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Thread: inj duty cycle

  1. #1
    Tuner in Training
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    inj duty cycle

    Seems like fueling problems never stop lol. The power curve feels super weird when driving and AFRs on my aem wideband go all over the place at wot and while diagnosing i realized my injector duty cycle has very aggressive dips and spikes, i know this isnt right. everything else ive tuned seems to have a smooth duty cycle that varies with rpm. This one definitely doesnt do that. Do you guys think its a tuning issue or mechanical? Injectors, wiring etc.. its a 3800 swap t5 manual trans first gen s10 with no power adding mods. New plug wires and plugs, injectors have 120k miles, have tried 3 different fuel pressure regulators, aem fuel pump. Thanks in advance! Data log and tune file will be attached s10 run 2 new stuff.hpls10 looking FAST 31.hpt

  2. #2
    Tuning Addict 5FDP's Avatar
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    Two major problems in that log, if they are true.

    Your coolant temps says it's -38 degrees and your intake air temp says it's -38 degrees. That is something you must fix. Those two issues could for sure be doing weird crap to the fueling. The MAP sensor is also stuck at 10kpa.

    I think you should re-poll for supported parameters to make sure those channels are working.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  3. #3
    Tuner in Training
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    Quote Originally Posted by 5FDP View Post
    Two major problems in that log, if they are true.

    Your coolant temps says it's -38 degrees and your intake air temp says it's -38 degrees. That is something you must fix. Those two issues could for sure be doing weird crap to the fueling. The MAP sensor is also stuck at 10kpa.

    I think you should re-poll for supported parameters to make sure those channels are working.
    I dont have either of those sensors on the vehicle and never have, because of that the tables related to temperature that adjust fueling and timing are zeroed out. And for the map sensor i have never been able to get it to read correctly even re did the wiring all the way to the ecu and new sensor but for some reason it just jacks up the way it runs and reads all funky, goes maxed out then to 50 kpa then drops to 0,etc. so ive had it unplugged for a while

  4. #4
    Advanced Tuner ZeroBoostBuick's Avatar
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    Your tune needs a little cleaning.

    Engine / Fuel / Cutoff DFCO / You have the fuel cut off RPM Limits (table 12050) is set to 5,500 rpm which is way to low. Set them to 6,500 so you never reach it. Last thing you want is the fuel getting cut off when you need it the most.


    Fuel / Transient / Acceleration... set the Throttle Based Filtered TPS (table 240) to Enabled.

    Under Spark / Retard / Maximum Knock Retard (table 12782) vs AFR,.. you have it at 5 degrees. Set it back to 11 to be safe in case you ever get bad gasoline.

    Fuel / Oxygen Sensors / feedback / exhaust config (table 212), change it to Y pipe.
    Last edited by ZeroBoostBuick; 06-05-2020 at 01:10 AM.