Injector control

[Greg Hermann]

>> >GM is 1/65536 or 1/65517 of a second.  So, about 15 microseconds.
>> >
>> Thanks, Ludis. To me, this means that, if trying to use a GM unit in a real
>> hipo application, NO WONDER it is tough to get a particularly good idle!!
>
>But watermelons don't have handles!  Ie, unrelated issues.
>
>15uS resolution sounds pretty damn good when you figure the
>injector is firing, what...maybe 60 times/sec?  The dynamics
>of the injector itself are a much greater concern--and this
>is making the (often false) assumption that your sensors are
>giving you usable data at idle.
>
>-greg

Nope--more like five or six squirts per second per injector at idle. And a
1.5% adjustment increment  (15/1000 if idle pw is 1 ms.) equates to a  0.2
change in a/f ratio. If your engine is stock, and uses small enough
injectors to idle with a 2ms pw, then you would have a .75% adjustment
increment (0.1 to the a/f ratio) , and you are a lot closer to what I think
you need to have in order to get things to behave properly.

I do not disagree at all that you need to have good, clean sensor output
signals at idle to have a prayer, but just am trying to point out another
factor that might be giving the sensors a bad rap undeservedly!

If this factor is not eliminated, and, in general, it does not appear that
it has been, I think that it could easily be a big part of the problem!

For me personally, I have realized that there is one more thing well worth
paying very close attention to when choosing an ecu. Also, I would be
strongly in favor of trying to make the 332 project capable of making 4, or
even 2 micro second increment adjustments to injector pulse width if it is
at all possible!

Regards, Greg