Quote:
Originally Posted by HaveBlue
MAF Fouling.
Oiled Mass Air sensors is pretty much an urban myth. Check out the K&N website for the actual scientific testing they had done.
http://www.knfilters.com/MAF/MAFTestresults.htm
A lot of dealers make a big deal about this because they've been scared into it by the warranty techs. Keep this in mind. A GM dealership has NO way to test a mass air flow sensor. The book tells them to put the MAF on a same year vehicle to see if it's bad. !!
Can it happen? Sure. From over oiling. If a cheap offshore filter has oil on the inside of the bag wrapping the filter than it's over oiled. Don't use it. The biggest culprit is the owner reoiling the filter after cleaning. Ever read the instructions before doing it? You oil a small area and let it wick thru the filter for 30 min. You DO NOT try to get the cotton all red in 30 seconds 
Several manufacturers now list the amount of oil they put on their filters from the factory. It's done by a computerized sprayer. The amount averages 0.6 oz. Very little. |
Good information, and over oiling has certainly been a problem that K&N gets unfairly blamed.
Keep in mind that K&N chose to use this data as proof than oil is not an issue.
Oiled elements are a problem with MAF sensors, GM used a fiber element with oil on many vehicles, including Impala/9C1 Caprice and Camaro. In the late 90s they began using unoiled elements in the C5 Corvette due to MAF shifting.
Minute quantities of oil, yes even a fraction of the 0.6 oz will migrate to the sensing elements over time. The oil isn't the problem, it is the dust that adheres to the oil on the sensing elements that cause the sensor to shift its reading. The factory and dealerships are aware of this, and in most cases it can be easily cleaned with an approved solvent.
It is not an urban legend, a K&N type element will cause a deterioration of your MAF sensor readings over time compared to a dry paper element. It is a trade-off, if you need more airflow and chose to run a K&N pay attention to your MAF readings, and make sure the MAF is clean BEFORE you do any tuning, a big mistake is to "fix" your AFRs when a simple MAF cleaning should have been done first. You won't see it in 10,000 miles, but after 30,000 or more you will see it.