Haltech E6K - Manual (Page 51)

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To check the base timing you should now start the engine with the Timing Lock on. The
engine should now start and run although with only Lock Timing Angle° of ignition advance
the idle speed may be lower than usual.
If the engine does not start it may be because the fuel requirements are not right. If this is the
case, it is suggested that you disable the injector output and do the timing check while
cranking. This will require two people : one to crank the engine and one to operate the timing
light. It can be difficult to check the timing accurately at cranking speeds. Removing the spark
plugs will help the engine to rotate at an even speed. Once you have checked the timing at
crank, leave the Timing Lock on, skip the next section on loading an Ignition Library Map
and go to the section on Determining Engine Fuel Needs. Once you have the engine starting
and idling, return to this section, check the timing again, and then load the Library Map.
Use an ignition timing light to check that the ignition timing is set to the angle that you have
entered for Lock Timing Angle °BTDC (a common value is 10
°
BTDC). See the workshop
manual for your engine for details on checking ignition timing and the use of a timing light.
The timing should be locked at Lock Timing Angle° BTDC. If it is not then the angle at
which the ECU is being triggered is not the same as the angle in the Trigger Degrees field in
the Ignition Set-up. If the timing is miles out, go back and check all the angles again. If you
have guessed the trigger angle, try and calculate it properly. Remember that the angle is in
crank degrees, not distributor degrees. Also make sure the trigger edges are correct. These can
have a very large affect on the trigger angle.
If the angle is a little out, it is just a matter of aligning up the actual trigger angle with the
angle in the Trigger Degrees field. There are a few ways to do this :
•
If the timing reference is taken from a distributor, then you may be able to rotate it while
using the timing light until the engine is at Lock Timing Angle ° BTDC. Be wary about
adjusting the base timing in this manner by any more than a few degrees as it can upset
the rotor phasing. For details on rotor phasing, see Appendix F.
•
If the reference is taken from a cam angle sensor (such as in a distributor-less direct fire
engine), then if it is possible, rotate the sensor while using the timing light until the engine
is at Lock Timing Angle° BTDC. With a cam angle sensor, there is no need to worry
about rotor phasing.
•
The last method is to change the Trigger Degrees field in the Ignition Set-up. (See the
previous Chapter for details on how to change this field). If you are using a crank angle
sensor then this is the easiest way to adjust the base timing. The Trigger Degrees field
tells the ECU where the trigger is occurring. Once the ECU receives this trigger, it
calculates how many engine degrees to delay until it has to fire the spark. For example, if
the trigger is at 70° BTDC, and the Timing Lock is on and the timing lock angle is set to
10° BTDC, the ECU will delay 60° and then fire the spark at Lock Timing Angle° BTDC.
If however, the trigger was actually at 80° BTDC, but the Trigger Degrees had a value of
70, the ECU would still delay the 60° and the engine would fire at 20° BTDC. Changing
the value of the Trigger Degrees field to 80 would increase the delay from 60° to 70°, and
the engine would now fire at Lock Timing Angle° BTDC. When adjusting the parameter,
do so in small steps, say 5 or 10 degrees at a time. This will allow you to check that you
are moving in the right direction.