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MAF sensor issues


dkpath96
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My mass airflow sensor was wigging out on me last week, causing my pathy to

jerk violently and randomly at any speed. I wasn't sure what the issue was - no

warning lights came on - so I went to the nearest garage (big mistake) and they

ran a diagnostic ($78???). They replaced the MAF sensor (put in a remanufactured

one and charged me $300 - later I found it for $180 reman... :furious: .

 

Anyhow, I am now getting crappy gas mileage (about 4 mpg less). Does the

pathy need some time to "adjust" to the new MAF, or did the mechanic :X

something else up?

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$300 is insanity. I found one for my old 2k2 Sentra SE-R at a junk yard for $100. If I may ask, how did your MAF start acting up? Do you have a CAI? K&N drop-in? Typically MAF's won't bust, unless they're abused (hence, mine went on my SE-R because the CAI's mounting bolt snapped causing it to shake itself to death!) As far as adjusting anything...no, nothing needs to be adjusted. MAF's plug in and your done. The actual sensor in it may be dirty however if it was a ****** rebuild.

It's hard to see in here, but in the middle of here there is a thin piece of metal that hangs down in the middle of the tube and resembles a filament from a lightbulb. If that's dirty, it'll act up on you. Then again, you may just be paranoid about it because your pissed about the $300 :D

(this is an extra MAF from my Sentra)

Dsc01081.jpg

hope that adds some light to your situation.

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I do have a K&N drop-in, cleaned it about 6 months ago...

 

As for how it was acting up, I was driving to town one day and wham, the vehicle

lurched. Then it was fine for a while, then it would lurch again, like it was seriously

just cutting out completely. I feared fuel pump or worse - tranny - and there was

no check engine light. Drove it right in to the closest shop (grr...) and they fixed it.

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I do have a K&N drop-in, cleaned it about 6 months ago... 

 

As for how it was acting up, I was driving to town one day and wham, the vehicle

lurched.  Then it was fine for a while, then it would lurch again, like it was seriously

just cutting out completely.  I feared fuel pump or worse - tranny - and there was

no check engine light.  Drove it right in to the closest shop (grr...) and they fixed it.

Ok. Reason I ask is because sometimes when you clean a K&N and don't wait for it to dry, the oil will collect on that little metal filament, causing the symptoms you describe. Did they test your original MAF before replacing it? A multimeter would have told them if it were really fried or not...did they give it back to you after replacing it?

Edited by navygz19
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No, I didn't get it back... but I will see if they still happen to have it on Monday.

Let me guess, I could have just cleaned it with some rubbing alcohol, and "voila"!

problem solved??

 

Thanks for the info, this discussion board is better than an OBDII diagnostic!! :aok:

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No, I didn't get it back... but I will see if they still happen to have it on Monday.

Let me guess, I could have just cleaned it with some rubbing alcohol, and "voila"!

problem solved??

 

Thanks for the info, this discussion board is better than an OBDII diagnostic!! :aok:

No, not saying simply cleaning it would have definately been the answer to your problems, but it would have been MY first angle of approach ;) That's ok tho...hopefully they will give you back your old one if they still have it. Get yourself a multimeter and test it, OR clean it, re-install it yourself and start your truck...it won't do anything if it's really bad...might throw a code and cause the SES light to come on but it will clear.

 

Interesting how they didn't offer it back to you...I ALWAYS take back original parts, even if all I do is throw them away. Keep us updated!

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Well, the MAF sensor is gone, and I am trying to put it all behind me.

 

I'm hoping I just got a tank of bad gas - when the pathy was jerking so bad I

thought maybe I was out of gas (my fuel gauge has been acting up here and

there) so I filled up at a POS station...

 

Next tank should tell me more about the mpg.

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The Garage has to give you the replaced part back by law I believe. So, I would take that up with them. As for the busted MAF, it really shouldn't cause that kind of performance, unless it was grounding out. That almost makes more sense if the intake was rattling around. So they may have replaced the MAF, when it was really a wiring issue. The wiring issue still exists, but you now have a new MAF which will do nothing for you. I would go back to that shop, as you really got ripped off on the deal.

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Well, the MAF sensor is gone, and I am trying to put it all behind me.

 

I think that's about all you can do right about now. Live and learn I suppose! BTW...how's the Pathy running? Did you go through that original tank of gas yet?

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Ok, I ended up 2.5 mpg under my average of 18, all commuter mileage. It

has definitely rebounded on the second tank back to 18 mpg.

Doesn't sound like enough of a difference to worry about...

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I had a bad MAF too...probably when I was cleaning my TB. Anyways, when my MAF went it caused the truck to run pig rich, which mixed fuel with the oil, so it burned a little oil, which turned into a lot of oil, which turned into oil starvation, so now my truck burns oil when it's cold.

 

Also, it still runs a little rich, but I think that's because the O2 sensor may have become fouled. You can see black smoke in the rearview mirror over 4k rpms.

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I had a bad MAF too...probably when I was cleaning my TB. Anyways, when my MAF went it caused the truck to run pig rich, which mixed fuel with the oil, so it burned a little oil, which turned into a lot of oil, which turned into oil starvation, so now my truck burns oil when it's cold.

 

Also, it still runs a little rich, but I think that's because the O2 sensor may have become fouled. You can see black smoke in the rearview mirror over 4k rpms.

Are you planning on changing the O2 Sensor?

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Are you planning on changing the O2 Sensor?

Haha, yeah, but when the MAF failed 5k miles ago at about 102k miles the mechanic tested the O2 sensor and said it was okay. Next time I'm home in the summer I'm sure I'll have to replace the cat (with a Magnaflow or Carsound) and at least one O2 sensor. I haven't searched yet so I don't remember how many there are, but I think there are 4... :hide:

 

You have no idea, I can hardly change my license plate lights. The whole reason my MAF got fouled up was because of what I did, but that's a long story that was beaten to death in The Garage. Basically, it really screwed up my engine, but it's one tough mother and keeps going. Just waiting for it to crap out, and I don't think it's going to.

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Haha, yeah, but when the MAF failed 5k miles ago at about 102k miles the mechanic tested the O2 sensor and said it was okay. Next time I'm home in the summer I'm sure I'll have to replace the cat (with a Magnaflow or Carsound) and at least one O2 sensor. I haven't searched yet so I don't remember how many there are, but I think there are 4... :hide:

 

You have no idea, I can hardly change my license plate lights. The whole reason my MAF got fouled up was because of what I did, but that's a long story that was beaten to death in The Garage. Basically, it really screwed up my engine, but it's one tough mother and keeps going. Just waiting for it to crap out, and I don't think it's going to.

EDIT: Forgot to add that gas mileage has dropped only a tiny bit (maybe 10 fewer miles on a tank) and no codes have been thrown. If the mileage gets worse or a code is thrown it's replacement time. I have a trusted mechanic in Atlanta, but not in Bloomington.

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EDIT: Forgot to add that gas mileage has dropped only a tiny bit (maybe 10 fewer miles on a tank) and no codes have been thrown. If the mileage gets worse or a code is thrown it's replacement time. I have a trusted mechanic in Atlanta, but not in Bloomington.

Post-Whore :hide:

Just kidding buddy...Anyways, I'll do a search to come across this story of you trashing your TB :D

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Post-Whore  :hide:

Just kidding buddy...Anyways, I'll do a search to come across this story of you trashing your TB :D

I HATE post whores!!! :D

 

I beat you to the search-

http://www.nissanpathfinders.net/forum/index.php?showtopic=7036&st=0

 

which lead to:

http://npora.ipbhost.com//index.php?showto...=20entry89625

Edited by OR99.5Speed
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So how do you know when you are running rich. I cleaned my MAF sensor but I am wondering if I should just replace it. Seems like my MPG have droped quite a bit in the last while. What are some of the signs and how much is a new MAF?

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I believe you can test the voltage on the O2's to see whether you're running rich or lean. I know it says the values in the manual so I can check if you need it.

Yup, that's what the shop did on mine. That's all an O2 sensor does, it's not very complicated.

 

I don't know how to test it, but I would assume hooking it up to a voltmeter.

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