Tech Tip: An Air Filter Is An Air Filter, Right?

from Maryland Z Club
by Mike McGinnis
Banzai Motorworks

What do you mean my $3.00 air filter ruined my $600.00 air flow meter? Both generations of 300ZXs employ a hot wire air flow sensor who's job is to tell the computer the volume of air entering the intake stream. The computer then adjusts the injector pulse width (the amount of time that the fuel injectors remain open) and therefore the amount of fuel entering the intake. The hot wire system uses a thin strand of platinum wire for control purposes. The computer heats the wire to a temp above that of the ambient air. As air flows past the wire its temperature decreases proportionately. The computer is able to use this information to adjust the injector pulse width.

Problems occur when the wire becomes insulated by contaminates causing the computer to receive inaccurate information. The biggest cause of hot wire contamination is the use of off-brand air filter elements. If they don't fit snugly in the air filter housing dust and dirt will enter the intake and accumulate on the wire. They can also shed small fibers that will surely lead to trouble.

So, spending a few more ducats for a Nissan, Fram, Bosch or other quality filter product can help you avoid a very large repair bill.