unplugged MAF test question

[MMAFIGHTER121]

To see if my MAF was shot, and causing my p0430 (all 4 O2s are new and no vacuum leaks under the hood) I unplugged it and turned the car on, and nothing was different. Since I already had a trouble code its hard to tell if I threw a new one - but to double check it I drove it up and down the driveway quickly and the drive was still the exact same. Does this sound like my MAF is gone? Or would I need to drive the car further to see if there was any change in driving quality?

 

[MMAFIGHTER121]

scratch this... i think... i hooked up a multimeter to the blue/white wire coming from the MAF plug and revved the engine a bit and the voltage jumped and settled accordingly... doubting the MAF is bad.. guess I gotta drive it out to the shop and swap around the 02s... even though all 4 are almost brand new... if they're under warranty I might just take all 4 out and trade them to be sure. Is the blue/white wire the correct one to take this reading? what are the correct voltages? at idle its around .5 - since I was revving from under the bay in N I could only hit the 3K limiter and it only jumped to under 3V.

 

[oddball]

Might be worthwhile to invest in a OBD reader. As discussed recently, the el-cheapo bluetooth ones are easy to get ahold of, and there are free and cheap phone apps now. Then you can watch the MAF readings from the PCM and go from there.

 

[joegr]

Might be worthwhile to invest in a OBD reader. As discussed recently, the el-cheapo bluetooth ones are easy to get ahold of, and there are free and cheap phone apps now. Then you can watch the MAF readings from the PCM and go from there.

Since he's looking at the fuel trims, I assume he does have a scan tool.

 

[oddball]

Since he's looking at the fuel trims, I assume he does have a scan tool.

Agreed, but then why directly measure the MAF output and not correlate to the PCM interpretation?
I didn't notice his other thread about having the trim numbers until later. And I'm not thoughtful enough to correlate folk's multiple posts for them.

 

[joegr]

Agreed, but then why directly measure the MAF output and not correlate to the PCM interpretation?
I didn't notice his other thread about having the trim numbers until later. And I'm not thoughtful enough to correlate folk's multiple posts for them.

That's true. I always graph the MAF reading with the throttle position and the engine speed readings to see if it makes sense.

 

[MMAFIGHTER121]

I have access to my friends scan tool, but I can't always have immediate access to it, sorry for starting a second thread, I just needed to have a complete write-up of the issues and steps rather than knocking them off one at a time.

 

[oddball]

Hey, it happens.
All you have to do is "forget" to return the tool. It helps if there's a huge mess in your garage. "It's in there somewhere........."

 

[MarkVa1]

had the exact same issue...

Disconnected the MAF sensor and it runs... cancelled the tow truck and alleviated the headache ... this site saves the day for me (again)!