Mass Air Sensor..I need Help, Urgent..

[solaris=amazing]

Ok i thought i corrected the problem by cleaning my intake/throttle plate and mass air sensor. But NO.

Today i went to autozone to have them send the computer a hexidecimal code, to shut off my CHECK ENGINE light, and the guy told me if it comes back on, something is still wrong. 10 Minutes later, the check engine light came on :-(

Now, i go to my mechanic, told him everything. He said the sensor itself could be faulty, and to bring it back tomorrow for him to scan the car. I

How can i tell if the sensor is faulty..?

My mechanic said (because i asked) that my car would most likely stall if i unplug the sensor. I went home, tried unplugging it while the engine was running, and it did not stall or have any effect on the way the engine was running. Doesn't that mean that the sensor is infact bad.

A couple days ago, when i brought it to autozone for them to scan, it said it was the mass air etc. I cleaned the throttle plate and intake, then the sensor. The sensor had a little glob of dirt/mud on it. I cleaned the little hair thin sensors very lightly with alcohol and a q-tip. I'm at a total loss here.

How much do those sensor go for also.? The mechanic told me a rebuilt one is like $100-200...

[danny350]

They're sensitive, it doesn't take much contamination to ruin them.

[curtis73]

They are also very difficult to clean. No matter how much you clean them, the surface of the wires is porous and holds little bits of grease and dirt affecting their performance. I've had so-so luck with cleaning them but after a severe contamination or several cleanings they seem to lose their integrity somewhat.

[foureyedbuzzard]

Exactly what code was stored causing the MIL to come on? Where there any other stored or pending codes? Did the tech graph or measure the MAF output voltage?
The MAF sensor has an output voltage of 0 - 5 vdc which goes to the ECM. Typical idle reading will be .6 to .9 vdc and this voltage will increase with greater airflow(higher rpm & higher load) up to a realistic limit of about 4.5 vdc at full throttle, though this would not be normal driving conditions - I hope. You can check this voltage with a voltmeter. right at the MAF connector if you can identify and access the correct pins on the connector. A voltage LOWER than .45 at idle will set a code, as will any self-checks done through some resistive bypass circuitry built in to the MAF. The MAF circuit basically looks at how much current is necessary to maintain constant temperature in a small heated wire in the presence of a small portion(slipstream) of the intake air. The MAF has a thermistor temp sensor that works in conjuntion with the heater wire. This ECM flow measurement loop also uses the voltage output from the IAT sensor(Intake Air Temperature) in its calculations.

http://www.gatewaycleanair.com/mecha...4/dirtymaf.htm

[solaris=amazing]

Thanks alot guys.. Came back from my mechanic today, the maf sensor is the problem. It only reads .01 at idle, NOT GOOD. It's giving out very little voltage.

The funny thing is, everyone sells these damn thing re-built, even my mechanic, FOR $179.... I went to autozone, and they can get me one for $110, but its rebuilt.

I'm gonna search the net for autoparts stores that sell them new. How the hell do they re-build a hair thin sensor.

[foureyedbuzzard]

Originally Posted by solaris=amazing

How the hell do they re-build a hair thin sensor.

They probably replace the wire, thermistor, circuit board, connector, etc. with all new components. Quite probably the only part that isn't new is the housing. That's why it's cheaper and why there's a "core charge" if you don't return the old one.

[solaris=amazing]

Yeah your right about the core charge, the part i want is $50, and there gonna charge me an extra 30 core charge. The guy said once they recieve my old one, they refund that 30 on my CC.