LS2 Engine in race truck...

Discussion in 'Shop - Engine' started by Biokiller, Mar 31, 2012.

  1. Biokiller

    Biokiller Member

    Joined:
    Sep 18, 2011
    Location:
    Chicago
    Hey guys. Don't know if anyone is running any LS based motors in there trucks?? We have a LS2 in ours and are using the stock computers that are tuned to run it. In the Mint 400 we had all kinds of computer issues. I did place them under the hood, so we where thinking that the heat was a huge factor???
    What are you guys running for computers??? MEFI4??

    We like the tuning of the stock computers, just don't know if they can handle the beating in the desert.

    Thanks for any imput and help.
    Tom
  2. redline

    redline Active Member

    Joined:
    Oct 1, 2001
    Location:
    Palm Springs
    There are plenty of people running mefi computers in the desert. Usually its wiring and not the computer itself that has the issue. Heat could possibly have effect though too. What were the issues you had? Chris at Danzio can set you up with a really nice Life ecu for a decent price though! A lot more tuneable and resourceful than mefi.
  3. FlyHiFlyLo

    FlyHiFlyLo Ace Mechanic

    Joined:
    Dec 9, 2003
    Location:
    North Mexico
    What are you doing in the truck when it starts tweaking out on you?
  4. Biokiller

    Biokiller Member

    Joined:
    Sep 18, 2011
    Location:
    Chicago
    What would happen is I would loose 4th gear then 3rd. after a little while, the truck would just shut off. also had some bad backfiring @ wide open throttle. We would let it site for about 5 minutes, then all would be fine till it got hot again which was about 10 minutes later!!

    My oil and water temps where fine, I just think its the heat from the headers??? I had no issues in testing, but I wasn't pushing it as hard as we did in the race.
    I will look up Danzio and see what they can do for me. I hate to have to buy a whole new harness!!

    Thanks for the help guys.
  5. FlyHiFlyLo

    FlyHiFlyLo Ace Mechanic

    Joined:
    Dec 9, 2003
    Location:
    North Mexico
    It could be the trans PC board wigging out. Is it a 4L60?
  6. FlyHiFlyLo

    FlyHiFlyLo Ace Mechanic

    Joined:
    Dec 9, 2003
    Location:
    North Mexico
    Also, what err codes are you getting when it loses 3/4.
  7. Biokiller

    Biokiller Member

    Joined:
    Sep 18, 2011
    Location:
    Chicago
    4l80e trans. No check engine light @ all!!! Was not able to put the scanner on it. Might check tomorrow to see if there is any stored codes. Has me baffled!!! But thats not hard when it come to computers!!
    Thnaks for the help.
  8. cncman

    cncman Member

    Joined:
    Dec 5, 2007
    Location:
    Gardena ca
    Sound like you had a fuel delivery issue, not a computer issue.
  9. drivehard

    drivehard Member

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    Oct 1, 2007
    Location:
    so cal, CA
    Fuel, maybe for the backfire. Doubtful with the other stuff going on. Is there a reason you guys put the computer with engine and not in the cab?
  10. Biokiller

    Biokiller Member

    Joined:
    Sep 18, 2011
    Location:
    Chicago
    Lack of experience!!!
    Spoke with a few people on this and they siad the computer "could" take the heat!!!
    I doubt it is fuel issues. I think once the computers heated up, it would just freak out the programming and screw it all up.


  11. FlyHiFlyLo

    FlyHiFlyLo Ace Mechanic

    Joined:
    Dec 9, 2003
    Location:
    North Mexico
    Just like the 4L60 the 80 can put the ECM in limp mode too... Use a darn scanner. Seems the 3/4 soleniod wasn't diverting pressure from the valve body... 100% computer controlled stuff there. On the 4L80, high trans temps will do this. If you are running a 4L80 like you are you NEED a compushift computer. This will provide you with tons of trans diagnostics. And it will also help you correctly set the TCV. The compushift computer is awesome and even lets you set shift points and throttle pressures for every gear. The computer under the hood is no big deal so long as it is totally protected from moisture.

    Take two computer scans and call back in the morning.
  12. FlyHiFlyLo

    FlyHiFlyLo Ace Mechanic

    Joined:
    Dec 9, 2003
    Location:
    North Mexico
  13. GAME OVER?

    GAME OVER? Almost There

    Joined:
    Nov 16, 2006
    Location:
    San Marcos CA
    Can you duplicate the problem pretty easily or is it intermittent? If its a re-accuring proble call Chris at Danzio and toss it on his dyno. Should be able to figure it out real quick. I would imagine those ECUs can take some pretty good temps.
  14. FlyHiFlyLo

    FlyHiFlyLo Ace Mechanic

    Joined:
    Dec 9, 2003
    Location:
    North Mexico
    From his avitar looks like he is in Chicago.
  15. Biokiller

    Biokiller Member

    Joined:
    Sep 18, 2011
    Location:
    Chicago
    Yes I'm in Chicago. Not easy racing out west living in this **[​IMG] ¡Ay, caramba!****[​IMG] ¡Ay, caramba!****[​IMG] ¡Ay, caramba!****[​IMG] ¡Ay, caramba!** hole!!!

    The only time I had this issue was in the race. Testing was fine, but we didn't push the truck as hard.
    Trans temps where 160 max. I have fixed the cooling issues I HAd with the trans, not runs real cool.
  16. rickf

    rickf Active Member

    Joined:
    Oct 27, 2007
    Location:
    Temecula, Ca
    (kind of a sidetrack)
    Where are you taking the trans temp?
    The best way is in the pan AND outgoing to the cooler, lets you know what's really going on with the tc.
    Insufficient flow can give you low pan temps while you burn down the tc.
  17. FlyHiFlyLo

    FlyHiFlyLo Ace Mechanic

    Joined:
    Dec 9, 2003
    Location:
    North Mexico
    The 4L80 has the trans temp sensor in the VB........ Compushift... This really seems like a trans issue and not an engine issue.
  18. cncman

    cncman Member

    Joined:
    Dec 5, 2007
    Location:
    Gardena ca
    That computer will take more heat than most of the RACING computers out on the market
    Delphi spends millions to make sure of simple things like heat, vibration, water.
    Last edited: Apr 1, 2012
  19. Biokiller

    Biokiller Member

    Joined:
    Sep 18, 2011
    Location:
    Chicago
    I have the trans temp in the pan.



  20. Biokiller

    Biokiller Member

    Joined:
    Sep 18, 2011
    Location:
    Chicago
    That is what I thought. Almost all factory computers are under the hood. Maybe I just have a bad computer??

    If it was just the trans, why would the motor be acting up and then just shut off??

    Why did I have to try something different!!! Nothing but problems from day 1!!!


    Thanks for all the input guys.


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