Haltech F10 - Manual (Page 51)

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CHAPTER 7 COLD STARTING AND RUNNING
The Haltech F10 has features to modify fuel delivery to aid in starting and running a cold
engine. The Cold Start Prime map gives a cold engine an initial burst of fuel just as the
engine begins cranking. The Coolant Correction M ap modifies the normal fuel injection until
the engine reaches normal operating temperatures.
7.1 Cold Cranking
At cold crank the air speed at the inlet manifold is very low. As a result a lot of fuel that
would normally travel in the air, sticks to the manifold walls and doesn't enter the engine. The
cylinder chamber temperatures are also low which leads to poor combustion. To overcome
these inefficiencies, it is necessary to prime the engine with a long pulse of the injectors at the
start of cranking to ensure that the engine has enough fuel in the cylinder to fire. The F10
ECU has a “Fuel Prime M ap” to perform this function.
To access the Fuel Prime M ap press Alt – M to open the M aps menu then scroll to the Fuel
Prime menu item and press enter.
The fuel prime is adjustable at all engine temperatures. This allows the duration of the prime
pulse to be optimised for cranking across all temperatures. The cold prime map specifies an
injection time based on engine coolant temperature. The heights of the bars define the time
that the injectors are open.
Over priming the engine will cause it to flood and not start. To clear a flooded engine, open
the throttle fully and continuously crank the engine. Do not pump the throttle as this will only
worsen the problem.
7.2 Cold Engine Operation
Once started, an engine requires more fuel when it is cold than when it is hot. This is a result
of low manifold and combustion chamber temperatures where fuel sticks to the walls and
doesn't burn properly. The Haltech system corrects for this by using the Fuel Coolant M ap to
supply the extra fuel required at different temperatures. The F10 will automatically reduce
the amount of coolant correction applied to the engine as the throttle is opened and air speed
increases. The Fuel Coolant M ap should not be adjusted until the Fuel M aps are correctly
tuned at operating temperature.
To access the Coolant M ap press Alt – M to open the M aps menu then scroll to the Coolant
M ap menu item and press enter.
Access the Fuel Coolant M ap from the Fuel M aps and Set-up M enu. The map defines the
percentage increase in fuel at any given engine temperature. The F10 is supplied with a
default coolant map which may not need to be modified. Start the cold engine and adjust the
Fuel Coolant M ap so that the engine idles evenly. You should not touch the throttle while
adjusting this map. Follow the arrow as the engine warms to provide good running mixtures
up to operating temperature, where there should be zero coolant correction.