# mass air flow sensor cleaning=bad idea?



## bigbobbadoobob (Dec 30, 2005)

I own a 2001 Sentra XE. I'm getting the 'check engine light' which gives me the trouble codes P0171 and P0174 (system too lean). I've used the OBD code reader tool to reset it but the lights keep coming on. It all points to the MAF sensor. I'd like to try cleaning it but if I damage it, it could be costly. So:

1) How are these typically damaged during cleaning and what should be done to avoid damaging them? 
2) What is the best way to clean these things?
3) Is it dumb to even try??

Here in canada, I phoned the dealer and they quoted $690 for a new one! (What a rip-off). I'm thinking of just leaving the car as it is, since it isn't running very badly, but a friend warned me that if the car is truly running lean, then that can cause damage to the valves. 

Any thoughts would be appreciated!


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## xbrandonx (Mar 27, 2004)

don't mess with the MAF, take it to a shop and see what they think needs to be done.


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## bigbobbadoobob (Dec 30, 2005)

continuing to check the net about cleaning MAF sensors, I found this article about cleaning MAF sensors on Mazdas. http://www.mazda6tech.com/index.php?option=com_content&task=view&id=62&Itemid=1

I'd still like to get advice about cleaning MAF sensors on Sentras though...


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## WATSON1 (Jul 9, 2005)

I picked up a used MAF at a salvage yard. When I got it it was covered in oil and dirt, so I got a can of electrical contact cleaner and sprayed the hell out of it. Cleaned it up to looking brand new, put it in, no problems for 6 months. Just make sure it is completely dry before you put it back in if you decide to do it that way.


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## bigern45 (Oct 25, 2005)

have you put in a new fuel filter, or checked for vacuum leaks? there could be other reasons your o2s are reading lean, make sure you cover all your bases. when cleaning out the mass air flow, make sure that you do not touch the element.... you also need to make sure you have good fuel pressure..


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## bigbobbadoobob (Dec 30, 2005)

thanks for the tips! keep them coming. Interesting to note that MAF sensors are a common source of problems on 2001 Sentras... see this link (discovered through the B15Sentra.net forum:

http://autos.msn.com/research/vip/Reliability.aspx?year=2001&make=Nissan&model=Sentra


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## bigbobbadoobob (Dec 30, 2005)

well, I claim victory... i cleaned the MAF sensor using electrical cleaner (the whole can) and there was lots of crud in there. The filament was noticably more shiny after cleaning. After letting it dry (~ 2 hrs), and reinstalling, the car ran better - no hesitation and definitely more power. The engine light has not come back on yet (after 2 days). 

Thanks to those who helped me. I saved alot of $$$.


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## WATSON1 (Jul 9, 2005)

It may be a good idea to check your air filter also, just to be sure there's no trash or anything getting in. MAF's don't just get dirty out of the blue, something had to get to it.


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## bigbobbadoobob (Dec 30, 2005)

I think you are right. I've changed my filter since then. Last time I changed it, the filter was quite dirty. So I learned a lesson... check/change the air filter more often.


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## WATSON1 (Jul 9, 2005)

If you invest in a K&N filter you can clean and reuse it, instead of buying a new one every time. And you'll get a little more power since your car will breath a little better. I have them on 3 trucks and 2 cars.


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## SuperSon (Jan 5, 2006)

Will any electrical cleaner do?My cars been acting up just recently and theres no check engine light on.one member thinks its the maf sensor so tomorrow im going to pull my air box apart on my pathfinder and clean it all out.
I learned the hard way before on my supra when i decided to clean my k&n i didnt bother pulling the sensor out and boy i was lucky enough that i didnt get it really wet but enough for it not to be able to work for almost a week.
Do i clean the whole unit with electrical cleaner or do i have to pull the sensor off the aluminum housing and spray that sensor with electrical cleaner?


Help is greatly appreciated.


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## bigbobbadoobob (Dec 30, 2005)

As far as the electrical cleaner goes... just go to any automotive parts store and ask for it there. Basically you want something that dissolves oily 'crud' without leaving any residue, and evaporates quickly. The stuff I used (i forget the brand name) contains isohexane and 'petrolium distillates'

I'm not sure what you mean about removing the housing, since I don't know anything about Pathfinders. But I know that the less you handle the sensor unit the better (they warn that they are shock sensitive as well). For mine (which is housed in plastic) I sprayed everything on the inside of the housing. Like everyone seems to say... be careful!


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