Haltech E6A - Manual (Page 56)

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SECTION TWO
Other Adjustable Features
Chapter 6
Throttle Effects
6.1 Throttle Response
Where the procedures described in the previous chapter tune for constant load running, the
functions outlined in this section will improve the throttle response of your engine.
The manifold pressure sensor used with the E6A is very fast. It can respond much faster than is
required to track any sudden changes in load on your engine. The manifold pressure seen at the
sensor input does not change as quickly, due partly to the length of the connecting pipe. This
can be improved by keeping the length of vacuum hose between the inlet manifold and the
pressure sensor as short as possible. Even with very short vacuum hose lengths there may still
be a lag between a transient pressure occurring and the pressure reaching the sensor.
Further, when the throttle is cracked open, the sudden change in pressure forces fuel out of
atomisation and onto the manifold walls, so it fails to enter the combustion chamber properly
atomised, and the engine hesitates. This can be corrected by adjustment of the Throttle Pump
parameters.
To overcome any lean out during sudden throttle movement, the Haltech system uses a throttle
accelerator pump function. This function delivers extra fuel during sudden throttle movements.
The Throttle Pump is accessed from the Fuel Maps and Setup Menu.
Six single bars will appear on the screen. The two bars on the left are used below 1500 rpm.
The two bars in the middle operate between 1500 and 3000 rpm and the two bars on the right
are used above 3000 rpm. These bars set the amount of extra fuel that will be added to the
current fuel value during a sudden change in throttle. This extra fuel is added progressively as
the throttle movement continues.
The increase bars determine how much extra fuel the engine gets when you open the throttle.
Once the throttle movement stops the extra fuel value decays at a rate set by the sustain bars.
This feature is used to allow the engine to catch up to the transient that has occurred and,
consequently, its value will be dependent on manifold design.