MAF code 26 problem need help!

Kdubslugga said:

Ive got an issue, on cold start ups it runs like crap, will keep on dying until it reaches about 120 degrees then it starts to smooth out and then runs great at normal operating temp. When i unplugged the mass air meter on cold start ups it runs awesome, I got an old sensor a buddy of mine had laying around at his job i put it in it did nothing. Now I know its not impossible that this was a bad sensor Ill try another one but does this seem like Im in the right direction, what else could it be, car has a code 26 and it runs great when unplugging it, would almost seem like it would have to be a bad sensor, I dunno maybe im wrong???

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Kdubslugga said:

anybody else wanna chime in

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jrichker said:

If you swap sensors, the part number have to match. The MAF body and sensor are designed to be compatible and will not work properly if you put "Sensor A" on "MAF body B". "Sensor A" will only work properly with "MAF body A"

Code 26 - Mass Air Flow out of range – MAF

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).

Look for 12 volts across pins A & B.

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

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hotcobra03 said:

code 26 out of range? ok what is range?
DC4 CHECK VPWR VOLTAGE TO MAF SENSOR
Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

Disconnect MAF sensor.
Key on, engine off.
Measure voltage between VPWR circuit at the MAF sensor harness connector and battery negative post.
Is voltage greater than 10.5 volts?
Yes / No
GO to DC5 . REPAIR open circuit. RESET Keep Alive Random Access Memory (RAM) (REFER to Section 2, Powertrain Control Module (PCM) Reset ).

DC5 CHECK PWR GND CIRCUIT TO MAF SENSOR
Measure voltage between PWR GND circuit at the MAF sensor harness connector and battery positive post.
Is voltage greater than 10.0 volts?
Yes / No
KEY OFF. GO to DC6 . REPAIR open circuit. RESET Keep Alive Random Access Memory (RAM) (REFER to Section 2, Powertrain Control Module (PCM) Reset

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jrichker said:

The output from the MAF sensor is out of range. The tech note explains that if you had read it carefully.

"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"​

Copying a flow chart from someplace isn't real helpful. A proper description in your own words would have given Kdubslugga something more useful to work with.

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hotcobra03 said:

guess im reading the wrong book,,i see range as voltage...the range changes and is measured by voltage change....without battery volts at maf what would be the range?

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jrichker said:

Without battery volts at the MAF, you probably won't get readings that are of any use at all. The MAF sensor has to draw power from somewhere, and that power source is supposed to be the 12 volts for the MAF heater element.

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jrichker said:

Without battery volts at the MAF, you probably won't get readings that are of any use at all. The MAF sensor has to draw power from somewhere, and that power source is supposed to be the 12 volts for the MAF heater element.

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