Haltech F9A - Manual (Page 50)

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The heights of the increase bars and the sustain bars are adjusted using the same keys that are
used for adjusting the fuel curve bars. The left and right arrow keys allow you to move from
one bar to the next.
The throttle pump values should be set up after the fuel and maps are correctly tuned for
steady load running. Attempting to smooth out engine transients before the fuel maps have
been optimised for steady state running may become confusing. The six throttle response bars
should be adjusted by trial and error to give optimum throttle response in each rev range.
Generally, you may not need much above 3000 rpm, but could expect much higher values
below 1500 rpm.
Note that throttle response can also be affected by poor manifold design. If you have designed
your own inlet manifold you may find that although the engine runs well at steady load it
leans out if the throttle is opened suddenly. This will occur if the fuel injectors are poorly
positioned and the fuel is wetting down the walls of the inlet manifold rather than remaining
as a mist.
The final parameter on the Throttle Pump page is the Coolant Factor. Generally, when the
engine is cold, accelerator pump values need to be increased slightly. The F9 therefore applies
a coolant correction to the throttle pump in the same way as it does to the base map.
The Coolant Factor may be set with values from 0 to 4. Setting it to 0 will negate all coolant
correction to the throttle pump. The default setting for this parameter is 0.5.
6.2 Zero Throttle Map
One problem that often occurs with performance engines is rough idling. The manifold
design, cam characteristics, etc. can cause instability in the air flow. This makes fuel metering
difficult. In particular, the Map sensor often can not correctly read the manifold pressure, as it
is either non existent, weak, or pulsing too much. In many cases though, once the engine has
some speed, the manifold pressure signal is useable.
The best method of mapping the engine is using the manifold pressure as the load. If in this
configuration idling is causing a problem, the Zero Throttle Map should be tried. This Map
maps the fuel delivery at zero throttle below 2000 rpm. There are a few requirements that
need to be met before you can use this Map. Firstly, your throttle position sensor must be
calibrated properly. Secondly, the Map relies on there being a consistent air flow at zero
throttle for a given engine speed. That means that devices such as idle speed motors that vary
the air flow at zero throttle will not allow the Zero Throttle Map to operate correctly.