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Thread: LS3 DTC MAF/Throttle Problem (all new and untuned)

  1. #1
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    LS3 DTC MAF/Throttle Problem (all new and untuned)

    Hi to all.

    My name is Raul, i live in Spain, so there are not many LS engines here. One of my customers has done a LS3 swap in a Nissan 350z, so we went to all new Crate engine with stock wiring and stock E38 ecu, all ready for swap.

    We installed all, the car starts but we have a problem with the Throttle, if we pushed the gas pedal to the floor and got the rev limit, a DTC appears, sometimes soon, sometimes later. The throttle does not work and lambda sensors don't adjust. The DTC are
    P0068 MAP/MAF. Throttle position correlation
    P0102 Mass or Volumen Air Flow A Circuit Low

    we checked the wiring (new and ready for swap), connectors, and throttle blade (swapped for other), checked the correct MAF direction and position. The Maf gets us 20 g/s at 1000 idle revs. Our intake is a Sikky 4" tube and the Ecu is a E38 with a "stock" map (came from turnkeyengine)

    The ecu map is not like stock, because the idle is at 1000revs all the time, that is not normal in a stock ECU, and i compared the map with a LS3 Camaro map and has a lot of differences, including the MAF calibration table.

    I'm thinking about the MAF calibration on the ECU is not for the 4" intake...because the ECU at 1000 revs idle and 40PSI at fuel pressure regulator, is removing fuel through the Lambda sensor like a -8% in the Long trim and like a -3% in the short trim, a lot of fuel, and if i'm not wrong this engine runs with more than 50PSI at the fuel pressure regulator (more that -15% at Long Trim and around -12% at short trim)

    Any idea to check? I will be very pleased
    Best regards

  2. #2
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    What pedal are you using?

    Engine diag-->airflow, "airflow correlation" P0068, set enable to 8192 as a starting point to see if it gets rid of the problem. Don't leave it like this, I just want to see if it helps or not.

    P0102, what's the MAF frequency fail low set to? It's on the same screen as the previous one
    Last edited by schpenxel; 04-25-2016 at 07:10 PM.
    Post a log and tune if you want help

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  3. #3
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    The Pedal is the corvette one. All new and come with the engine and wiring like a "plug and play" set.
    Will test the P0068 and put 8192.

    About P0102, i did not check the frequency, it is with the car running at WOT only...the car is a driftcar and it is not complete so it is difficult test it with me inside.

    Both DTC appears just at the same time!!

  4. #4
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    Hello schpenxel,
    I went to test the value you told me, but our HP tuner version does not have it, my customer has the Standard version, we called to another guy to ask and said the same, may be the problem is the MAF limits/correlation, we send the map to see if he can change it for us.

    I did a log today, and all looks perfect, the maf read something like 470 g/s at the top end when the fault comes.

  5. #5
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    Edit - View - click advanced - close and reopen / - now you should be in advanced view
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

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  6. #6
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    i feel stupid right now...will do

  7. #7
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    Quote Originally Posted by raulhp View Post
    i feel stupid right now...will do
    I think 90% of the people on the board have done that at least once in the beginning
    Post a log and tune if you want help

    VCM Suite V3+ GETTING STARTED THREADS / HOW TO's

    Tuner by night
    CPX Tuning
    2005 Corvette, M6
    ECS 1500 Supercharger
    AlkyControl Meth, Monster LT1-S Twin, NT05R's
    ID1000's, 220/240, .598/.598, 118 from Cam Motion

    2007 Escalade, A6
    Stock

  8. #8
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    Hello schpenxel
    I when to advance view... and i checked MAF Limit Vs RPM table, we have a stock limit of 300 g/s, our engine gets 447 g/s, so i rised the limit to 550 g/s to be sure, after this, no more P0068...

    Now the other DTC, the P1516 and P0102. We were checking the throttle pedal and throttle body wiring and connectors, all looks ok. But i found when i have the problem and our throttle die. If i push the throttle to the floor (84% pedal and 100% blade opening) and then remove slowly a little and try to keep the pedal, our blade goes to close, die and DTCs appear. I think the Gas pedal is broken or have any problem on the potentiometers.

    Both, gas pedal and throttle work perfect until i do this, then i have the DTC and i need erase them.

  9. #9
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    What happens if you set those two codes to not report?

  10. #10
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    i did not tested, will try for you, the owner ordered a new pedal and throttle motor

  11. #11
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    Well, today i tested...if i go to DTC and put to no report...the car goes to limp mode again...but you couldn't see on the Scanner, you could delete them, but you could see them.

    But...i tried another thing. As the problem comes when i request throttle blade to the 100%, i wrote in the software the maximum Opening at 98%....and was solved!!!! I could imagine the pedal or blade motor has a problem and when you request WOT some voltage spike or something happen and goes to limp mode.

    the customer had order a new throttle body with motor, i will swap it to see if the problem comes from there

  12. #12
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    Whatever works! Good idea

  13. #13
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    hi again
    My customer told me that drove for about 20min and the DTC came again, P1516...and no throttle at all. i lowered the m?ximum angle to 95% but still there...

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  15. #15
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    Thanks
    I found it just after wrote this post...i read it carefully and i will do what it says
    Thanks again