These parameters can be accessed through the pulldown menus by selecting VIEW/SYSTEM CONFIGURATION/OPERATIONAL PARAMETERS.  Click on any of the parameters in the image below to jump directly to information on that topic.

Table Cell Width
This parameter defines the RPM range of a single cell within the base fuel table, the ignition timing table, and the target air/fuel ratio table.  Since these are 16-column tables, the range of RPM control can be figured by multiplying the number entered here by 16.  For example, if you set the cell width to 500 RPM, 500 RPMx16=8000 RPM.  Changing this value will also change the placement of the data within the fuel and spark tables.  Some recalibration of the tables will likely be necessary if this number is changed.

Rev Limit High
This parameter defines the RPM that must be exceeded to enable the rev limiter.  When activated, the rev limiter will prevent the fuel injectors from firing (and turn off the nitrous oxide system, if activated) until the engine RPM drops below the value specified in Rev Limit Low.  In order to work properly, this value must be set higher than the value in Rev Limit Low.

Rev Limit Low
If the rev limiter has been activated, the engine RPM must fall below the value entered here before the fuel injectors will begin firing again.  In order to work properly, this value must be set lower than the value in Rev Limit High.

Engine Revs to Run Mode
This parameter defines the number of crank pulses that must be received while the engine RPM exceeds the value specified in Crank to Run Mode RPM before the ECU switches from “Cranking” mode to “Run” mode.

Crank to Run Mode RPM
This parameter defines the RPM threshold where the ECU will switch from “Cranking” mode to “Run” mode.  In Cranking mode, fuel delivery is based only on the cranking fuel table.  In Run mode, fuel delivery is based upon the values in the base fuel table.  The ECU will switch from Cranking mode to Run mode when it detects the engine operating above the RPM specified here for the number of counts specified in Engine Revs to Run Mode.  

Fuel Pump Prime
If fuel pump control is available, this parameter defines the number of seconds that the fuel pump control output on pin S3 will activate when the ignition is turned on.  3 seconds is typically more than enough time for an electric pump to fill and pressurize the fuel system.

Injector Opening Time
This parameter defines the amount of time that it takes from the instant that an electrical signal is applied to a fuel injector until fuel actually flows from the injector.   This value is added to the base pulsewidth value to compensate for injector opening delays.  Because the base pulsewidth value is always changing and this value is constant, the effects of changing this setting will be most pronounced where the base pulsewidths are smallest - typically at idle and light cruise.  Here is an example.

Let's assume the engine is idling, and the base pulsewidth value is 3.0 milliseconds.  The injector opening time is set to 1.0 millisecond.  These two values will be added together, and the reported pulsewidth will be 4.0 milliseconds.  If you were to increase the injector opening time by 0.5 millisecond, the new reported pulsewidth would be 4.5 milliseconds - a 12.5% increase.

Now let's assume that with this same calibration, the base pulsewidth at full throttle and 5000 RPM is 20.0 milliseconds.  With an injector opening time of 1.0 millisecond, the reported pulsewidth would be 21.0 milliseconds.  Increasing the injector opening time by 0.5 millisecond as in the last example yields a new reported pulsewidth of 21.5 milliseconds - a mere 2.5% increase!

The actual time an injector takes to open will vary slightly as battery voltage fluctuates.  Higher battery voltages will open an injector faster, so the injector opening time will be reduced to compensate for this.  Alternatively, as battery voltage decreases, an injector will be slower to open.  The injector opening time is increased to make up for this.  The opening time will be modified as per the following graph:

Fan On Temp.
If fan control is available, this parameter defines the coolant temperature that must be exceeded to activate the cooling fan control output on pin R3.

Fan Off Temp.
If fan control is available, this parameter defines the temperature that the coolant must go below before the cooling fan control output will turn back off.

Crank Reference Angle
This parameter defines the actual engine position at which the crank sensor signal is received.  In other words, this value should correlate with where the ignition timing is actually set on the motor so that the ECU and the engine have a common reference point.

On inductive pickup ignition systems, the reference angle (as well as the base ignition timing on the motor) is typically set to 50-60 degrees.  The ECU then delays this signal according to the values specified in the ignition timing table.  The advance may be set up to 10 degrees lower than the reference angle; e.g., if your reference angle is set at 50 degrees, you may run up to 40 degrees of advance.  This 10 degree margin is enforced to provide time for the ECU to perform fuel and spark calculations.

Many factory ignition systems have a pre-determined amount of advance “built in” to them.  On systems of this type, timing values entered into the spark table must be at least 0.25 degree higher than the reference angle.  The most common reference angles for factory ignition systems are as follows:

• GM HEI - 6 degrees
• GM Optispark - 6 degrees
• Buick DIS – Ten degrees
• Ford TFI – Ten degrees
• GM Northstar – Ten degrees
• Ford EDIS – Ten degrees

When the crankshaft reference angle is correctly entered, the ignition timing as measured with a timing light should match the value reported by the ECU.  This value can be found at the bottom of the spark table screen in a sensor labeled “Spark (BTDC)”.  If necessary, small changes to the crankshaft reference angle can be made to align the reported timing value with the value measured with a timing light.

Inductive Delay
This parameter is used to compensate for the varying delays that occur with different types of crank sensors.  These varying delays often cause ignition timing error that will increase as engine RPM increases.

For inductive pickup ignition systems, leave this parameter set to 96 uS (microseconds).  For other types of ignition systems, this value can be altered to reduce or eliminate ignition timing error as a function of RPM.  This error will show up as either unwanted timing advance as RPM increases or unwanted timing retard as RPM increases.  Increasing the value in this parameter will reduce unwanted timing retard, and decreasing the value in this parameter will reduce unwanted timing advance.

Speed/Density Mode
When this radio button is selected, the ECU will operate in Speed/Density mode. 

Alpha-N Mode
When this radio button is selected, the ECU will operate in Alpha-N mode.

Click here for information on selecting between Speed/Density mode and Alpha-N mode.