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Thread: slow off the line

  1. #1
    Fuel Injected! PJG1173's Avatar
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    slow off the line

    I have most of my tune nailed down. AFR's are with in .3 (open loop). I've tweeked TPS and MAP AE so I don't see any lean spikes when hitting the throttle from different positions. I still get a slight lean after completing the 1 > 2 shift but its not bad. one thing i haven't had much luck getting rid of is its lazy throttle response off the line. if I nail it from a dead stop I can hear the "whop" throttle opening, it kind of rolls forward no learch or anything, then takes off like a rocket. there is no stumbling, poping, or anything of the sort. AFR goes to 11.1 when I stomp it from a dead stop. It almost seams like not enough timing, but I haven't figured out where I could add timing to compensate for this. anyone have any ideas? what should I be looking for in the logs?
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    Fuel Injected! fasteddi's Avatar
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    Hu, well id think you may need more timing. What mask are you running?

    I had a issue like that but I lowered the RPM multiplier for PE mode for my rpms that I had issue with. But also I have a auto so theres no delay in shifts. Just my 2 cents. And im on a $59 mask. But who knows just look at the datalogs and check your KPA and RPM and such and see where you need timing, and hopefully it doesnt overlap other times when you need more AE.
    Last edited by fasteddi; 04-11-2012 at 04:59 AM.
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    Fuel Injected! PJG1173's Avatar
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    I'm running $0D. Looking through my bin I don't see a RPM multiplier for PE mode. IDK maybe I just need to give it more pe timing down in the lower rpms.
    87 4Runner, 15" spring lift, 3" body, chevy vortec 355, 5.29 gears, 38.5x15.5x15" Boggers, 280hr, 16168625 running $0D
    93 S10, 36x12.5x15 TSL's, custom turbo headers, 266HR cam, p&p vortec heads, $0D Marine MPFI with 8psi boost.
    05 Silverado, 2' lift, 4" exhaust, Bully Dog programmer,

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    RIP EagleMark's Avatar
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    Spark advance tables "PE Spark vs. RPM"

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
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    Fuel Injected! JeepsAndGuns's Avatar
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    If its going to 11.1 afr when you stomp it, thats kinda rich, you sure its just not just giving it a momentary flood?
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    If its going to 11.1 afr when you stomp it, thats kinda rich, you sure its just not just giving it a momentary flood?
    Too much acceleration enrichment can do that. No amount of timing change will improve the situation. AE should be adjusted so you get the minimum necessary. Additionally, the lean condition after 1-2 shift might indicate a lean VE map which is being covered by AE. Sometimes it's tricky to separate VE tuning from AE tuning but it can be done.
    Last edited by 1project2many; 04-11-2012 at 05:09 PM.

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    RIP EagleMark's Avatar
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    Quote Originally Posted by 1project2many View Post
    Sometimes it's tricky to separate VE tuning from AE tuning but it can be done.

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
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  8. #8
    Fuel Injected! PJG1173's Avatar
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    Quote Originally Posted by 1project2many View Post
    Too much acceleration enrichment can do that. No amount of timing change will improve the situation. AE should be adjusted so you get the minimum necessary. Additionally, the lean condition after 1-2 shift might indicate a lean VE map which is being covered by AE. Sometimes it's tricky to separate VE tuning from AE tuning but it can be done.
    I think this is what is happening, but i'm unsure how the TPS AE table works. for the 1-2 shift i've been little by little adding map ae to get rid of the lean spot. privious logs show timing at launch to be 20* and stays there until 2100 rpm.
    I was going to get a new log of a hole shot last night but quickly relized when I got to a back road near my house (as the truck started to spit and sputter) that someone siphoned 1/2 a tank of gas out of my truck and to add insult to injury I forgot my wallet at the house so I couldn't even stop to get gas!
    87 4Runner, 15" spring lift, 3" body, chevy vortec 355, 5.29 gears, 38.5x15.5x15" Boggers, 280hr, 16168625 running $0D
    93 S10, 36x12.5x15 TSL's, custom turbo headers, 266HR cam, p&p vortec heads, $0D Marine MPFI with 8psi boost.
    05 Silverado, 2' lift, 4" exhaust, Bully Dog programmer,

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