An Engine can still "run" in an absolutely atrocious state of Tune,
this is the only reason that there is any reason to even consider the 555 as any part
of a Fuel-Injection/Ignition-Control-System.
If You are simply "wanting to see if You can make it run", more power to ya,
but if You expect the Engine to provide reasonable performance when you're done,
you'll find that the original Carburetor will work much better.
Most Late-Model-Dirt-Bikes have a very simple Fuel-Injection-System if you're interested,
even some of the larger Lawn-Mower/Industrial, Single, and Twin-Cylinder, Engines are
now coming equipped with crude forms of Fuel-Injection.
A MAP-Sensor won't work very well on a single-cylinder-Engine, ( if that's what you're working on ),
so you'll be limited to what you can make work with just a TPS-Sensor, and a Temperature-Sensor.
And when using only a TPS-Sensor,
it will be very important to provide a rather radical "Accelerator-Pump" function.
The fact that You mentioned "Barometric-Correction", indicates to me that You really
don't have a complete enough understanding of the Fueling requirements of a Gasoline-Engine.
"Barometric-Correction" is only useful for maintaining tight control of the Fuel-Mixture when
radically changing the Altitude that the Engine will be operating in,
such as driving from the bottom, to the top, of a large Mountain-Range, and then back down again.
The Barometric-Changes that occur because of changes in the Local-Weather
are almost completely inconsequential, and may be completely ignored.
You must also have a method for creating 4 separate
"Response-Curves" which will then be mixed together to produce a
total Injector-Pulsewidth in milliseconds,
these factors will be ........
Temperature,
RPM,
Throttle-Position, and
Throttle-Rate-of-Opening.
If You think You can pull this off using 555-Timers, I want to see it,
that would be a really unique Circuit.
A Fuel-Injection-Computer can certainly be done fully Analog,
and can be designed and Tuned to work surprisingly well,
but I can't think of a single reason to use a 555 in this project,
and I think the requirements are much more complex than You may realize.
.
.
.
this is the only reason that there is any reason to even consider the 555 as any part
of a Fuel-Injection/Ignition-Control-System.
If You are simply "wanting to see if You can make it run", more power to ya,
but if You expect the Engine to provide reasonable performance when you're done,
you'll find that the original Carburetor will work much better.
Most Late-Model-Dirt-Bikes have a very simple Fuel-Injection-System if you're interested,
even some of the larger Lawn-Mower/Industrial, Single, and Twin-Cylinder, Engines are
now coming equipped with crude forms of Fuel-Injection.
A MAP-Sensor won't work very well on a single-cylinder-Engine, ( if that's what you're working on ),
so you'll be limited to what you can make work with just a TPS-Sensor, and a Temperature-Sensor.
And when using only a TPS-Sensor,
it will be very important to provide a rather radical "Accelerator-Pump" function.
The fact that You mentioned "Barometric-Correction", indicates to me that You really
don't have a complete enough understanding of the Fueling requirements of a Gasoline-Engine.
"Barometric-Correction" is only useful for maintaining tight control of the Fuel-Mixture when
radically changing the Altitude that the Engine will be operating in,
such as driving from the bottom, to the top, of a large Mountain-Range, and then back down again.
The Barometric-Changes that occur because of changes in the Local-Weather
are almost completely inconsequential, and may be completely ignored.
You must also have a method for creating 4 separate
"Response-Curves" which will then be mixed together to produce a
total Injector-Pulsewidth in milliseconds,
these factors will be ........
Temperature,
RPM,
Throttle-Position, and
Throttle-Rate-of-Opening.
If You think You can pull this off using 555-Timers, I want to see it,
that would be a really unique Circuit.
A Fuel-Injection-Computer can certainly be done fully Analog,
and can be designed and Tuned to work surprisingly well,
but I can't think of a single reason to use a 555 in this project,
and I think the requirements are much more complex than You may realize.
.
.
.