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Old 11-13-2011, 01:31 PM   #19 (permalink)
California98Civic
Cyborg ECU
 
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Join Date: Mar 2011
Location: Coastal Southern California
Posts: 6,299

Black and Green - '98 Honda Civic DX Coupe
Team Honda
90 day: 66.42 mpg (US)

Black and Red - '00 Nashbar Custom built eBike
90 day: 3671.43 mpg (US)
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Quote:
Originally Posted by SentraSE-R View Post
FWIW, I believe Brucepick's explanation of the fuel injector relay in message 9 of this thread is incorrect.
So you are saying that his description of how the switched and powered side of the relay works is incorrect. But I don't think it changes the general import of the message, does it? He wrote:

Quote:
Originally Posted by brucepick View Post
By temporarily severing the ground wire you disable the relay's internal switch, and it sends out no current from the switched side....

This modification just adds one more place from where the relay's status can be controlled. I can't tell from here whether the computer switches the power to the relay's control side on and off, or whether it severs the control side's ground, basically like this mod does. Either way would disable the small coil, which ultimately means no power going out to the injectors.

The injectors themselves receive constant power as supplied via this relay. They are controlled on their ground side. Each injector has its own ground wire going to the computer. The individual grounds are completed by the computer for small fractions of a second at a time. Each injector will squirt fuel only when its individual ground path is completed by the computer.
I have been wondering if there is any possibility of squirted and unburnt or partially burnt fuel in this scenario. Would show-up as fouled plugs, but would also mean piston damage over time. That's why this update. I want the injectors shutting off more cleanly, and that seems to work best when the revs are dropping, not arcing-up from a 75% load pulse at the moment of cut-off.
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See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.



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