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Old 01-27-2009, 01:24 AM   #25 (permalink)
Coyote X
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Join Date: Dec 2007
Location: Southen West Virginia
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Metro XFi - '93 Geo Metro XFi Convertible
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I know the 10x probe was messing with the signals at the cpu so it is pretty high impedance there. I didn't really look into it much other than notice the 10x probe didn't work and moving on to something else.

I will try building that circuit this weekend if I get time. One thing though is pretty much nothing is going to be completely 100% in all situations except for measuring the injector current somehow >~0.5amp and outputting a voltage for the arduino to see. I don't think anyone wants to cut their injector wire to do that though

I messed with the resistors on mine and with a 22k and a 3.3k on there giving me 25k ohms seems to do the trick. I can make the injector signal jump if I am at idle with the wipers and rear blower on high, then simultaneously turning on the headlights and front blower on high. I can get it to read incorrectly for about one injector pulse till the alternator gets the battery back over 11V. Other than that it seems dead stable at around 25k. 27k ohm resistors are a standard size so I would say just use a 27k if you are lazy and don't want to modify it much.

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