efi555
ARTHUR OKUN
arthurok at ix.netcom.com
Sun Jan 28 04:03:19 GMT 1996
You wrote:
>
>At 01:50 PM 1/27/96 MDT, Darrell A. Norquay wrote:
>
>>And so it begins. The questions, I mean.
>>I'll try not to pester you too much with this, but it sounds
>>almost too good to be true. I'll be hunting down parts over the
>>next few weeks, and I'll post my results to the list if anyone's
>>interested. Thanks in advance for any info.
>
>Darrell A. Norquay
>
>
>
>Darrel, before you start your holy pilgrimage for discrete
electronics,
>let's kick one more idea around. Back in '87 or so, I built a 555
based FI
>control unit with only one variable resistor controlling the pulse
width.
>The timer was configured in a monostable mode to fire the injector
twice per
>revolution. On the bench, the electronics worked like a charm. I never
got
>around to testing the electronics on an engine with actual injectors.
I
>started reading about how the GM EFI systems worked and those OEM
parts were
>starting to show up in the salvage yards in large volumes at low
prices. I
>convinced myself that OEM was the way to go.
>
>I started having the same questions that are circulating around now
about
>the 555.
>If I were still interested in building an EFI control unit from
scratch. I
>would seriously consider the Basic Stamp microcontroller by Parallax.
With
>8 i/o's, you would have a lot more flexibility than the 555. Imagine:
>
>i/o 1 = injector driver
>i/o2 = rpm input (this could be a permissive to prevent that
theoretical
>engine run away)
> 3 = MAP input
> 4 = MAF input
> 5 = you get the idea....
>
>It's a lot easier to connect the Stamp to your PC and modify the
program,
>than to fiddle with resisters, capacitors, and other discrete devices.
I
>haven't used the stamp yet, but it seems ideal for this application.
They
>are priced around $29 - $39 (I THINK). Check out their web page. One
more
>thing, the Stamp might work best in the astable mode. I'm not sure if
it
>would be fast enough for 'real time' reactions of less than 20 ms.
But I
>could be wrong.
>
>Keep us posted and good luck.
>
>George M. Dailey gmd at tecinfo.com
>
>im thinking of building one using a pic 16 which is the basis of the
basic stamp since i already have a programmer for one
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