Hepl Please MAF Problems

Discussion in 'Fox 5.0 Mustang' started by 92trunk, Apr 28, 2005.

  1. 92trunk New Member

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    I scanned Codes and got code 66 which is MAF sensor. I cleaned it with carb cleaner then q-tip/Alcohol. I still get the same code 66. All wires are intact plus making good connection. What could the problem be?
  2. Daggar New Member

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    The problem "could" be that you've fried the sensing element. Brake cleaner is a 'no-no'.
  3. 92trunk New Member

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    so if it messed up where can I replace it? Like dealer or pep boys? I am going to be doing mods (h/c/i) soon so I might as well get a performance unit now. Whats a good start for me for now that can be upgraded later as airflow increases?
  4. Daggar New Member

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    Click on the link in my signature for the new Pro-M site. Give those guys a call and tell them what you have and where you're going with your combination. They can make a suggestion for size and brand and recalibrate it to specifically meet your need. You may also want to consider sending them your old one to repair if you're not ready for you HCI yet. Could save you some $$ in the long run just to reuse what you've got until you're ready to get a better one.
  5. 92trunk New Member

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    Thanks Daggar Ill give them a try.
  6. jrichker StangNet's favorite TOOL

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    Code 66 MAF below minimum test voltage.
    Insufficient or no voltage from MAF. Dirty MAF element, bad MAF, bad MAF wiring, missing power to MAF. Check for missing +12 volts on this circuit. Check the two links for a wiring diagram to help you find the red wire for computer power relay switched +12 volts. Check for 12 volts between the red and black wires on the MAF heater (usually pins A & B). while the connector is plugged into the MAF. This may require the use of a couple of safety pins to probe the MAF connector from the back side of it.

    There are three parts in a MAF: the heater, the sensor element and the amplifier. The heater heats the MAF sensor element causing the resistance to increase. The amplifier buffers the MAF output signal and has a resistor that is laser trimmed to provide an output range compatible with the computer's load tables.

    The MAF element is secured by 2 screws & has 1 wiring connector. To clean the element, remove it from the MAF housing and spray it down with electronic parts cleaner or non-inflammable brake parts cleaner (same stuff in a bigger can and cheaper too).

    The MAF output varies with RPM which causes the airflow to increase or decease. The increase of air across the MAF sensor element causes it to cool, allowing more voltage to pass and telling the computer to increase the fuel flow. A decrease in airflow causes the MAF sensor element to get warmer, decreasing the voltage and reducing the fuel flow. Measure the MAF output at pins C & D on the MAF connector (dark blue/orange and tan/light blue) or at pins 50 & 9 on the computer.

    At idle = approximately .6 volt
    20 MPH = approximately 1.10 volt
    40 MPH = approximately 1.70 volt
    60 MPH = approximately 2.10 volt

    Check the resistance of the MAF signal wiring. Pin D on the MAF and pin 50 on the computer (dark blue/orange wire) should be less than 2 ohms. Pin C on the MAF and pin 9 on the computer (tan/light blue wire) should be less than 2 ohms.

    There should be a minimum of 10K ohms between either pin C or D on the MAF and ground.

    See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)

    http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

    http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif

    To clean the MAF, remove the MAF element and gently spray it with electrical contact cleaner. You can also use non-flammable brake parts cleaner (same chemical in a bigger can & cheaper too). Let it dry and put it back in.

    http://www.autozone.com/servlet/UiB..._us/0900823d/80/19/59/5a/0900823d8019595a.jsp
  7. sf93 New Member

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    I pulled my codes last night from my 93 notch and got a 66 also. I cleaned the meter with electrical cleaner and alcohol, no difference. So I did all the checks that jrichker listed everything checked out but 10K ohms between either pin C or D on the MAF and ground. does this mean the meter is shot? Forgot to mention it's a stock meter.

    Thanks :D
  8. jrichker StangNet's favorite TOOL

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    The sensor has probably died a sad death. A new one will cost $60-$85. Maybe it is time for a trip to the junkyard...
  9. sf93 New Member

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    Thanks jrichker I got a new one at Auto Zone it was $77. Replaced it got rid of the code 66, and now the car feels alot more responsive. The junk yard thing was a good idea but the yards around here don't seem to keep anything over 5 years old. What a shame. :notnice:

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