Afm stands for Air flow meter, occasionally known as MAF. Its what the computer uses to measure the quantity of air entering the engine to determine how much petrol to inject and how much ignition timing to apply.
What?s a Z32 afm? Why would I need to upgrade to one?
The z32 is a very common upgrade with Nissan cars. They are generally upgraded on those cars more since they support larger amounts of power compared to the stock afm.
How does at faulty Afm cause the engine to detonate/ping?
If it reads less air than is actually entering the engine, the ECU puts less fuel in, and while it also sees less air it also thinks less load which is bad as the timing generally high in those areas on the map, both bad, the engine pings/knocks.