Haltech E6A - Manual (Page 53)

53
5.5.1 Tuning for Idle
The idle mixture is very sensitive to correct bar height. Idle injection times are usually around
1.5 to 2.5 mS. If the injection time at idle is much lower than this, it may become difficult to
set accurate idle and cruise air:fuel ratios.
If the engine is hunting at idle, then the map is probably too lean, particularly at the 500 rpm
point. Watch the movement of the map arrow carefully. The map arrow should remain stable
while the engine is idling. If the arrow is moving excessively in a MAP based system, then it
may be necessary to use the Zero Throttle Map.
Remember that the E6A interpolates against both rpm and load. If the engine is idling at 800
rpm, then the injection time is computed as 60% of the value from the 1000 rpm range, and
40% of the value from the 500 rpm range, so both ranges would have to be adjusted to get the
correct mixture. Similarly, if the idle mixture is reacting poorly to changes of the bar indicated
by the map pointer, then try adjusting the adjacent bars. Wait for the engine to heat to
operating temperature before performing further changes to maps.
5.5.2 Tuning with No Load
Using the throttle only, increase the engine speed to 1000 rpm. If the engine is at exactly 1000
rpm then only that range needs to be adjusted. Adjust for the crispest engine response. Engines
will usually idle rich, then head towards stoichiometric mixture at higher speeds. Repeat for
1500, 2000, 2500, 3000 etc. The engine should now start and fast-idle evenly. You should also
have the engine running at operating temperature before going further. Go to the Engine Data
Page at this point and check all the sensor inputs are reading correctly, and that the
temperatures have stabilised before continuing.
While free-revving at higher engine speeds, check the Engine Rpm reading on the computer. If
it becomes erratic, or fails to follow the actual engine speed correctly, check the section in
Chapter 1 on setting the trigger. Also make sure that the information in the Identification and
Setups is correct.
5.5.3 Loading the Engine.
Once the engine has been tuned properly for no load conditions it is possible to begin loading
the engine. The best method of applying load to the engine is using a dynamometer. However,
if access to a dyno is not possible the engine can be tuned on the road.