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Thread: 2006 5.7 Vortec PO300 troubleshooting.

  1. #1
    Lifetime Member
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    Default 2006 5.7 Vortec PO300 troubleshooting.

    I have a 2006 Chevy 3500 van with the Vortec 5700 that died. The place they towed it to replaced coils, plugs, MAF and O2 sensors. Now it starts immediately, has a P0300, and shakes/runs horrible from idle through upper RPM. Coolant and oil levels were normal. In/out of gear made no difference.

    Is someone able to page through this log file to see if there is anything obvious that was missed? It will be quite a road trip for me to go look at.
    Attached Files Attached Files
    2003 Chevy S10 4.3L LU3 LS1B Auto
    48 LB injectors
    Race Proven Motors 2114 intake
    T70 turbo.

  2. #2
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    Hiya,
    I can't remember if the vans still had a distributor or if they were coil near plug.
    If distributor/wires they have the firing order wrong(probably old sbc), the new stuff is LS1 firing order.

    Ignition Firing Order For Misfire Detection

    Sequence Cylinder #
    7th 4
    8th 3
    1st 1
    2nd 8
    3rd 7
    4th 2
    5th 6
    6th 5

    Well shoot, I just looked up a 2003 Express van 5.7L and it still uses the standard firing order(18436572) vs the LS1 firing order(18726543). Either way, if it is using the "crab cap" cam sensor distributor, it's very easy to have wires mixed up, you have to pay close attention to the terminal vs wire and not just location like the old days.
    Last edited by In-Tech; 1 Week Ago at 12:37 PM.

  3. #3
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    Coil near plug (No distributor). It's basically an LS motor with a cast iron block.
    2003 Chevy S10 4.3L LU3 LS1B Auto
    48 LB injectors
    Race Proven Motors 2114 intake
    T70 turbo.

  4. #4
    Senior Member
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    Dec 2016
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    Default

    If you get a chance, post a pic of those valve covers with the coils. I'm curious how they look.

  5. #5
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    Ok so it's either a 5.3 or 6.0 if it's LS based in a van, the only 5.7s in vans were a SBC and stopped after 2002/2003ish (in the US/Canada, other markets like Mexico had the SBC for a few more years).

    I looked at the log, it ends right as the van gets near normal operating temp. The idle spark is jumping around a decent amount and STFTs are negative, but both STFTs and O2 mV swings look semi normal.

    How did it die originally? Has a compression and/or leakdown test been done? Wondering if there's physical damage.
    ~Erik~
    2013 Sonic RS Manual - 1.4L I4T E78, tuned, turbo mods, etc.
    2008 TrailBlazer SS 3SS AWD Summit White - LS2 E67/T42, bolt ons, suspension, etc.
    2002 Chevy TrailBlazer LT 4X4 Summit White - 4.2L I6 P10, lifted, wheels, etc.

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