730 Pump Shot

[Heelandtoe at aol.com]

The potential flaw in this theory is that if your regulator has a vacuum 
line, it automatically compensates for MAP changes.  Manifold pressure 
changes caused by rapid throttle openings will be realized at the regulator 
instantaneously, however there may be some small lag in the fuel pressure 
responding.  How large are the changes in pump shot again?
jc



NickG wrote...
 
One thing to consider in the TPI system is that the fuel pressure increases
with lower manifold vacuum. Thus, when you step on the gas a little bit, the
manifold vacuum drops a bit, and the fuel pressure rises a little. When you
go WOT, the greatest change in manifold vacuum occurs, and the fuel pressure
rises to the max setting.

Obviously, more fuel pressure causes more fuel to be sprayed by the
injectors. Maybe that's why the pump shot table has decreasing values as the
%TPS increases. The TBI/'747 setup does not change the fuel pressure
according to manifold vacuum.

Nick
 

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