MAF Signal / Transfer Problem (Very Weird!) HELP

Discussion in 'Fox 5.0 Mustang Tech' started by KDK1988GT, Jun 20, 2006.


  1. KDK1988GT

    KDK1988GT Founding Member

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    Ok here is my story...

    About one month ago I was having problems with the MAF signal. My car was hesitating and hitching when I was crusing on the highway. This problem went from happening once every ten min at 1st to later it was impossiable to drive the car.
    I ordered a new MAF that was bigger and Calibrated to match my injector size, I entered the meters Flow specs into the TwEECer and made a 30 point MAF Transfer, I played with the MAF signal and got the car running great. The car worked fine and ran great on the highway and in town. Until the other day I started to get this same hitch and hesitation on the highway again and the car became impossiable to drive. I did not change anything with the tune.
    In order to get my car home I unpluged the MAF and ran it without the MAF, I was able to get my car home this way as long as I kept the RPM up.
    When this hitch/hesitation happens I do not have any drop in fuel pressure. But my A/F gauge seems to drop off Lean then come back to normal. I have changed the fuel pump relay also. I unhooked the computer and the MAF meter and cleaned all connections.
    My car was Speed Density orignaly I went out and bought a Mass Air conversion kit from Ford. Which has worked fine up until this year. My computer is a A9S... I have been using the A9L.bin file for the stock/base tune.
    Would my files on the TwEECer be getting corrputed some how? What might be giving me the problem.. do u think that the Mass Air conversion is starting to give me problems? Any help would be great.. sorry so long.
    #1
  2. Daggar

    Daggar New Member

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    What does CalCon say your adaptive control is at when it's running correctly?
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  3. Daggar

    Daggar New Member

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    Clear the KAMRFs then start the car with your desired tune selected. pull codes.
    #3
  4. KDK1988GT

    KDK1988GT Founding Member

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    well in the scalars the max and min adaptive control in my tune that was working fine are 0.621094(MAX) and 0.378906(MIN)
    #4
  5. KDK1988GT

    KDK1988GT Founding Member

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    no data log on that.. Adaptive control... when it was running.

    Where would I find that?
    #5
  6. vristang

    vristang Advanced Member

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    I think Daggar is talking about KAMRFs? :shrug:

    The first step should be to pull the codes though.

    How did you previously determine that the MAF signal was bad before?
    What brand MAF are you using?
    If C&L, did you replace the MAF tube, sample tube, and MAS?

    jason
    #6
  7. KDK1988GT

    KDK1988GT Founding Member

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    I just figured that my MAF was bad.. changed it and that seemed to work for me, but after a couple weeks the prob came back.

    My new MAF is a Professional Mass Air
    http://www.massairsystems.com/METERS.htm

    This is my complete setup..
    http://www.wmsracing.com/pgi-ProductSpec?WMS-HVI86M1
    #7
  8. KDK1988GT

    KDK1988GT Founding Member

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    I still have this problem!!

    I have tryed hard wiring the MAF Meter... and not using the Mass Air Conversion piggy back. I still have this problem of the car not wanting to idle and rev smooth..

    I even just tryed a different computer... still no luck..

    Could something have happened to the new meter that I have?? Has anyone had a Meter go bad and loose its calibration??
    #8
  9. vristang

    vristang Advanced Member

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    The tweecer can randomly corrupt new files IF you are not careful to deselect the "Update Only" box.
    The file corruption is random in what settings it seems to mess up.
    When loading a new tune, ALWAYS make sure this check box is not checked.

    Other than that...
    Have you pulled the codes?
    It could be that the MAF is not the problem at all.

    Are you data logging when the problem occurs?
    What are your KAMRFs like?

    jason
    #9
  10. vristang

    vristang Advanced Member

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    I couldn't get your "complete setup" link to work.
    #10
  11. shewitt

    shewitt New Member

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    kind of having something just like this after i worked on my altinator i went for adrive and my light came on. said something about loss in signal and i saw my a/f go really lean then come back up to normal. the only thing i can think of is a loose wire. if you figure something out let me know.
    #11
  12. KDK1988GT

    KDK1988GT Founding Member

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    up-date!

    Ok here is an update... I ran a data log on the MAF voltage.. the voltage did not drop off to 0V.

    I went out a decided to get two new O2 Sensors... put them in and started the car.. working much much better.. I can rev the car freely and it idles great.

    But I'm having a prob with the HEGO's they are showing LEAN LEAN.. so I go into the MAF Signal Function and richen up the curve.. but no matter how much I richen the curve the HEGO's do not move at all.. Even when I run the car with the TwEECer off and just run the stock tune my Air/Fuel gauge shows me its lean also. Could I have a bad 02 harness?? What might be causing this?? :?

    I have 30lbs injectors and my meter is Cal for the 30lb'ers
    #12
  13. LEE93COBRA

    LEE93COBRA New Member

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    How many miles on the car since clearing the KAMRF's.

    Do you have a fuel press gauge? See anything odd with it?

    When is the last time the fuel filter has been changed
    #13
  14. vristang

    vristang Advanced Member

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    How long did you give the KAMRFs time to compensate for the new sensors?
    I think Lee93 is on the right track there.

    Have you changed the Adaptive update rate table?
    Most people will set the majority of values at either 10 or 3. When I asked why those values were used, I didn't get any straight forward answers.
    Don't change the low load/idle conditions as this can cause some new problems with idle and shifting; leave the bottom 2 lines as they are in stock tune.

    This will accelerate the rate at which the computer makes its compensations.

    I set all of my table to 10.
    Still...
    I have to drive my car to work, and then home again, before the KAMRFs settle down.
    That is a total of about 45 minutes of driving.

    It sounds like you are getting close.

    jason
    #14
  15. LEE93COBRA

    LEE93COBRA New Member

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    Can't remember what my adaptive is set at but we changed it where the kamrf's are moving in about 5-6 miles and moving really good at about 12 miles.

    In regards to his lean condition, it kinda has me concerned because even if it had not been driven enough the KAMRF's would remain neutral not lean. Either his MAF curve is really way off or something is wrong with the car.

    What are your injector slopes set at?
    #15
  16. KDK1988GT

    KDK1988GT Founding Member

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    injector slope are - high 30
    - Low 36
    #16
  17. KDK1988GT

    KDK1988GT Founding Member

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    about 6miles
    fuel pressure is good does not drop
    fuel filter changed about 3 months ago very few miles
    #17
  18. KDK1988GT

    KDK1988GT Founding Member

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    Up Date!

    Ok I think the prob has been.. fixed!

    I was having the lean prob.. and I could not get the 02 sensors to dance around at all...

    I traced my wires from the 02's all the way into the computer... I figure out that I had a short in those wires... so I ran to new wires to the computer from the 02 sensors..

    Now the car's Air/Fuel gauge is dancing around. and the HEGO's are moving real good now.. and the car works much better.

    Just figured that I would give an update.. thanks guys.. :nice:
    #18
  19. shewitt

    shewitt New Member

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    I had just about the same thing but i was using a ugeo gauge and it was messing with my computer. Put back the factory O2 and no more problems.
    #19

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