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




More information about the Diy_efi mailing list