You'll need:

1 unfolded safety pin, 2 jumper wires, and a DVOM.

Got them?

Good.

Lets begin.

Looking from the FRONT of the car to the BACK of the car... there are 4 wires off the MAF.

See them?

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!

You 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…)

These 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 damage.
---
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.

BACKPROBE 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.

From dan53:

I was unable to get a power voltage reading on pin 3 while testing my MAF at first, but then I did a little research and found that on later model OBDII cars that the engine must be running versus the ignition being just switched to On to get a power reading. This could have saved me about an hour if I knew this! Dan J Reed, I implore you to make a modification to your MAF DIY test and mention this to save someone else the trouble in the future.
"

Modified by Dan J Reed at 9:09 PM 10-2-2008

BBQmotorsports - BUBENGROPEN - LOWERED CARS SAVE GAS! my DIY page -

I survived ShadowConspiracy's Shaved Bay

Now if my car just had a MAF.. HEHE

Euro lips are for people who want their car to "look" low.

http://www.youtube.com/watch?v=Ierw8eAsw_g

BBQmotorsports - BUBENGROPEN - LOWERED CARS SAVE GAS! my DIY page -

I

buy my daily!

nice video, i like when he shoots the meatloaf

and yet another DIY nice work

Quote, originally posted by MrBadwrench »

After doing 3 lines of coke and getting trahshed on PBR, i didn't think my evening could get any worse. Then i opened this thread.

Weird. I'll have to test that on the OBDII ABA I have.

BBQmotorsports - BUBENGROPEN - LOWERED CARS SAVE GAS! my DIY page -

Sorry I dont, but chances are its a 0-5 volt sensor.

BBQmotorsports - BUBENGROPEN - LOWERED CARS SAVE GAS! my DIY page -

Great post Dan. A TEN!

I wish they would "sticky" stuff like this at least for a while.

Tucson Forced Induction
"The welfare of humanity is always the alibi of tyrants." - Albert Camus

Bentley didnt tell me zhit on how to take off the front sway bar for my VR so I looked up Dan and sure enough had one on his site

Thanks, Lito

BBQmotorsports - BUBENGROPEN - LOWERED CARS SAVE GAS! my DIY page -

Good stuff Dan J

xbox live : Unicornasarus

Good choice!

Quote, originally posted by Deutschbag »

What do mk4s have to do with racing?

So you can gain access to the harness pins while the MAF is running.

Otherwise your cutting and hacking a factory harness thats 10 years old at best.

BBQmotorsports - BUBENGROPEN - LOWERED CARS SAVE GAS! my DIY page -