Hello. As most of you know (and prolly dont care . . lol) I'm fixing up a 93 NA 300zx slicktop. Ive done almost everything that can be done without pulling the motor down. New coilpacks. New ECU. New plugs. New fuel line, coolant line and vacuum line. New P2 injectors (including P2 conversion on rail) New P2 connectors. New O2 sensors. Plenum was pulled and COMPLETELY cleaned until it was clean enough to eat food out of. Then it was painted so it looked nice n' pretty. All the deletes for an NA were done while the plenum was off, some of them were already done in a half-assed manner so they were completed properly. I even did the coolant re-route slightly differently, much less pipes. It only needs to be connected in two spots if you look at the diagram properly, LOL. Anyhoo, after doing all of this and putting everything back together it still ran exactly the same as it did . . . . like a thai chaff cutter. Overfueling and blowing black smoke etc. As an afterthought we grabbed the AFM/MAF off one of the other Zeds in the shop and put it on mine. Immediately the car ran like it should. Here are the main questions for my own lil database in my head . . . . Is this a common way for a AFM to fail? If not, What are the common symptoms for a AFM failing? The ECU had dead pins (reason for getting a new ECU) one injector had packed it in and 2 of the coil packed were McF**ked. . . . can any of this lead to AFM damage? What are the common culprits for damaging an AFM? thanks in advance . . . . Peace
Mine just failed Age... Some Blowback... Someone else might have some more technical information perhaps....
The hot wire can get coated with crap. Normally from using a oiled filter like a K&N. You can clean them if you are careful.
would an oiled filter possibly kill the hot wire? The pods that i took off it were hillariously dirty and would have done exactly what you mentioned. Also because of the over fueling it has backfired a bit while trying to fix it so this could have also caused some problems but the AFM/MAF was already fubar before then. Ive ordered another one . . .
Backfiring is unlikely to damage it. I'm not sure if oil will kill the hot wire, but it will stop it working properly. You can VERY carefully clean it with some carby cleaner or similar.
Don't care what K&N say, you get enough oil on a hot wire and it won't work properly. If you follow their directions on cleaning and oiling the filter then there is normally no problem. I have heard of several Zeds that have had trouble due to dirty hot wires and all (IIRC) had oiled filters. Anyway, oiled filters aren't legal for road use. Get a Apexi.
Hotwire sensors are fairly fragile and the sensor itself can just mechanically fail, Ie the wire breaks due to prolonged and repeated vibration. if the sensor wire was alredy fatigued, some decent backfires might have been enough to finish the job off quickly. Oil on the sensor, as Chrispy points out, sure messes with its head as it insulates the sensor wire from airflow. L8tr E
oiled air filters can coat the element on a afm after years, same thing happens if you run no filter it gets crud and even water on .... there 20 years old. they will last forever in a vacuum with no dirt or oil or water.. on a car with a air filter setup like a zed they are exposed to the elements
pretty sure we cannot. most other nissans steal from us because the Z32 AFM flows the most. if you use the wrong one from another nissan all it will do is max out and you get fuel cut.
Q45 flows the most But won't fit as it's too big If your clever you can put the hot wire into a larger diameter tube and retune to suit. I've seen Z32 hot wires in 100mm tube.
The MAF I had is dead now anyway. The element looks intact but one cannot be certain there is not a microscopic break in it. There is no chance of cleaning it as it has been tried, it is knackered. The N60 MAF from a maxima is exactly the same as the N62 from our 300zx's but will be rated for a different flow. Im about to order a new one and be done with it . . . LOL. I was gonna buy a second hand one but after reading so much about the hot wire element etc I am just going to buy it new. Peace
Not being able to rev over 2,000rpms is fairly typical. I've had an AFM fail while driving and the ecu just turned the car off at 60kmph! I was like, wtf did the car just die? Pull up and stop and it started again perfectly, rev over 2,000rpm and it spluttered and died again. Limp mode! Nissan are smart, some cars dont do this and proceed to explode when it cannot meter the air no more.
LOL, thats prolly what mine was headed for then! . . It didnt have the common 2000rpm problem, it was sending all McF**ked up readings to the ECU and therefor overfueling which would have indeed led it to . . . explosion.
