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Boosted 5.3 misfire in boost

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Old Sep 27, 2013 | 06:05 PM
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Default Boosted 5.3 misfire in boost

It honestly feels like I am hitting a rev limiter. It is a little fat, but not overly so. But when going into load/boost it stumbles badly and misfires. It sometimes will pull through and clean up, but not sure why it is happening. I just changed out the plug wires to try to eliminate that. Next comes the plugs. Here is the scan and tune. It is a work in progress and my first boost ls motor, so be gentle Let me know if you see anything out of the ordinary.
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File Type: hpl
cruise and stumble 9.27.13.hpl (111.8 KB, 119 views)
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Old Sep 27, 2013 | 06:16 PM
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Car is also running on E85 as a fyi.
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Old Sep 27, 2013 | 06:20 PM
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More info...
5.3
227/233 cam
hi ram intake
4l80E trans from Jakes
S480 turbo
160 lb injectors (hi-z)
plenty of fuel pump
55 psi base pressure
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Old Sep 28, 2013 | 12:10 PM
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Plugs were ok. Going to try adding some grounds and running a better wire from alternator to the battery. For questions I got on hptuners, I never went wot as it was breaking up so bad. I was trying to roll into it. Also the injectors are scaled in half to add more resolution to the tune.
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Old Sep 28, 2013 | 01:27 PM
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Added a ground and made the old ground better and cleaned them all off. Ran a better wire for the alternator to the battery so I have better voltage. Changed the plugs and still same thing if not worse. Getting quite frustrated on this one.
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Old Sep 30, 2013 | 06:59 AM
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Does this happen at all boost levels?
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Old Sep 30, 2013 | 08:20 AM
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It was yes and actually before boost came on slightly. I did lean it out and was able to get some almost clean pulls before I scrubbed a tire on the rear fender and took a nice slice out of the rear tire.....doe! I am thinking at this point I have a mild exhaust leak (can hear it and see a little carbon) that is causing the wideband to read leaner than it actually is. When I go mid to low 11s on the gas scale it cleans up a good bit.

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Old Sep 30, 2013 | 05:06 PM
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I was just going to mention checking the wide band. Can't be spark blow out or valve float if its before boost. Also what spark plug wires?
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Old Sep 30, 2013 | 07:28 PM
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Yeah I think at this point the wideband is giving a falsely lean reading. I would not think this would happen with the backpressure in the exhaust, but I guess it is? I had a coupler blow off and was able to see how it reacted in NA form on the way home. It was hitting 10.8 in NA form right before boost would have set in, like 101 kpa. I have tried both factory wires and now Taylor wires.
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