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Thread: Plugged exhaust ? please look at log

  1. #1
    Tuner in Training
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    Plugged exhaust ? please look at log

    Recently built 5.3 swap in a 07 sierra Gen3 DBW with TSP stage 1 cam and valve springs. trying to figure out why it has absolutely no power and wont even break the tires loose. TM removed and runs the same, back to stock even worse. I noticed that my KPA readings go to 100KPA under heavy load which I dont think is normal for a NA motor. Thought maybe a cam tooth off but thats good. Now wondering about if the exhaust possibly plugged or restricted. blew the tires off it when it the 4.8 in it with the same exhaust hard to believe an extra.5 liter slowing it down. Running out of ideas any help would be very appreciated.
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  2. #2
    Advanced Tuner dhoagland's Avatar
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    One thing I notice is that your are not commanded any Power Enrichment, even at 85% throttle your commanding 14.xx. I'm not familiar with this OS, but I'm thinking the table: Engine>Fuel>Power Enrichment> Throttle> Hot select Needs changed. It is set to 285. The way I read this is the engine must be at 285 to enter PE (maybe I'm backwards). Your wideband is showing AFR 15 so you are lean. I would get this figured out first
    2011 Camaro 2SS Convertible L99 Bone Stock for now
    2003 Dodge 2500 5.9 Cummins QC 4x4. Airaid, 2nd Gen Intake, Grid Heater Delete, D-Tech 62/65/12, Magnaflow. Bully Dog: Propane Injection, Triple Dog W/Outlook Crazy Larry. Edge EZ, BD Flow-Max, 48RE: Sonnax Sure Cure/Transgo combination, Derale turbulator, billet input, Triple Disc, Super servo, 4 ring Accumulator. :beer

  3. #3
    Tuning Addict 5FDP's Avatar
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    Yep, it's going lean under heavy throttle.

    Brake torque mngt in the systems tab is still on, that could prevent you doing a burnout.
    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.

  4. #4
    Advanced Tuner TheMechanic's Avatar
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    Pull the O2 sensors and start it. You can hear the exhaust pulse will be very noticeable with a plugged exhaust. I have an exhuast pressure tester I use that screws into the existing O2 bung. Works great. Should be able to get a cheap Chinese throw away that will help

  5. #5
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    On my old 0411 DBC truck I could light the tires easily even with brake torque management on but the P59 DBW is a whole different animal I guess. I have several licensed 0411 PCMs and considering re pining it for DBC but worried it will light up my message center like a Christmas tree. loosened the muffler flange bolts and drove it around the block and it only made more noise no power. 150lbs compression cam is only 208/214 .550/.550 lift cam.

  6. #6
    Advanced Tuner dhoagland's Avatar
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    Quote Originally Posted by TheMechanic View Post
    Pull the O2 sensors and start it. You can hear the exhaust pulse will be very noticeable with a plugged exhaust. I have an exhuast pressure tester I use that screws into the existing O2 bung. Works great. Should be able to get a cheap Chinese throw away that will help
    What kind of back pressure is normal? Is it PSI or Inches of Water?
    2011 Camaro 2SS Convertible L99 Bone Stock for now
    2003 Dodge 2500 5.9 Cummins QC 4x4. Airaid, 2nd Gen Intake, Grid Heater Delete, D-Tech 62/65/12, Magnaflow. Bully Dog: Propane Injection, Triple Dog W/Outlook Crazy Larry. Edge EZ, BD Flow-Max, 48RE: Sonnax Sure Cure/Transgo combination, Derale turbulator, billet input, Triple Disc, Super servo, 4 ring Accumulator. :beer

  7. #7
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    Think I found my problem. Trying to VE log this whole time with dynamic air RPM disable set to 100 instead of 10000 RPM. Kind of hard to run right and get any accurate data that way.