Directly viewing the injector pulses..

[fumesucker]

I've built the interface to read the fuel injectors on our 94 Altima to the sound card input of our laptop and found that for two diodes and a resistor it works quite well actually.. I recorded some waveforms with Audacity, a freeware sound editor, and here are a few pics.

This first one is at a 50 mph cruise. Injector is on when the waveform goes negative.. That's just an artifact of the way I happened to wire the interface.



The next one is a deceleration mode capture.. Fuel isn't shut off all the way but cut to about 1/5 of the normal idle volume.



Here is a capture of a high acceleration mode..



I have more captures if anyone is interested..