Check for 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.
Diagram courtsey of Tmoss and Stang&2birds
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)