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Thread: Running way to lean in cold open loop. How do I fix it?

  1. #1
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    Default Running way to lean in cold open loop. How do I fix it?

    As you can see when I give it a little throttle it runs lean. How do I go about fixing this? As you probably figured out I have a LC-1 wideband.

    I messed up and did not record the feedback from the Lc-1 but it mostly follows the commanded fuel.

    The second log has pid's for Auto Ve and it shows the LC-1.

    MYfirebird start prog from doug 12-10-07.tun

    first cold start log bird.efi

    SD lean part throttle cold.efi

    Im pretty sure I have to change my b3605 table but why dose it only use this table with throttle? it snaps back to good fuel ratio when their is no throtle. Dose it get its idle fuel ratio from another table?
    1999 TA Ram air 6spd

    LSX 454, Patriot Performance Heads 72cc stage 3, LS6 Intake, stock ported throttlebody, American racing 1 7/8" headers, Magnaflow Cat back, Cut out, Nasty Performance fuel system, 11.44-1 comp ratio, no cats no air, 60 lb injectors, 58 psi fuel, comp cams, gross valve lift in .613 ex .596 durration @ .050 in 252 ex 262 Lobe sep 114 Intake Centerline 112. hartlandsharp 1.7 roller rockers.
    490 hp 494flbs on current tune. Better top end comming soon.

  2. #2
    Joe (Moderator) joecar's Avatar
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    Hi 1HotBird,

    The left half of your B3605 contains EQ 0.702-0.821 (~AFR 17-20)...
    you should change these cells to EQ 0.99 or 1.01 (AFR 14.78 or 14.49) .

    The PCM uses the richer of B3605 and B3618 [when PE is enabled] during open loop... in your case, PE is not enabled, so the PCM looks at B3605... you can see this if you enable scantool->tunetool PID linking.

    In your log, when AFR goes to 18+, the FTC # is 22 which is supposed to indicate WOT, but your TP is only 5-6%... I can't tell why, but the PCM goes to FTC # 22 for some reason.

    Cheers,
    Joe

  3. #3
    Unknown Zone TAQuickness's Avatar
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    IIRC, when in OLSD, you only have 3 FTC's: idle, WOT, and I can't remember the other one off the top of my head. Been a long time since I've done any tooning [sic] that required monitoring of the FTC's.

  4. #4
    Senior Member SV8346's Avatar
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    From what i can see from the logs there is a few problems with this tune, first is B3605 is extremely lean on the whole left side of the table. Second problem i have found is the timing tables (B5913 and B5914) are very erratic, try smoothing out the timing tables a bit and also drop your base timing(B5932 and B5933) down and idle timing down a bit, your trying to give it 35 degrees timing at idle which is way to high IMO.
    2016 RG Colorado 2.8TD

  5. #5
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    Just a question but someone mentioned it might be set lean because I have alot of overlap in the cam? Can the overlap fool the narrow and or the wideband into a false lean reading?

    What is FTC #22??? (Sorry Im new)
    Also How do I do this, enable scantool->tunetool PID linking.???

    Thanks

    Quote Originally Posted by joecar
    Hi 1HotBird,

    The left half of your B3605 contains EQ 0.702-0.821 (~AFR 17-20)...
    you should change these cells to EQ 0.99 or 1.01 (AFR 14.78 or 14.49) .

    The PCM uses the richer of B3605 and B3618 [when PE is enabled] during open loop... in your case, PE is not enabled, so the PCM looks at B3605... you can see this if you enable scantool->tunetool PID linking.

    In your log, when AFR goes to 18+, the FTC # is 22 which is supposed to indicate WOT, but your TP is only 5-6%... I can't tell why, but the PCM goes to FTC # 22 for some reason.

    Cheers,
    Joe
    1999 TA Ram air 6spd

    LSX 454, Patriot Performance Heads 72cc stage 3, LS6 Intake, stock ported throttlebody, American racing 1 7/8" headers, Magnaflow Cat back, Cut out, Nasty Performance fuel system, 11.44-1 comp ratio, no cats no air, 60 lb injectors, 58 psi fuel, comp cams, gross valve lift in .613 ex .596 durration @ .050 in 252 ex 262 Lobe sep 114 Intake Centerline 112. hartlandsharp 1.7 roller rockers.
    490 hp 494flbs on current tune. Better top end comming soon.

  6. #6
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    Can you break this down for the new guy? IIRC,OLSD,3 FTC's???
    Thanks

    Quote Originally Posted by TAQuickness
    IIRC, when in OLSD, you only have 3 FTC's: idle, WOT, and I can't remember the other one off the top of my head. Been a long time since I've done any tooning [sic] that required monitoring of the FTC's.
    1999 TA Ram air 6spd

    LSX 454, Patriot Performance Heads 72cc stage 3, LS6 Intake, stock ported throttlebody, American racing 1 7/8" headers, Magnaflow Cat back, Cut out, Nasty Performance fuel system, 11.44-1 comp ratio, no cats no air, 60 lb injectors, 58 psi fuel, comp cams, gross valve lift in .613 ex .596 durration @ .050 in 252 ex 262 Lobe sep 114 Intake Centerline 112. hartlandsharp 1.7 roller rockers.
    490 hp 494flbs on current tune. Better top end comming soon.

  7. #7
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    First things first I need to get my mind wraped around the fueling side of the computer, then I will move on to the Spark.

    Ive been told that because of the overlap in my cam it has a "natual EGR" effect, there for needing more advance at lower RPM's?? Can anyone tell me if this is true????

    Quote Originally Posted by SV8346
    From what i can see from the logs there is a few problems with this tune, first is B3605 is extremely lean on the whole left side of the table. Second problem i have found is the timing tables (B5913 and B5914) are very erratic, try smoothing out the timing tables a bit and also drop your base timing(B5932 and B5933) down and idle timing down a bit, your trying to give it 35 degrees timing at idle which is way to high IMO.
    1999 TA Ram air 6spd

    LSX 454, Patriot Performance Heads 72cc stage 3, LS6 Intake, stock ported throttlebody, American racing 1 7/8" headers, Magnaflow Cat back, Cut out, Nasty Performance fuel system, 11.44-1 comp ratio, no cats no air, 60 lb injectors, 58 psi fuel, comp cams, gross valve lift in .613 ex .596 durration @ .050 in 252 ex 262 Lobe sep 114 Intake Centerline 112. hartlandsharp 1.7 roller rockers.
    490 hp 494flbs on current tune. Better top end comming soon.

  8. #8
    Senior Member SV8346's Avatar
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    Quote Originally Posted by 1Hotbird
    Also How do I do this, enable scantool->tunetool PID linking.???

    Thanks
    Open TUNE tool then click on "EDIT" up the of the page then click on "PROPERTIES" then in the properties window that opens click on the "SCANNER" tab, there you will see "Highlight scan tool selection in tuning tool maps". Make sure this is selected.

    From there on when you have scan tool open and tune tool by putting the cursor on a select point in the log it will highlight that point in the tune.

    Quote Originally Posted by 1Hotbird
    Can you break this down for the new guy? IIRC,OLSD,3 FTC's???
    Thanks
    IIRC=If I Remember Correctly
    OLSD= Open Loop Speed Density
    FTC= Fuel Trim Corrections (I think )

    Ok to get you head wrapped around the fuel side of things first then i would strongly suggest you richen up the whole left side of your mixture map(B3605) before you lunch your engine.

    Upload this tune and give this a go, i think you'll find it will idle allot smoother and also it wont run anywhere near as lean as what it was.
    Attached Files Attached Files
    Last edited by SV8346; December 23rd, 2007 at 05:40 PM.
    2016 RG Colorado 2.8TD

  9. #9
    Joe (Moderator) joecar's Avatar
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    From the scantool manual pdf (page 137):

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