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Thread: SBC TPI 0411 24X conversioin

  1. #31
    Fuel Injected! Mikey G's Avatar
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    Quote Originally Posted by evilstuie View Post
    Well I've still got some misfiring issues I think. Going to hit the exhaust ports today with a laser thermometer and see if I can find a cylinder that's not firing.
    I also bit the bullet and bought the HP tuners suite and scantool to help diagnose and tune. I installed a fuel pressure gauge, wideband and vacuum gauge, and can now see i've got between 7-11" of vacuum that bounces around wildly, and with the XR270HR cam in a 400SBC, it should be more around the 15-20" and very steady, so I have to go exploring after the misfiring is fixed to see what's causing it.

    My next best guess is either a vacuum leak on the intake gasket, or something more sinister like a cam lobe being wiped, collapsed/spun lifter, valve seal or something else mechanical.
    From what I've read there's also the possibility the low vacuum is because the valve timing is wrong. I've checked for vacuum leaks outside the motor, so maybe it is in the motor.
    Looking to see if you're firing on all cylinders with a temp gun is very useful - correct if required
    Check your initial and total timing. Engine can sound quite good but have a low vacuum.
    How are you checking for vacuum leaks? What intake you using? - Perhaps a missed open port somewhere? (I've been fooled at least half dozen times )

    Let me know,

    Mikey G

  2. #32
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    Check the injectors are wired correct you have to shift them to the right cylinders to match the firing order it can't be changed in the tune have to physically shift them or they run a little off and do funny stuff.if you just dropped an ls harness on as it was some will be wrong

  3. #33
    Fuel Injected! Mikey G's Avatar
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    See attached schematic I found on the internet and used in my build.
    Attached Files Attached Files

  4. #34
    Fuel Injected! Mikey G's Avatar
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    There are injectors and coil connections to swap out when going from LS to SBC
    I have build three stand alone harnesses for others with no issues
    Let me know

    Mikey G

  5. #35
    Fuel Injected! Mikey G's Avatar
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    Need to swap out injectors 2&3 and 4&7
    also need to swap injectors 2&3 and 4&7
    That being said, motor will not fire up if this was not done. I'm sure this is not your issue for the erratic vacuum.
    Mikey G

  6. #36
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    And have to change bank assignments in tune so the O2s read the correct cylinders for missfire detection etc hard for the ecu to swing o2s if the banks are messed up

  7. #37
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    Quote Originally Posted by delcowizzid View Post
    And have to change bank assignments in tune so the O2s read the correct cylinders for missfire detection etc hard for the ecu to swing o2s if the banks are messed up
    Hey guys,

    Thanks for the tips, it's appreciated.

    I've been through the harness about 4 times now and checked every single pin from PCM to the other end to make sure it's all correct. I found the issue with the vortec dizzy pins being different to the Cam position sensor in LS motors and fixed that also, so I know all the wiring is correct.

    Bank assignments have been set correctly in the tune as well.

    As you mentioned about vacuum lines, I also found one of the pipes on the throttle body that i think is usually a heater hose line was actually a vacuum hole, so I plugged that and fixed that.
    I've used carby cleaner to check for vacuum leaks around the front and back of the block where the intake sites, as well as the sides and the plenum (sorry, forgot to mention its a Holley Stealth Ram intake).

    Basically the car runs rough at idle which i still think is a fouled plug, then when it warms up its ok - All this is at idle.
    When driving, the car will go when I open the throttle, but when the transmission shifts, the car bogs right down, backfires, and bucks like crazy, for almost exactly 3 seconds, then I can put the foot down again and get going, but only at cruise throttle.

    The motor is a 400SBC, stock bottom end, stock pistons, but XR270HR cam, AFR 195 eliminator heads, heavily ported to around 220cc, and 64/68cc chambers, can't remember at the moment.
    The holley stealth ram intake has an arizona marine 58mm twin throttle body, 28lb/hr ls1 injectors, with the vortec dizzy and timing cover to give the 0411PCM the signals it needs.
    Running MAFless tune with 12202088 type OS, custom 0129003

    Once HP tuners arrives I can use their RTT OS and set the timing to a specific value to see if the rough idle gets better or if vacuum improves from there, as well as recheck the A/F Ratio to see if that's what's sooting up the plugs

  8. #38
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    Is it the non adjustable dizzy that doesn't turn to adjust my mates bigblock was 1 tooth out on the rotor phasing and it did similar he also had the injectors out of order

  9. #39
    Super Moderator dave w's Avatar
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    The SBC firing order is 1-8-4-3-6-5-7-2.

    The 5.3 liter (LSx) firing order is 1-8-7-2-6-5-4-3.

    It's my understanding changing the '0411 bank assignments in the flash, DOES NOT change firing order. The '0411 24x firing order can be changed by re-pinning the Injector and Coil Pack wiring.

    dave w
    Last edited by dave w; 01-20-2018 at 05:40 PM.

  10. #40
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    Quote Originally Posted by dave w View Post
    The SBC firing order is 1-8-4-3-6-5-7-2.

    The 5.3 liter (LSx) firing order is 1-8-7-2-6-5-4-3.

    It's my understanding changing the '0411 bank assignments in the flash, DOES NOT change firing order. The '0411 24x firing order can be changed by re-pinning the Injector and Coil Pack wiring.

    dave w
    BOTH need to be done. Injector bank assignment and diagnostic firing order need to be changed in the tune and both the injectors and coils need to be re-pinned at the PCM. Easy way to correct those is copy in the table values from a 5.7 Express van tune. I am running my 5.7 on a modified 6.0L tune in a 1 meg PCM (Green/Blue connectors).

  11. #41
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    Quote Originally Posted by Fast355 View Post
    BOTH need to be done. Injector bank assignment and diagnostic firing order need to be changed in the tune and both the injectors and coils need to be re-pinned at the PCM. Easy way to correct those is copy in the table values from a 5.7 Express van tune. I am running my 5.7 on a modified 6.0L tune in a 1 meg PCM (Green/Blue connectors).
    Yeah both have been done.
    Repinned the coils and injectors on the harness and reassigned the injector banks on the tune. The injector bank assignment is just for the o2 sensors, there's no way to change the firing order in the tune.

    The dizzy could be out by a tooth or 2, but it should come up as a DTC if it's out of sync I think.

  12. #42
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    Quote Originally Posted by evilstuie View Post
    Yeah both have been done.
    Repinned the coils and injectors on the harness and reassigned the injector banks on the tune. The injector bank assignment is just for the o2 sensors, there's no way to change the firing order in the tune.

    The dizzy could be out by a tooth or 2, but it should come up as a DTC if it's out of sync I think.
    You are WRONG on the being able to change the firing order in the tune. It is there plain as day in both HP Tuners and TunerCats OBDII. It is in the diagnostic tab and tells the PCM in what order the cylinders fire for misfire monitoring and cylinder specific DTCs.

  13. #43
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    Quote Originally Posted by Fast355 View Post
    You are WRONG on the being able to change the firing order in the tune. It is there plain as day in both HP Tuners and TunerCats OBDII. It is in the diagnostic tab and tells the PCM in what order the cylinders fire for misfire monitoring and cylinder specific DTCs.
    Oh ok. I've been using EFI Live and TunerPro up to this point and they never had anything to change the firing order. As I said HP tuners is still on its way to me so I haven't had a play around yet.

    Regardless I did it the long way and repinned everything.

    Is it possible the PCM needs the CASE relearn procedure. From what I remember reading it is supposed to sync the cam and crank sensors yes? But only works if they're already within 2degrees?

  14. #44
    Super Moderator dave w's Avatar
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    My apologies, I thought the topic was SBC 24x '0411. It appears the thread has wondered to the SBC 4x '0411?

    I have experience with the SBC 4x '0411 conversion. I use the FACTORY 2002 Express Van L31 SBC 4x '0411 wiring diagrams, FACTORY L31 Cam / Crank sensors and the FACTORY Ignition Coil / Module on the systems I've worked with. It's a good parts combination / foundation to use for the SBC 4x '0411 conversion. The SBC 4x "0411 initial cam / crank alignment MUST BE 100% "SPOT ON", or "HEADACHES" will result. I use the 2002 Express Van Flash, OS 12212156 with the SBC 4x '0411 conversion.

    My daily driver is a 1999 S10 / upgraded with a Stock L31 / using the EFI Connection 24x crank trigger system. I'm using the FACTORY 2002 LM7 wiring diagram, modified for the SBC 24x system. I often use my daily driver to "Test" an '0411 PCM. When testing an '0411, I use the same flash the daily driver '0411 has with the CASE disabled in the "Test" flash. I haven't noticed any drive-ability issues with the CASE disabled flash. I'm using a "EXTENSIVELY" modified Drive by Cable LM7 5.3 liter OS 12212156 Flash for my SBC 24x conversion.

    dave w

  15. #45
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    Quote Originally Posted by Fast355 View Post
    You are WRONG on the being able to change the firing order in the tune. It is there plain as day in both HP Tuners and TunerCats OBDII. It is in the diagnostic tab and tells the PCM in what order the cylinders fire for misfire monitoring and cylinder specific DTCs.
    Hey Fast355,
    I just downloaded the VCM editor for HP Tuners and found it as you said on the diag tab. Wow, this could be an issue if both have been done then essentially it's just cancelled the change out.
    But the TunerPro XDF I was using didn't have an option for firing order, so I assume the firing order is still set to LS1 and repinning has corrected the firing order.

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