[Diy_efi] 555 timers
David Cooley
n5xmt at bellsouth.net
Tue Jan 18 14:03:14 GMT 2005
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you can't do it based on RPM alone... that will either run extremely rich
until the engine is put under full load, or run properly until it's under=
a
load and go super lean and melt a piston...=0D
RPM is only used to determine when to fire the injector... you need some
feedback from Intake vacuum, Throttle position etc to determine when it
needs to add more fuel for load. =0D
=0D
-------Original Message-------=0D
=0D
From: James Seabolt=0D
Date: 01/18/05 07:59:50=0D
To: diy_efi at diy-efi.org=0D
Subject: [Diy_efi] 555 timers=0D
=0D
=0D
=0D
You guys got me thinking over the weekend and I think I'm going to give=0D
this 555 timer a shot.=0D
I've had some experience with this chip. I built a timer that would turn =
an=0D
LED on and off and when I was looking through an old shoe box, found the=0D
circuit still hooked up to the breadboard. That was almost 15 years ago!=0D
=0D
It's been so long since my Tech School days so I'm hoping someone will=0D
refresh my memory. If I can put anything to use from my Digital Circuits=0D
class, I'm hoping this will be it. Since I was unable to use my computer=0D
degree. I ended up working at a chemical plant instead after school.=0D
=0D
What I want to do is take the tach signal from the - side of the coil whi=
ch=0D
will be the trigger, feed that into the 555 chip which will pulse the=0D
injector. And use a potentiometer to adjust the pulse rate.=0D
=0D
I want to start out using a Bosch cold start valve since it would be easi=
er=0D
to mount. Perhaps use the throttle position switch to trigger a second=0D
injector under wide open throttle and boost.=0D
=0D
I downloaded some pages on the 555 timer but can't figure out what size=0D
capacitors I need. And what range the potentiometer needs to be.=0D
=0D
The timer chip I have is stamped NE555N. Is this the chip that will=0D
tolerate 5 to 18 volts? Or do I need a different chip?=0D
=0D
Also I'm a bit confused on the reset (pin #4). One schematic shows it tie=
d=0D
to pin #8 (Vcc). Another one shows something else.=0D
=0D
If someone could draw me up a schematic with what components I need that=0D
would be really cool!=0D
=0D
I'm off for the next three days (I work 12 hour shifts) and would like to=
=0D
spend time on my Yugo since it's too cold to do anything else this time o=
f=0D
year.=0D
=0D
Is it possible to build a working fuel injection system by simply=0D
controlling the injector using just a tach signal? I know it probably=0D
wouldn't be able to adapt any better to temperature and altitude changes=0D
than a carburetor but I'm thinking it just might work.=0D
=0D
I'm having my doubts whether I am going to successful at getting my Yugo =
to=0D
accept blowing through a carburetor so I'm looking toward fuel injection.=
=0D
=0D
=0D
James Seabolt=0D
Tennessee, United States=0D
Homepage --->>> http://users.chartertn.net/jseabolt/=0D
=0D
2003 Subaru Baja=0D
1987 Yugo GV=0D
1980 FIAT 2000 "TURBO" Spider=0D
1968 Ford Fairlane 500 (Not a Ford Galaxie!!)=0D
=0D
=0D
=0D
=0D
=0D
=0D
=0D
=0D
_______________________________________________=0D
diy_efi mailing list=0D
diy_efi at diy-efi.org=0D
http://lists.diy-efi.org/mailman/listinfo/diy_efi
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<DIV>you can't do it based on RPM alone... that will either run extremely=
rich until the engine is put under full load, or run properly until it's=
under a load and go super lean and melt a piston...</DIV>
<DIV>RPM is only used to determine when to fire the injector... you need =
some feedback from Intake vacuum, Throttle position etc to determine when=
it needs to add more fuel for load. </DIV>
<DIV> </DIV>
<DIV id=3DIncrediOriginalMessage><I>-------Original Message-------</I></D=
IV>
<DIV> </DIV>
<DIV id=3Dreceivestrings>
<DIV dir=3Dltr style=3D"FONT-SIZE: 11pt"><I><B>From:</B></I> <A href=3D"m=
ailto:turbofiat at hotpop.com">James Seabolt</A></DIV>
<DIV dir=3Dltr style=3D"FONT-SIZE: 11pt"><I><B>Date:</B></I> 01/18/05 07:=
59:50</DIV>
<DIV dir=3Dltr style=3D"FONT-SIZE: 11pt"><I><B>To:</B></I> <A href=3D"mai=
lto:diy_efi at diy-efi.org">diy_efi at diy-efi.org</A></DIV>
<DIV dir=3Dltr style=3D"FONT-SIZE: 11pt"><I><B>Subject:</B></I> [Diy_efi]=
555 timers</DIV></DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>You guys got me thinking over the weekend and I think I'm going to g=
ive</DIV>
<DIV>this 555 timer a shot.</DIV>
<DIV>I've had some experience with this chip. I built a timer that would =
turn an</DIV>
<DIV>LED on and off and when I was looking through an old shoe box, found=
the</DIV>
<DIV>circuit still hooked up to the breadboard. That was almost 15 years =
ago!</DIV>
<DIV> </DIV>
<DIV>It's been so long since my Tech School days so I'm hoping someone wi=
ll</DIV>
<DIV>refresh my memory. If I can put anything to use from my Digital Circ=
uits</DIV>
<DIV>class, I'm hoping this will be it. Since I was unable to use my comp=
uter</DIV>
<DIV>degree. I ended up working at a chemical plant instead after school.=
</DIV>
<DIV> </DIV>
<DIV>What I want to do is take the tach signal from the - side of the coi=
l which</DIV>
<DIV>will be the trigger, feed that into the 555 chip which will pulse th=
e</DIV>
<DIV>injector. And use a potentiometer to adjust the pulse rate.</DIV>
<DIV> </DIV>
<DIV>I want to start out using a Bosch cold start valve since it would be=
easier</DIV>
<DIV>to mount. Perhaps use the throttle position switch to trigger a seco=
nd</DIV>
<DIV>injector under wide open throttle and boost.</DIV>
<DIV> </DIV>
<DIV>I downloaded some pages on the 555 timer but can't figure out what s=
ize</DIV>
<DIV>capacitors I need. And what range the potentiometer needs to be.</DI=
V>
<DIV> </DIV>
<DIV>The timer chip I have is stamped NE555N. Is this the chip that will<=
/DIV>
<DIV>tolerate 5 to 18 volts? Or do I need a different chip?</DIV>
<DIV> </DIV>
<DIV>Also I'm a bit confused on the reset (pin #4). One schematic shows i=
t tied</DIV>
<DIV>to pin #8 (Vcc). Another one shows something else.</DIV>
<DIV> </DIV>
<DIV>If someone could draw me up a schematic with what components I need =
that</DIV>
<DIV>would be really cool!</DIV>
<DIV> </DIV>
<DIV>I'm off for the next three days (I work 12 hour shifts) and would li=
ke to</DIV>
<DIV>spend time on my Yugo since it's too cold to do anything else this t=
ime of</DIV>
<DIV>year.</DIV>
<DIV> </DIV>
<DIV>Is it possible to build a working fuel injection system by simply</D=
IV>
<DIV>controlling the injector using just a tach signal? I know it probabl=
y</DIV>
<DIV>wouldn't be able to adapt any better to temperature and altitude cha=
nges</DIV>
<DIV>than a carburetor but I'm thinking it just might work.</DIV>
<DIV> </DIV>
<DIV>I'm having my doubts whether I am going to successful at getting my =
Yugo to</DIV>
<DIV>accept blowing through a carburetor so I'm looking toward fuel injec=
tion.</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>James Seabolt</DIV>
<DIV>Tennessee, United States</DIV>
<DIV>Homepage --->>> <A href=3D"http://users.chartertn.net/jseab=
olt/">http://users.chartertn.net/jseabolt/</A></DIV>
<DIV> </DIV>
<DIV>2003 Subaru Baja</DIV>
<DIV>1987 Yugo GV</DIV>
<DIV>1980 FIAT 2000 "TURBO" Spider</DIV>
<DIV>1968 Ford Fairlane 500 (Not a Ford Galaxie!!)</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>_______________________________________________</DIV>
<DIV>diy_efi mailing list</DIV>
<DIV><A href=3D"mailto:diy_efi at diy-efi.org">diy_efi at diy-efi.org</A></DIV>
<DIV><A href=3D"http://lists.diy-efi.org/mailman/listinfo/diy_efi">http:/=
/lists.diy-efi.org/mailman/listinfo/diy_efi</A></DIV></TD></TR>
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