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Thread: tuning 454 problems 411 ecm

  1. #1
    Advanced Tuner
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    tuning 454 problems 411 ecm

    I have a 99 1 ton chevy 454 that I removed the stock ecm over a year ago and swapped to the 411 ecm for more tunning options. Ever since the swap if I start the truck when it has been started with in a hour from shutting it off you have to give it gas once it starts to keep it running like 1200 rpm for 10-15 seconds then it is fine. Thinking that has something to do with the idle air control. But can't figure out what to change. But the bigger problem is for the last couple weeks it has not wanted to idle at all. you almost have to drive it two footed or bump to neutral for stop lights it may do it then you can drive on the highway or down the road a mile or two and then it may not do it again for the rest of the day. Then today we got snow so I started the truck to pull out of garage to start plowing my 1600 driveway and turn around and it would not stay running. So I went to parts store and replaced cap and rotor again with ac delco parts only 8 months old on old stuff. Seems like these vortec motors are notorious for caps. I put it all on this mornig and then plowed my driveway again then about 2 hours later went and plowed another drive and ran great so figured that fixed it. Pulled truck back in garage and 5 hours later just went out to push my driveway off again and ran like crap again will not stay runnig have to drive two footed. I have looked for over a year trying to find some tunes of guys that are using the 411 on their 454 and can not find any to see what I have wrong. I know it is started with a 5.7 tune from a express van and changed from there I am thinking something from the 5.7 did not get changed right for the 454. Please take a look at tune and see if you can help.
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    Last edited by badbowtie; 01-02-2014 at 06:13 PM.

  2. #2
    Advanced Tuner blownbluez06's Avatar
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    In the fuel section, the prime re-enable run time value controls when you get priming fuel. The vehicle has to sit for more than that amount of time (in seconds) before it'll get a prime shot on startup. The value you have in there is 4 hours. Try something lower.
    I don't think your OLFA table is dialed in sufficiently. It is commanding less fuel than I would command at the lower temp values. I have a hard time believing your motor likes 9 degrees timing at WOT. I also have a hard time believing that your idle spark isn't too high. When you factor in overspeed/underspeed, you give it no headroom.
    Turn off your LTIT's and log STIT's. Re work your idle airflow table. Here's a hint: it requires more air to keep a vehicle idling when in gear. Dial it in from a cold startup with the AFR's properly set, in park and then do it in gear. I like to always keep STIT's slightly negative. Make sure your TPS is at 0 if this is a DBC setup and don't worry about it if it's a DBW throttle body arrangement.
    Make sure the PCM knows whether its in gear or not.
    Hsquared racing engines RHS 427, Procharger F2, Moran Billet Atomizer injectors, Alky Control,Mast LS7 heads, Nitrous outlet kit,Tilton quad disc clutch, DSS shaft, RKT56 ZR1 trans, RPM Quaife diff. Built and tuned by yours truly.

  3. #3
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    Thanks I will look into the prime re-enable. That makes sense just not sure what to lower it to. I will also start checking tables again and try to get this thing dialed in closer and see what happens I thought 9 was to low on timing but when I get on it I keep picking up knock but assume it is false knock. I also not sure if due to ecm is based of the 5.7 not the 454 so not sure if knock sensor settings are the issue but can't figure out what to chang. I will have to re read the how to on redoing the airflow table first if I can find were I read it.

  4. #4
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    If your having problems with the caps if I'm not mistaken you could convert to the LS coils and use the distributor for you signal.

  5. #5
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    Yea I really have thought about switching that and doing coil on plugs I just have some reading to figure it all out.

  6. #6
    Potential Tuner littleK5's Avatar
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    Dec 2012
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    97 4544l80e 411 swap file

    This tune still needs work but it runs well and gets about 15 highway.
    97 2500hd Long tube headers, 3in duals with H pipe LS6 injectors, 35s
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  7. #7
    Tuner in Training
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    Nov 2014
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    1997 C3500 crew cab dually here
    long tube headers, true duals, deleted cats and rear o2's, lookikng to upgrade to ls6 injectors, a single plane intake with elbow, harland sharp roller rockers with conversion studs, a bigger TB (1200cfm), adjustable fuel pressure regulator and bigger rails.. one day a cam


    littleK5 i am gonna use your tune to start

    any updates?