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Thread: high map on hwy

  1. #31
    Fuel Injected! PJG1173's Avatar
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    Quote Originally Posted by EagleMark View Post
    At steady TPS 1900ish RPM 90ish MAP 60 MPH no AE or PE and WB AFR swings about 13.9 to 14.9ish? Never steady?
    I don't think I've ever seen the wb steady. I could slow down the sample rate that may calm it down some.
    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,

  2. #32
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    Soft miss fire I believe is same as a lean misfire in the sense it is firing but not combustion fuel properly. Lean misfire is just fuel mixture to lean to light off, or light and not burn completely.

    It's possible, we are kind of breaking new ground here of things experienced dyno guys don't like to talk about, at least around here. If you read these statements below from my LC-1 WB it says it could be to fast and slower will be a better average. But then again it says it can measure individual pockets of gas... which might be where it's at now and showing one cylinder off? With TBI or a carb in a wet intake manifold the mixture is not going to be same in every cylinder like dry intake manifold MPFI.
    The normal state of the analog outputs is to update the outputs every time the LC-1 takes a new measurement. The LC-1 is fast enough to distinguish individual pockets of exhaust gas. For many applications this will be too fast. The advanced programming allows to set the analog out update speed.
    When setting the LC-1 to the slower response speed settings the measured mixture data will be averaged over the response time setting before being output.
    1) An exhaust leak will allow oxygen to enter the exhaust stream and therefore will measure leaner than the engine is actually running. For correct measurement, airleaks in the exhaust MUST be prevented under all circumstances.
    2) Missing ignitions (where the air-fuel mixture does not ignite) also pump unburned oxygen into the exhaust and cause the LC-1 to measure lean.

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
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  3. #33
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    Quote Originally Posted by PJG1173 View Post
    I have a edelbrock 2114 vortec intake. with a mr gasket squarebore to speadbore adapter and a transdapt tbi adapter. I have an airaid CAI from the tb to the front driver fender. filter is segregated from the engine compartment by a box.
    Ok. I was thinking that maybe you were having a situation where airflow past the intake opening was generating additional vacuum in the intake tract. Similar to how carbs sticking out of a hood can have fuel issues with air flowing across the bowl vents and venturis. But your setup sounds fine. Got me stumped.

    Quote Originally Posted by EagleMark View Post
    At steady TPS 1900ish RPM 90ish MAP 60 MPH no AE or PE and WB AFR swings about 13.9 to 14.9ish? Never steady?
    I havn't looked at his log yet, but I don't think it is that uncommon for the AFR to swing that much, especially at open throttle with very little vacuum. Obviously CL will move like that, but I think even my Camaro would do that in OL. Like you said sampling whatever mixture is going by at the time and averaging them.

    I am just dumbfounded by the high map and no acceleration. I mean even in my truck, with a bone stock 120K '90 5.7 and a 9' plow on the front, my 60mph cuise is only 25%TPS, 45-50Kpa. I would think he should have as much HP and torque as I've got, in a smaller, lighter truck.
    Last edited by gregs78cam; 03-11-2012 at 07:48 PM.
    1978 Camaro Type LT, 383, Dual TBI, '7427, 4L80E
    1981 Camaro Z-28 Clone, T-Tops, 350/TH350
    1981 Camaro Berlinetta, V-6, 3spd
    1974 Chevy/GMC Truck, '90 TBI 350, '7427, TH350, NP203, 6" lift, 35s

  4. #34
    Fuel Injected! PJG1173's Avatar
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    your not the only one stumped. I know this thing wasn't ever a speed demon but I don't recall it struggling to do 60. Tonight I'm going to see if I can slow down the sampling rate of the WB and see what it does. I know in my VE table VE dosn't really climb until 2800 rpm. the high MAP readings also only happen when the TCC locks, so I might try moving the lockup point to like 75 or 80 MPH and see if that changes anything.
    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,

  5. #35
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    Quote Originally Posted by PJG1173 View Post
    the high MAP readings also only happen when the TCC locks, so I might try moving the lockup point to like 75 or 80 MPH and see if that changes anything.
    D'oh! with that 2075 RPM stall tourque converter that would give you the few hundred RPM needed to get that cam in the power band!

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
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  6. #36
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    I'm an idiot. I didn't calibrate my DRAC/VSSB for the new 36's I put on a few weeks ago. with the flip of a couple dip switches at 60 MPH im at about 30% tps and 86 kpa vise 95~100. I figured going from 35 to 36 wouldn't be a big change but the rev's per mile were way different which threw the speedo off by a large margin the faster I went.
    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,

  7. #37
    RIP EagleMark's Avatar
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    Wow? That's a good improvement! Wonder why we didn't catch that in the data log? Still think you'd do better without TCC lockup as well till say 70 MPH? Then you'd be in the RPM range of that cam!

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
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  8. #38
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    there would be no way to see that in the datalog since it refects what the vss is telling it. I think I'm still going to bump lock up higher in 4th. I don't have 4th comming in until 50 so when i get lockup in 3rd at 45 it cruises nicely.
    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,

  9. #39
    RIP EagleMark's Avatar
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    I'd definatly play with those settings. With that cam and stall tourque converter I'd think no lock up at all in third and only at 70 mph in OD would be good? Keep that motor up there in RPM range of cam to be responsive. Face it, it's not a MPG vehicle. TCC was for MPG. In your case use it as a fifth gear.

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
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  10. #40
    Fuel Injected! gregs78cam's Avatar
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    30% sounds much more reasonable, with a V6 the 86Kpa also makes sense. Cool glad ya got it.
    1978 Camaro Type LT, 383, Dual TBI, '7427, 4L80E
    1981 Camaro Z-28 Clone, T-Tops, 350/TH350
    1981 Camaro Berlinetta, V-6, 3spd
    1974 Chevy/GMC Truck, '90 TBI 350, '7427, TH350, NP203, 6" lift, 35s

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