Tap an extension wire from your injector wire and run it into the passenger cabin to your multimeter. It's AC voltage.
Actually, the voltage across the injectors is DC. It is a square wave that varies from 0V to +12V. But, since it never becomes negative, it is not AC. Of course, using the AC setting on a DVM will also give you a reading. In any case, what you are looking for here is actually 0V upon deceleration.
Originally Posted by R.I.D.E.
The last of Nissan's NAP-Z 4 cylinders that had a carb, had a heated screen under the base of the carb to better emulsify the fuel air mix. Also fuel shutoff on deceleration, and reed valves in the air cleaner that allowed air in to the exhaust under DFCO type conditions.
I still have nightmares about the NAP-Z from time to time. Let's just say that I was shedding no tears the day that motor finally went out of my life. Of course, the rest of the truck was really no better.
I did some research on ALLDATA and on a 90 and 91 civic si (I'm guessing its the same for all 88-91's). when you let off the throttle completely the ecu cuts off the injectors until the rpms reach 850.
so, right there, this is a great way to increase mileage. instead of putting the car in neutral and using gas, you can take your foot off the throttle and use no gas. it's like EOC'ing but you don't have to restart the car, loose power brakes, put extra load on the starter, battery etc. starting the car a lot more then normal. well, maybe not an extra load, but wearing the parts out faster then normally would.