Two TBI units, one ECM

[Walter Sherwin]

"Synchronous Simultaneous Single Fire" mode, and "Synchronous Simultaneous
Double Fire" mode.  Two different port injection control strategies that can
fire ganged banks of injectors either once per every other crank revolution,
or once per every crank revolution.

By contrast, delayed dual channel TBI control will predominantly fire one of
the two injectors in sync with every other logic reference pulse, and will
fire the other injector in the same fashion but delayed by one reference
pulse period with respect to its mate.   Was done to try to distribute the
wet fuel charge more evenly in the manifold.  This type of control can also
flip/flop back & forth from a synchronous mode (in sync with the reference
pulses) to an asynchronous mode (time based fueling irrespective of the
reference pulses).  The mode flip/flop is used to accommodate the extreme
dynamic flow/BPW requirements at the low end (idle) and at the high end
(high RPM high load).

Walt.




>Thanks Walt,
>was thinking the Sunbird injectors were 4/1 Amp peak&hold..
>This changes things a bunch.
>BTW what is SSSF & SSDF?
>Mike V
>
>> Ummmm..............the "749"  houses two 4/1 Amp peak&hold injector
current
>>  drivers, which were originally intended to drive two individual parallel
>>  sets of 2/.5 Amp peak&hold Rochester port injectors.  This particular
box
>>  was expected to drive the the two pairs of injectors in either SSSF or
SSDF
>>  port fuel mode.  Both electrically, and programatically, this is
entirely
>>  different than what is required for dual channel TBI control, especially
if
>>  you want to run "twin" TBI's.