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That is about what I was thinking after digging around a bit. I should go out and get a video of the signal after the zener and resistor so we can see exactly what the avr is seeing. Each line is 2V and the spike that goes off the top is 14V. The middle line is 4V and after the second spike it is around 5V. It really doesn't make sense because the 0V pulse is always the same size then it spikes to 14V then goes to 4V and the 4 volt is as long as the pulse width reported on the ALDL plus ~0.5ms. But then to close the injector I would figure it needs more than a tiny spike at 14V before sitting at 5V. I always assumed a closed injector should read 14V since it is switched on the low side.
If it is a peak and hold injector that means probably a good bit of the GM TBI cars use the same type of injectors and it might be something that needs checked on a few other engines. I will check with some neighbors and see if I can find any other TBI engines around here.
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