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Old 04-06-2011, 08:42 PM   #13 (permalink)
dcb
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Not sure you saw this message, it is a caveat about forcing changes to the pulse width directly:

Quote:
Originally Posted by dcb View Post
modifying pulse width has been done a number of ways, most reliable seems to be by modifying the o2 sensor signal, which tricks the ecu into a leaner mixture. If you force the injector pulse width to a different length, the system WILL attempt to compensate, as is.
counting is trivial by comparison.

Here is one discussion from 2008, keyword EFIE:

Quote:
Originally Posted by dcb View Post
Sure it is doable, a basic arduino or clone can handle it if you want to make it easier to get started. You will get the most bang for your buck by focusing on the O2 sensor IMHO, see also EFIE. Some folks have just added (subtracted?) an offset voltage to lean out the mixture, even on the narrow band sensors, but you could also hold the high signal longer or the low signal longer with the microprocessor if you wanted more precise control.

your o2 sensor cannot handle much current (an analog voltmeter used to measure its output can fry it) and is somewhat expensive though, so proceed with caution. And you already know (or will research) all the caveats of running your engine too lean.
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