K & N air filter and Mass Air Sensor

K&N Filters cover the air sensor with oil as the air passes over the filter. Friend had the same problem with his Tacoma. Dealership told him to remove it for this very reason. He never got any Increase in MPG. Just a bunch of problems.

chances are the k and n will cover the mass air flow with dirty oil as well as the throttle bore, iac, intake, pistons, piston walls, ect......throw that piece of crap away. If your racing the p/u down the drag strip and you worry about it not getting enough air, take the filter out. driving down the road it will not make any difference. use a regular air filter and change it when its dirty.

I doubt it happened in 2 weeks. But I agree with your dealer and the other posters that the oil from a K&N filter isn't good news.

Without active feedback in your fuel control a free-er flowing air filter will lean the mixture, usually resulting in better MPG. Its nothing that could not be done by retuning the carburetor.

As things stand you have an active feedback control loop regulating fuel. The O2 sensor and the MAS sensor. Its going to feed the same air/fuel ratio that *it* wants to, no matter what air filter. If the air filter provides less restriction then you will automatically provide more by lifting your right foot.

If you compare your K&N to paper filter you'll see far fewer pleats (folds) in the K&N. That means there is much less surface area in the K&N, yet they claim less restriction. For less restriction there must be more hole area in that smaller K&N surface than in the much larger paper filter surface. The K&N apparently has larger holes, resulting in less filter action. It needs a healthy dose of oil to span the hole gaps. I'm convinced a K&N passes more dirt.

The real solution for "less restriction" (as if that is a real problem) would be to us a larger air filter. The Porsche 928 uses a huge air filter for that very reason.

Here's a bulletin on oiled air filters that someone posted in a group last year.

Bulletin On Excessively Oiled Air Filter Elements:

Info - Automatic Transmission Shift, Engine Driveability Concerns or Service Engine Soon (SES) Light On as a Result of the Installation of an Aftermarket Reusable, Excessively Oiled Air Filter #04-07-30-013 - (03/05/2004) Automatic Transmission Shift, Engine Driveability Concerns or Service Engine Soon (SES) Light On as a Result of the Installation of an Aftermarket Reusable, Excessively Oiled Air Filter =A0

2004 and Prior Cars and Light Duty Trucks 2003-2004 HUMMER H2 =A0

DO THIS First, Inspect the vehicle for a reusable aftermarket excessively oiled air filter =A0

DON'T DO THIS

DO NOT repair under warranty if concerns result from the use of a reusable aftermarket oiled air filter. =A0

The installation of an aftermarket reusable, oiled air filter may result in: =A0

a.. Service Engine Soon (SES) Light On =A0

b.. Transmission shift concerns, slipping and damaged clutch(es) or band(s) =A0

c.. Engine driveability concerns, poor acceleration from a stop, limited engine RPM range =A0

The oil that is used on these air filter elements may be transferred onto the Mass Air Flow (MAF) sensor causing contamination of the sensor.=A0 As a result, the Grams per Second (GPS) signal from the MAF may be low and any or all of the concerns listed above may occur.=A0 When servicing a vehicle with any of these concerns, be sure to check for the presence of an aftermarket reusable, excessively oiled air filter. The MAF, GPS reading should be compared to a like vehicle with an OEM air box and filter under the same driving conditions to verify the concern. =A0

Transmission or engine driveability concerns that are the result of the installation of an aftermarket reusable, excessively oiled air filter are not considered to be warrantable repair items.

K & N air filter and Mass Air Sensor Group: alt.trucks.chevy Date: Mon, Mar 13, 2006, 10:26pm (EST+5) From: snipped-for-privacy@insightbb.com (prfarms)

2004 Z71 5300 engine. 13 to 15 MPG on 2 lane highways 90+ mile runs What is the chance that a K & N air filter will short out a mass air sensor? Installed a K&N air filter in an attempt to increase mileage (no difference) and two weeks later took it to the second dealer for poor fuel economy and they found the mass air sensor burnt out. Said it was caused by the K&N. They warrantied the sensor, put back in a regular filter and I can see about 2 MPG improvement. Should I try the K&N again? Could it help any?

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% "So why do I drive a big SUV? It's because I have to haul numerous people and things to places." ~ R. Lee Baxton ~

I've never see one positive word on the K&N filters. How the hell do they keep selling them? And big bucks, too!!

Well I'll give you one, my 91 S-10 Blazer 4.3, 267,000 miles has had one for most of its life. But then its a throttle body injection, not multi port so there is no mass air flow sensor to gunk up. Carb and throttle body ok, but never on anything with a mass air flow sensor.

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