Lean

Discussion in 'All Topics, Chips, and Tech for Buicks' started by duber3, Jun 16, 2019.

  1. duber3

    duber3 Well-Known Member

    Hi Eric
    Last year with my 42's injectors, the O2 was always at 760 at the track
    this year I only change my 42s for a set of 60s with a new chip
    My first run the O2 was at 730, I added WOT fuel per the chip and the O2 lowered
    everytime I added wot fuel the O2 lowered, my last run the O2 was at 700 and I had
    KR, can the walbro 340 pump not enough for the 60s??

    Thanks!
    Eric
     
    Last edited: Jun 16, 2019
  2. EricM

    EricM Administrator Staff Member

    The 340 is normally fine with the 60lb injectors.

    So everything else is the same as before? Same combo, same boost, fuel type?

    The basic things we normally check are fuel pressure at full throttle, and make sure the MAF reading (AF on a scanmaster), is hitting 255 at full throttle.

    Also make sure the O2 sensor is good.

    Regards,
    Eric
     
  3. duber3

    duber3 Well-Known Member

    Hi Eric
    Yes everything else is the same, Today I changed the fuel filter just in cases, I opened it and it was like new, so it's not the fuel filter
    I test the car tonight at WOT, the o2 reading was 011 and the engine bugged, I have a good O2 sensor I will try it and check the AF on the scanmaster
    Thanks!
    Eric
     
  4. duber3

    duber3 Well-Known Member

    Finally, I had the time to test the car, changed the O2 sensor, the fuel pressure is good but the AF reading on the scanmaster at WOT was 230 and keep lowering until I let off the throttle, the last AF reading was 210 just beffore I let off
    So does it mean that necessarily the MAF is bad? or it can be something else too
    Thanks!
     
  5. EricM

    EricM Administrator Staff Member

    If your boost is around 15psi or higher, then it should be hitting 255. Either the MAF is bad, or there is a restriction in the intake, like a collapsing intake hose or something.
    If you have a Translator setup, then you can adjust the MAF reading somewhat.
     
  6. duber3

    duber3 Well-Known Member

    I think you were right!!!
    The screen on the MAF have fallen in the air Filter
    Is it enough to influence the air flow??
    I'm running at 26lbs of boost,
    should I install a blowoff valve or can I remove the MAF screen??

    Thanks!
    photo.JPG
     
    Last edited: Aug 18, 2019
  7. EricM

    EricM Administrator Staff Member

    Yes that will cause a bad reading. You need to have the screen for accurate readings.

    Some people have put a few dabs of epoxy around the black ring so it can't be blown out.
     
  8. duber3

    duber3 Well-Known Member

    Still the same issue after reinstalling the MAF screen, I ordered a new MAF plus an alternator, I just discovered that the alternator doesn't charge
    like it supposed to!!
    I will keep you inform
    Thanks!
     
  9. duber3

    duber3 Well-Known Member

    Finally...problem solved, changed the MAF for an LT1 and added the translator, my BLM was never that good, cruising on the highway at 65mph, the blm is at 126.
    There's still a question that remain in my head...I changed ther alternator too, the old one was bad, can a bad alternator played a role in my problem??:confused:
    Also, I did my best time at the track :D
     

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