylinder volume and open loop % change vs. MAP that I had used in my previous 1 bar MAP tune? And then obviously progress slowly into boost and she what she does?
    J. Moen
    91 Camaro - NASA American Iron Road Racer #91 "The Menace", carb'd 350, FloTek heads, "because racecar"
    91 Camaro RS - '93 LT1 /T56 swap, 224/224, 60lb Siemens, garage ported heads, VS racing 78/75 turbo, Intercooled

  9. #69
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    Tried the new patch last night. The conversion seems pretty close, close enough I do believe. ECM reported 99.5 kPa or so. However, I ended up having to still keep the cylinder volume maxed out and the % change vs. MAP table (I'm running open loop only) at the same values as previous tune to get the AFR where it should be. Just from what I observed, it seems that it's still pulling from the minimum result from the baro correction table.

    I'm not sure what trouble that will cause. Do we keep trying to fix it, or let it be?
    J. Moen
    91 Camaro - NASA American Iron Road Racer #91 "The Menace", carb'd 350, FloTek heads, "because racecar"
    91 Camaro RS - '93 LT1 /T56 swap, 224/224, 60lb Siemens, garage ported heads, VS racing 78/75 turbo, Intercooled

  10. #70
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    Actually engine needs more fuel with lower baro readings. It is more efficient I guess.

    If you can`t add more air in the equation, your choice is to add more AFR. As a last step play with the injector fuel flow scalar.

    Can you find a bin,xdf,adx of that cyclone turbo car.

  11. #71
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    I was thinking the requirement for the higher values, was due to the fact that the ECM is calculating less PW because there is much less air density. Less air should need less fuel, so to make up for that in the calculation, I gotta swing these values way high to compensate.

    Nevertheless, I have the tune working OK right now I think. So far the baro update deal seems to be solved. It's getting fun: she's loosing traction at about 50mph, with only 5psi haha.
    J. Moen
    91 Camaro - NASA American Iron Road Racer #91 "The Menace", carb'd 350, FloTek heads, "because racecar"
    91 Camaro RS - '93 LT1 /T56 swap, 224/224, 60lb Siemens, garage ported heads, VS racing 78/75 turbo, Intercooled

  12. #72
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    Typhoon / Cyclone is $58 it seems. There's a thread with all the versions of it etc., several to choose from.
    http://www.gearhead-efi.com/Fuel-Inj...information-58
    J. Moen
    91 Camaro - NASA American Iron Road Racer #91 "The Menace", carb'd 350, FloTek heads, "because racecar"
    91 Camaro RS - '93 LT1 /T56 swap, 224/224, 60lb Siemens, garage ported heads, VS racing 78/75 turbo, Intercooled

  13. #73
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    Just a quick update: tuning / driving has been going relatively well. I had to take out a whole lot of accell enrich value due to the extra fuel I guess that the open loop tune throws in. Through many iterations, I had to cut them in half to get a reasonable throttle response, but it's much better now.

    I do have one issue that I haven't figured out - every now and then, the car seems to lean way out all over. For example, the idle is normally in the 13.6-14.0 range, kinda moves around some. It stays this way most of the time, but sometimes it will go straight to about 15.3 or so and always return to that for the rest of the run. Then the next day, it seems to be fine and back to normal. If I don't catch it when it does this lean out, it will not run well under boost (duh!) and pulls lots of timing and all. So far I've been lucky it hasn't been hurt I suppose.

    So now I'm going to watch the PW real close when it does this again, and see if it's actually changing the PW or if there is something else going on (like fuel pressure or ???). I've got a FP gauge under the hood too, so if it does it again, I can also view that to see if something wonky is going on with the regulator. ALso will watch the MAP reading / density reading to verify something hasn't gone wrong there.

    Fuel system is stock third gen to the motor, then stock LT1 to the rails etc. The fuel pump upgrade is Quantum Fuel Systems pump replaced the original in tank. I forget now what the flow was, but did a fair amount of research and this should be plenty.

    Against all recommendations, I have not replaced / added to the fuel pump power circuit, as most guys seem to do.
    J. Moen
    91 Camaro - NASA American Iron Road Racer #91 "The Menace", carb'd 350, FloTek heads, "because racecar"
    91 Camaro RS - '93 LT1 /T56 swap, 224/224, 60lb Siemens, garage ported heads, VS racing 78/75 turbo, Intercooled

  14. #74
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    I just wanted to let anyone interested in this patch I use it in my sts 2bar boosted tune and it does work I want to gives thanks for all the hard work you've done it wouldnt be possible for me to tune my on without your hard work

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