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Thread: 408 stroker build - need tuning help

  1. #1

    Default 408 stroker build - need tuning help

    Hey, i havent been on this page since back in 2006 or so i dont think when i had my first RT and wanted to see if you guys could help. totaled my first 99 RT RC and finally found its exact replacement(99 RT RC). i pulled the motor which has 108k miles and bought a bunch of shit from Hughes in the pics below.new everything, heads, rockers, springs, cam, crank, pistons, injectors... long story short its now a 408 stroker and sounds great and seems to be drive-able. i can add all the specs later as needed.

    for now the problem im having is finding a way to successfully tune it. Its running as of yesterday and i had 30lb injectors on it which just kept fouling the plugs. i have an SCT tuner that was programmed from Hughes to flash the PCM and account for the 30lb injectors and whatnot, but it doesnt work. it just sits on a reprogramming PCM screen and doesn't move forward after a few hours. with the 309 lb injectors the only codes its throwing is rich in bank 1 and 2, so i went back to the stock injectors and was able to drive it all day for the first time today. however it still is throwing a code for rich is bank one. im driving it very cautiously and have changed the plugs and whatnot, but dont understand why it would still be running rich with stock PCM and stock injectors on the 408 motor, it should be lean. either way all the local shops basically wont touch it. i can provide more info as is needed but i only know enought o get me into trouble and wanted to see what steps you all suggest i should take here to get her running right.
    pics below?
    thanks
    IMG_0290.jpg3C09A471-95EA-48D9-840A-7B082EF60812.jpg165BFFB7-96AC-433F-AAA9-73CE09038271.jpg18694993-AEB0-4494-91F1-EBB9F1EE5F71.jpgIMG_0293.jpgIMG_0301.jpgIMG_0300.jpgIMG_0307.jpgIMG_0320.jpgIMG_0389.jpg

    ^the old RT.. may she rest in peace

    1999 RC R/T black - 408 stroker finally running as of 11-1-18
    2004 350z black w/ nismo package
    2015 ducati panigale 899 - stock for now

  2. #2

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    Did you replace your o2 sensors?

  3. #3

    98Dak408's Avatar
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    i have an SCT tuner that was programmed from Hughes to flash the PCM and account for the 30lb injectors and whatnot, but it doesnt work. it just sits on a reprogramming PCM screen and doesn't move forward after a few hours.
    It sounds like the tune is not loading. Call Hughes and they will probably put you in contact with Chris at PIE in order to figure out why the tune is not loading.

  4. #4

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    Quote Originally Posted by moneypit View Post
    Did you replace your o2 sensors?
    they were replaceed with 02 simulators back when i had the cats cut off a long time prior to the build. never threw a code before.

    ^the old RT.. may she rest in peace

    1999 RC R/T black - 408 stroker finally running as of 11-1-18
    2004 350z black w/ nismo package
    2015 ducati panigale 899 - stock for now

  5. #5

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    Quote Originally Posted by 98Dak408 View Post
    It sounds like the tune is not loading. Call Hughes and they will probably put you in contact with Chris at PIE in order to figure out why the tune is not loading.
    i'm going to continue taking that route monday, but i was on the phone with SCT for over an hour going through steps, plugging the programmer to my laptop, letting them download things etc via remote control to my computer, and they weren't able to fix it. i called them as soon as i got the motor in though and the timing was still off. the end result of that call was to get the timing fixed so it would idle then try again. my cam position sensor was being rubbed by the flywheel becuase it was bent, so it was throwing cam sensor codes at the time. (all that is fixed now)... either way i have tried several times to let the program run since then and it just sits on the unlocking PCM screen. it reads codes, erases codes and reads truck info fine, just wont program it. the SCT guy mentioned on the phone that this particular year was difficult to tune due to the age of the computer or something.. im not sure how true this statement is, but the local shops all tell me the same thing. cant tune these trucks very easily until the 2003 models.

    ^the old RT.. may she rest in peace

    1999 RC R/T black - 408 stroker finally running as of 11-1-18
    2004 350z black w/ nismo package
    2015 ducati panigale 899 - stock for now

  6. #6
    niebs's Avatar
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    Quote Originally Posted by DakRT360 View Post
    they were replaceed with 02 simulators back when i had the cats cut off a long time prior to the build. never threw a code before.
    Which ones did you remove? Do you have a wideband installed for tuning? or any o2 sensors?

  7. #7

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    Quote Originally Posted by niebs View Post
    Which ones did you remove? Do you have a wideband installed for tuning? or any o2 sensors?
    i got my trucks mixed up. this one still has all the factory o2 sensors. i havent bought a wideband yet, was told this custom tune on the SCT programmer wiould be all i needed initially, so ill prob go that route if i cant get it to flash.

    still though, why would one bank be rich with the stock injectors. seems like they wouldn't be able to deliver enough fuel to run rich even in just one bank.

    ^the old RT.. may she rest in peace

    1999 RC R/T black - 408 stroker finally running as of 11-1-18
    2004 350z black w/ nismo package
    2015 ducati panigale 899 - stock for now

  8. #8

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    are there not tons of people that have built their trucks into the 408? i assumed there was a pretty solid process for flashing our computers by now?

    ^the old RT.. may she rest in peace

    1999 RC R/T black - 408 stroker finally running as of 11-1-18
    2004 350z black w/ nismo package
    2015 ducati panigale 899 - stock for now

  9. #9
    niebs's Avatar
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    Quote Originally Posted by DakRT360 View Post
    still though, why would one bank be rich with the stock injectors. seems like they wouldn't be able to deliver enough fuel to run rich even in just one bank.
    well its rich with both set of injectors in it. So it sounds like something is telling the injectors to hang open (tune).

    So figuring out the sct issue would be the first thing to sort out.
    and i wouldnt drive it until it is sorted out.

  10. #10

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    got ya, thanks.
    any experience with sorting out the SCT tuner? even the SCT tuner guy said this computer was difficult to flash

    ^the old RT.. may she rest in peace

    1999 RC R/T black - 408 stroker finally running as of 11-1-18
    2004 350z black w/ nismo package
    2015 ducati panigale 899 - stock for now

  11. #11



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    Ugh..
    This brings back old memories. Bad memories.
    Good luck. I gave up.
    11.27 @ 118.23
    2017 NM Mopar Challenge Series Champion

  12. #12

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    Quote Originally Posted by Adobedude View Post
    Ugh..
    This brings back old memories. Bad memories.
    Good luck. I gave up.
    this is not welcome news good sir. what'd you do to yours to get past these issues?
    thanks

    ^the old RT.. may she rest in peace

    1999 RC R/T black - 408 stroker finally running as of 11-1-18
    2004 350z black w/ nismo package
    2015 ducati panigale 899 - stock for now

  13. #13

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    here is the invoice of shit im running with btw. still sounds like all i need is a tuner that actually works.... should i be posting this somewhere else to get more feedback? seems like this website got a lot more attention back when i had my first RT. any help is extremely appreciated. i know nothing of how these PCMs work and it sounds like thats the biggesst problem.dak list 1.jpgdak list 2.jpg

    ^the old RT.. may she rest in peace

    1999 RC R/T black - 408 stroker finally running as of 11-1-18
    2004 350z black w/ nismo package
    2015 ducati panigale 899 - stock for now

  14. #14

    98Dak408's Avatar
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    I don't know what size cam you have but if the tune is not loading it is going to run rich. (Your list of mods is too small to read.) You need to sort that out before throwing money at other things in my opinion..

  15. #15


    krs1r/t's Avatar
    want more inchs STROKE IT

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    Chris at performance injection equipment will get you straightened out

    Bad Luck Truck
    Current setup
    „R„block 429ci W5 heads 700hp N/A
    1/8 mile #'s 6.47@105 1.37 60’ 10.23@131

    Old 1/4 numbers below with 408
    Fastest N/A 2010,2011,2014
    477-RWHP ?-RWTQ

    11.244 ET @ 119.71mph N/A
    FOXHOLE RACING
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  16. #16

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    Quote Originally Posted by DakRT360 View Post
    this is not welcome news good sir. what'd you do to yours to get past these issues?
    thanks
    He went carburetor, coil and distributor. Ripped out all the computer crap in between.

  17. #17


    krs1r/t's Avatar
    want more inchs STROKE IT

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    Don't run it and wash the cylinder walls with fuel, if you havnt already.

    Bad Luck Truck
    Current setup
    „R„block 429ci W5 heads 700hp N/A
    1/8 mile #'s 6.47@105 1.37 60’ 10.23@131

    Old 1/4 numbers below with 408
    Fastest N/A 2010,2011,2014
    477-RWHP ?-RWTQ

    11.244 ET @ 119.71mph N/A
    FOXHOLE RACING
    "If you like me good, if you hate me, even better!"
    Chris

  18. #18

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    Ill call SCT again tomorrow and ask for chris. maybe we can get it programmed this time. last time we even made a test tune and tried to program it as well and it didint work either. again, its reading codes and everything else seems to be working fine, just wont take the tune...
    thanks for all your help

    Attachment 15205

    ^the old RT.. may she rest in peace

    1999 RC R/T black - 408 stroker finally running as of 11-1-18
    2004 350z black w/ nismo package
    2015 ducati panigale 899 - stock for now

  19. #19

    98Dak408's Avatar
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    There may be a Chris at SCT tune but you won't find Chris from PIE (who apparently did your tuning) there. You'll either have to contact Hughes Engines or call Chris directly in Delaware. Or, maybe SCT can try again to get it to work.

  20. #20
    nitroram33's Avatar
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    I know that when Ryan did my tune he asked for the model number of the PCM so he could do the SCT tune correctly as there are differences in setup between different PCM part numbers and revisions, maybe whenever the tune was done they based it around the wrong part number?

  21. #21

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    Quote Originally Posted by 98Dak408 View Post
    There may be a Chris at SCT tune but you won't find Chris from PIE (who apparently did your tuning) there. You'll either have to contact Hughes Engines or call Chris directly in Delaware. Or, maybe SCT can try again to get it to work.
    do you have his contact info? i only went through SCT before, haven't spoke to chris.
    ill call hughes again tomorrow to try to get it

    ^the old RT.. may she rest in peace

    1999 RC R/T black - 408 stroker finally running as of 11-1-18
    2004 350z black w/ nismo package
    2015 ducati panigale 899 - stock for now

  22. #22
    Any R/T's's Avatar
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    Look in Supporting Vendors on this Form or www.performanceinjectionequipment.com

  23. #23

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    thanks again for the help on this. the outcome was that if you follow the prompt on the SCT tuner, then youll never be able to program our trucks because it tells you to leave the key on when it needs to be off, and take the key out when it needs to be in the run position.... anyway i finally got it tuned and its still running rich. so i have a wideband on order from Pie and sent all my info over to chris so he can help me tune it once the wideband is installed.

    my truck currently has headers to 3" true duals with no CATs. it has a sensor in the drivers side exhause just after the header coupler and one in the passenger side just before what would be the CAT if i still had them. then a third on the passenger side post CAT. my understanding is the third post cat sensor doesn't actually change anything on the computer and is just for emissions. since its basically useless shoud i just plug the wideband in there or would that be too far from the headers? and if i need to add another bung should i go passenger side or driver?
    thanks

    ^the old RT.. may she rest in peace

    1999 RC R/T black - 408 stroker finally running as of 11-1-18
    2004 350z black w/ nismo package
    2015 ducati panigale 899 - stock for now

  24. #24
    blackknight's Avatar
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    I have mine about a foot, foot and a half behind the collector on the passenger side

  25. #25

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    So ive welded in the bung and have my wideband wiring started but i can't find a decent location to tap the power wire in. anyone have a suggestion for an easy to access switched wire under the dash? instructions say not to use any wires running from radio, ecu, ignition etc... or i can probably run it to an empty spot on the fuser box but that seems lkiuke more work than is necessary. i purchased the innovate MTX-L plus

    ^the old RT.. may she rest in peace

    1999 RC R/T black - 408 stroker finally running as of 11-1-18
    2004 350z black w/ nismo package
    2015 ducati panigale 899 - stock for now

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