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Thread: MAF vs Speed density settings

  1. #1
    Tuner
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    MAF vs Speed density settings

    I cant get a MAF reading from my HP tuner, it never moves just a constant 3.12 if I remember right? I have double checked the wiring and replaced the MAF sensor, no change. I was told to make sure it wasnt set to speed density, it suppose to be in Engine Diag. but I can find it under that name. what am I missing? the MAF sensor is a 5 wire Granatelli. thanks for the help.

    LT1 24X LS1 conversion

  2. #2
    Tuner in Training
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    Feb 2014
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    When you say you can't get a reading do you mean in the scanner? Even with a speed density tune the MAF will still log values, the PCM just doesn't use them. Is that Granatelli MAF one of the compensated ones?

  3. #3
    Tuner
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    MAF sensor part number 350112C, the HP tuner doesn't show any change or values in the MAF reading, it stay constant at 3.12. thanks for you help

  4. #4
    Senior Tuner
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    Log MAF Hz.

  5. #5
    Tuner
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    Ok I bought the Greg Banish DVD and it is great, I programmed for MAF to log in Hz, but still no reading from MAF meter in Hz, or Grams per, alsp no IAT or ECT reading on HP tuner. MAF reads a constant 3.27 in grams per. I am beginning to think my ECM is not reading it, is that possible?
    The problem is When I rev to 2000 rpm my afr goes max lean and stall really hard, I unplugged the MAF sensor which os a 5 wire Granatelli, and it revs great and actually runs really good, but when I run down the road with it unplugged it leans out at 2000 rpm again and wont run, then I put back in neutral and it revvs great again. I am posting the tune and two logs, one with MAF sensor plugged in the other with it unplugged, I have been reading and studying for 2 weeks and I don’t know what to do, I would take it somewhere but no one with in 100 miles and with out it reading MAF I am afraid they cant tune it. Thanks for any help.

    95 T/A LT 1 with 24x LS1 PCM swap. 383 forged, 195 AFR heads, 11.4 comp, 238/246 608/618 110 lsa comp custom cam, 36 lb Bosch injectors, 58 MM TB, Pacesetter LT, 4l69e 3600 circle, 9in 390 gears,]


    43937[/ATTACH]LT1 LS1 log Park and MPH 2nd.hpl[ATTACH]43939
    Attached Files Attached Files
    Last edited by 540gts; 04-17-2014 at 11:45 PM.

  6. #6
    Senior Tuner
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    Verify that the yellow wire on the MAF goes to pin 31 on the red PCM connector. Verify the pink wire on the MAF has +12v. Verify the black wire on the MAF goes to a good ground.

  7. #7
    Tuner
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    Yes I triple check these wires and I have tried 2 MAF sensors.