Step 1 - Throw antiquated worthless system tests in the Bentley boat anchor in the trash.
1 unfolded safety pin, 2 jumper wires, and a DVOM.
Looking from the FRONT of the car to the BACK of the car... there are 4 wires off the MAF.
Good, unhook the MAF the connector.
Ground one side of your meter to the intake manifold.
(NOTE IT WILL STAY GROUNDED FOR ALL THE TESTS IN THIS SECTION!)
Take your safety pin and stick it into the FRONT of the MAF harness. Insert it into PIN 3.
Turn the Ignition ON in the car. DO NOT START THE CAR, JUST TURN THE IGNITION ON!
NOTE!! SEE BOTTOM OF PAGE!!!)
should get 12 volts or higher. (Battery voltage). If not, check the ECU
and harness wires back at the ECU. This is the 12 volts sent to the MAF
from the ECU to power the MAF.
TURN THE CAR OFF.
Set the meter to read OHMS. LEAVE THE CAR OFF!
Next, move the safety pin to pins 1 and 2. (do one at a time, same test…)
are the internal grounds for the sensor, power and signal. You should
get LESS then 3-4 ohms on BOTH pins. If you get MORE then 3-4 ohms
check the harness for breaks or opens, or the connector at the ECU for
Last test, Pin 4.
MAF signal return to ECU.
Remove your safety pin from the MAF sensor harness.
Set the DVOM to read Volts DC again.
Plug the MAF sensor back in.
the RED wire, PIN 4 on the MAF sensor. Use the safety pin to SLIDE the
probe down the wire into the connector base. The point is NOT to break
the wires insulation.
START the CAR. Yes, RUN the CAR. Yes, with the safety pin JAMBED into the wire harness.
Voltage at IDLE should be around .9 volts DC.
Use this handy, dandy chart as a guide:
Idle .9 volts.
2000/3000 RPM 1.5 volts.
3000/Wide Open = up to 3.8 volts.
Note the speed at which the MAF can respond to the changes and airflow.
If your MAF is slow, or lazy, or does not match these values. Good chance its bad.
Modified by Dan J Reed at 10:46 PM 6-15-2007
IMPORTANT NOTE! HEY DUMMY!! THIS IS FOR AN OBDI
CAR! OBDII CARS ARE TESTED THE SAME WAY.. EXCEPT THAT AT THE MAF IS NOT POWERED
UP UNTIL THE CAR IS RUNNING!