A qestion about K&N Drop-ins and the MAF

[WJN333]

Ok so I took my car in for servicing, good shop, I trust the mechanic. He noticed my K&N drop in and told me about a problem he has had on cars that have them and Mass Airflow Sensors. Said he had just had this problem on a Tacoma Prerunner.

When the engine bay heats up, some of the oil on the filter vaporizes and is drawn into the intake. Where it coats the mass airflow sensor. Later small bits of dirt not caught by the filter start to collect on the lightly coated sensor. As the dirt builds up the sensor becomes less effective, lowering the reading and running the motor increasingly lean. Eventually leading to a CEL and I cant remeber the code. On the tacoma he said all he had to do was clean the sensor and then replace the air filter. I doubt this applies to CAIs cause the filter is down where its cool.

Anyone who is using the K&N drop in had this problem? How hard is it the clean the sensor. I get better MPG with the K&N so if I could just clean the sensor periodically instead of getting rid of the filter that would work.

[SC V6]

Its a possible senario... i've never heard of it happening... The sensor is very delicate and should be cleaned with the proper tools... I don't think you should touch the wire inside the sensor.. .I can't remember how people used to clean those

[Elmer]

Weird... never heard of this one, and I've put K&N's in all my cars for years. I was just getting ready to get one for my new car.

Have you asked K&N about it? Seems like they'd know.

[dominoSLEV6]

It doens't seem far out of the realm of possibility, but however on our cars, and most toyotas from what I know, use a kind of "factory cold air intake" that will keep cooler air coming through your filter, and that and that bigass plastic box should be enough to keep it down IMO. If it was a big problem, K&N dropins wouldn't be so big. I think the problem is probably more closely related to people cleaning their air filters and respraying with too much oil than anything else.

-chris

[WJN333]

Never heard anything about this either. Just thought id see if anyone here had this experience. I have not checked with K&N.

[Ian]

What a coincidence, I am on vacation in Texas (I drove out there) and I had to have my MAF changed today. It was full of oil, so it made the car throw a CEL saying it was running too lean. The oil gets on the sensor wires and prevents it from accurately reading the air flow.

They said it was from my cold air intake and the supercharger. I guess over time the oil starts blowing into the MAF. In any event, I just spent $300 that I didn't plan on spending.

They said if I clean my throttle body every year that it would help to keep this from happening.