K&N Air Filter

[drooler]

I've owned by Focus SE for over a year now. One of the first things I did when I bought the car was buy a K&N Air Filter as the car was due to go on a road trip.

After a recent trip to the dealer to fix a hesitation problem (110,000 kms now) the dealer noted that the air filter could conflict with the MAF sensor. I was also told that the NGK spark plugs I had installed were not recommended for Ford vehicles. I've used these spark plugs on all my other vehicles with no problems reported. The vehicle was given a tune-up, new fuel pump and the injectors were flushed.

Has anyone seen or heard of evidence to support the dealer's claims about my filter and spark plugs?

Any thoughts or comments would be appreciated.

[Sponsor]

[sidney61199]

The dealers want you to use ford/motorcraft everything. Spark plugs, filters, oil, etc... This is just a line that he was tought when he started working there. I wouldn't worry about it as long as all the specs of the parts in question match up with what ford suggests.

[Mac98SHO]

The only thing you MIGHT have to worry about is if you ever over charge the filter, this tends to gum up MA sensor... Its a simple fix, dissconnect it and clean it with carb cleaner and let dry thoroughly out of vehicle before installing it back in the car.

[soffiler]

Originally posted by drooler
I've owned by Focus SE for over a year now. One of the first things I did when I bought the car was buy a K&N Air Filter as the car was due to go on a road trip.

After a recent trip to the dealer to fix a hesitation problem (110,000 kms now) the dealer noted that the air filter could conflict with the MAF sensor. I was also told that the NGK spark plugs I had installed were not recommended for Ford vehicles. I've used these spark plugs on all my other vehicles with no problems reported. The vehicle was given a tune-up, new fuel pump and the injectors were flushed.

Has anyone seen or heard of evidence to support the dealer's claims about my filter and spark plugs?

Any thoughts or comments would be appreciated.

Any professional tech that sees dozens of vehicles every week, hundreds per year, will tell you horror stories of K&N filters. It is not the filter that's bad, it's the overzealous owner that soaks it with oil after cleaning. The excess oil contaminates the MAF. That's exactly what the dealer is trying to tell you. It is not generally a problem IF the filter is oiled correctly, but apparently enough people mess it up to leave a bad taste with most tech's.

Spark plugs - I know many professional tech's (from another forum I'm on) who automatically diagnose EVERY driveablity complaint by checking plugs, and putting in the manufacturer-recommended plugs automatically before they even try to do anything else to the car. Some will claim that whenever they find Bosch Platinums, 90% of the time the stock plugs will fix whatever the customer was complaining about. That might be an exaggeration, I don't know, but it illustrates the point. Ignition systems these days are highly engineered right from the factory, and attempts to install aftermarket ignition parts stand more chance of screwing something up than anything else.

[sidney61199]

That is true about the K&N, don't oil it till it drips (common sense). The spark plug issue, as long as the gap is the right size and they are brand name plugs I still don't see how there could be a problem.

[soffiler]

Originally posted by sidney61199
That is true about the K&N, don't oil it till it drips (common sense). The spark plug issue, as long as the gap is the right size and they are brand name plugs I still don't see how there could be a problem.

You have no clue how much engineering goes into the lowly spark plug, obviously. There are serious issues with heat-transfer and with electrical parameters. To maximize spark energy, the plug's electrical characteristics have to be matched to the coils. To control the temperature at the tip of the plug, heat-transfer has to be on the money. Factory engineers take all of this into account. Aftermarket companies create cross-references to OEM plugs using whatever they have that happens to be "close". They don't typically tool up a whole new design. So, depending on who it is, and how extensive their existing product line is, they might or might not have a plug where "close" is close ENOUGH. Bosch Platinums in particular are notorious for messing up an engine that would otherwise run normally on OEM plugs. I actually haven't heard of NGK plugs causing any problems in a Focus engine. But the best advice remains to stick with OEM components for all ignition and emission-related systems.

[sidney61199]

"You have no clue how much engineering goes into the lowly spark plug, obviously", no I don't. This is one of the things on my list I must study before being labeled "all knowing". obviously you have already acheived that status. All I'm saying is if you go with a brand name and you match the part number up with the car you have the temp of the plug, spark, and gap should all be compatiable with your car. If it was not every person across the US (maybe canada) who bought that plug for there car/focus would experince problems. There are alot of people in the US and Canada and alot of focus's so what you are saying just makes no sense.

[microtonal]

Not all plugs are made the same. Inform yourself with some knowledge. This article has some basics.

Click here

[denzillion]

I have no intension of getting my filter oiled for that reason. I will buy a new filter for just $30.00 than go through the oiling process.

As for spark plugs, I used Autolite Double Platinum gapped to .65mm with Screaming Demon/Live Wires Ignition Kit. I have yet to have any problem nor dealer gives me crap during the check-ups. My car runs smoother since the installation.

[sidney61199]

I'm not going to waste my time to look at that link due to the fact that I do agree with what is being said about the spark plugs but you are not looking at the other side of the argument that if this was a common problem among popular brand name plugs then this would be an problem sweeping the nation. I'm sure that there are some problem plugs but the majority will not cause any problems if you use the correct part #.