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Maf Sensor

Zach2013

Zach2013

New member
Okay, so you guys seem knowledgeable. I hooked up the lab scope up to my MAF sensor at school and it reads a solid 5 volts across the screen. It doesn't respond to throttle opening at all either. Does that mean that it's shorted internally( that's my guess) or may it just be dirty?
 


These MAF sensors are known to fail due to bad connections inside the unit. I've bought 3 GM cars that had defective MAF sensors that drove the previous owners crazy. (They don't always throw a code, but make the car run like crap.)

I have never had any luck cleaning any of them. I've bought reman units fairly inexpensively though.
 
Zach2013 said:
Cheapest I'm really finding is $120-$150
Click to expand...

Junkyard or craigslist are your friends. Especially the latter, people will part out their cars and sell the whole throttle body for $30 or less. I have a spare L67 MAF on my shelf even now (aka two throttle bodies, one of which is missing a few sensors as they're getting used as needed).
 
you werent measuring it properly.
the Mass air flow sensor puts out a Frequency signal on the signal. it is not a voltage based signal like many foreign cars.

plus without airflow through it you wont find much of a signal....opening the throttle to raise rpm will increase the frequency.

they fracture at the connector to board internally, a gentle (you dont wanna break it if its not broken) flex up and down on the connector should cause it to stumble/glitch if there's a connection problem internally
 
Well, I do know I measured it correctly because a few weeks ago it worked just fine. I did state that it does not respond to throttle opening. I can unplug it and plug it back it and there's no change in the way it running. JY's around here want like $90 for the sensor
 


Hey, Scotty, is there a difference between the 97-98 sensor as opposed to the 99-03 sensor? I was told there was.
 
I would be inclined to agree with turbocharged400sbc. when the maf isn't doing anything the voltage readout will be less than 1 volt. the maf sensor sends a signal to the pcm and the pcm looks for a change in current load to calculate how much air is metering through. if there is no load, there will be no change in voltage, and the voltage being sent to the maf will be low. I think mine reads something like .43 volts at idle. at wide open throttle it still dosent get to 5 volts, but peaks out at 4.~
 
its not a voltage signal....its a switched frequency signal.
the maf gets power and ground...and outputs a low voltage (5v) 0 to ~20khz frequency signal.

so checking voltage isnt gonna tell you **** unless the IGN 1 fuse or ground is bad

the .5 to 5v stuff is for testing the TPS which is an analog 0-5v signal system UNLIKE the MAF/MAP sensors.

i think some of you may be confused on your sensor identifications/testing.

both maf signal and small tps glitches typically require a DSO to capture the waveform/glitches during diagnostics/tap/wiggle testing
a DVOM is usefull for nothing more than checking power and wiring integrity
 


sorry to high jack but how good are cardone maf sensors? i seen one at the pull a part on a bonniville the same year as my gp, looked new for $20
 


alright, thanks man, im going back next week end to pick up a extra tps, and alternator for back up parts and will exchange it for a oem one or just grab the whole throttle body, mine is dirty as hell, when i bought the car they had never changed the air filter in the 8 years they owned it so if iget a trottle body i can clean it well, also what is the best way to pull off the trottle cables? im scared to do mine because i think i will break it
 
theres little clips at the ends. look at em and figure it out. i forget how its on there, its been a while. but they come off easy. took all of 30 seconds of staring at em to figure it out.
 
One of them pops off. You want to pull straight out. You don't want to pull at an angle because they break fairly easily. Should pop right off. The other you need to open the throttle all the way and slip the cable out of the groove it sits in on the arm deal and then there's a ball looking crimp deal on the end of it similar to what is on the handbrake cables on bicycles. This should pop out of the recess that is it in. A small screwdriver may help you pop it out. Just don't pry too hard.
 
Cruise .. push the end of the cable straight off, in line with the cable. It's on a pin.
Throttle.. Unclip cable from the holder then pull some slack and move it around the piece keeping it in the groove. Once that's done..wiggle it toward the back of the engine and you'll have the cylinder that holds it in slide right out.
 
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