My car is running lean at WOT

Discussion in '94-95 5.0 - Specific' started by JJhirsch, Jun 17, 2014.

  1. JJhirsch

    JJhirsch Member

    Messages:
    244
    Likes Received:
    3
    Joined:
    Sep 6, 2010
    Location:
    White Bear Lake, MN
    1994 Mustang GT

    My dyno sheet showed a straight 14 air/fuel from 3500 to 5500RPM. The timing is set at 12degrees and i just noticed at WOT 4000-5500RPM i can hear little pinging.

    What i think is causing it is my 73mm Pro-m MAF and i dont have my stock one. Is there something that i can do without getting a tune? Maybe a adjustable fuel pressure regulator?


    Thanks JJ
     
  2. RichV

    RichV Well-Known Member

    Messages:
    4,227
    Likes Received:
    247
    Joined:
    May 6, 2012
    Location:
    CO
    You need to provide some more info before you get help.

    What's the combo? Stock with a 73mm MAF? Why?
     
  3. JJhirsch

    JJhirsch Member

    Messages:
    244
    Likes Received:
    3
    Joined:
    Sep 6, 2010
    Location:
    White Bear Lake, MN
    It is with a bbk cold air intake because stock size MAF is 60mm? This Pro M is for better air flow. The owner before me put a JET chip in. Should I uninstall the Jet chip?
     
  4. Addermk2

    Addermk2 Well-Known Member

    Messages:
    2,505
    Likes Received:
    32
    Joined:
    Mar 7, 2006
    Yes.
     
  5. RichV

    RichV Well-Known Member

    Messages:
    4,227
    Likes Received:
    247
    Joined:
    May 6, 2012
    Location:
    CO
    Not sure on the Jet chip, ditch it. What #s did you make on the dyno?

    Can you put the stock MAF back in? The restriction on these motors is not the MAF when all stock.
     
  6. Addermk2

    Addermk2 Well-Known Member

    Messages:
    2,505
    Likes Received:
    32
    Joined:
    Mar 7, 2006
    Stock maf is 70mm.
     
  7. slow90coupe

    slow90coupe Well-Known Member

    Messages:
    1,969
    Likes Received:
    104
    Joined:
    Jan 3, 2012
    Location:
    Advance, NC
    Shoot 14 is not a bad AFR. That's much better than my car was stock. When I hooked up my wideband to my car (it had nothing but exhaust at this time) it showed 16.5 afr, and the car was driven for thousands of miles like that. It's never a bad idea to get a tune though.
     
  8. Addermk2

    Addermk2 Well-Known Member

    Messages:
    2,505
    Likes Received:
    32
    Joined:
    Mar 7, 2006
    14 at wot is terrible.
     
  9. Monsterbishi

    Monsterbishi Member

    Messages:
    182
    Likes Received:
    16
    Joined:
    Feb 12, 2006
    Location:
    Christchurch, New Zealand
    Any leaner than 13.2:1 at WOT and you're heading into trouble territory.

    Also, keep in mind that there are plenty of times when detonation/pre-ignition is not audible to the human ear.
     
  10. Musturd

    Musturd Legend

    Messages:
    9,111
    Likes Received:
    598
    Joined:
    Feb 12, 2011
    You guys stayed in it when the air fuel was at 14-1 smh .... Some people shouldn't tune or dyno cars ... Like adder said ditch that chip ...