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UltraGauge
Blue
™
User Manual www.ultra-gauge.com
Ignition Timing
Advance
Gauge name
Range
Units
Abbreviation
Timing Advance
-64 to 63.5
degrees
Timing Adv
Ignition timing spark advance in degrees before top dead center for cylinder #1. Does not
include mechanical advance, if any.
EGR Commanded
Gauge name
Range
Units
Abbreviation
EGR % Flow
0 to 100
%
EGR Flow
The percent of flow through the Exhaust Gas Recirculation (EGR) valve, where 0% is closed
and 100% is wide open. This is the commanded value indicating that the Engine Control Unit
(ECU) is requesting the EGR to have the desired flow. The actual flow may be different if there
is an issue with the EGR.
Evaporative Purge
Gauge name
Range
Units
Abbreviation
Evaporative Purge %
0 to 100
%
Evap Purge
Commanded Evaporative Purge percent. A value of 0% is no flow, and a value of 100% is wide
open maximum flow. This is a commanded value indicating that the ECU is requesting the %
flow. The actual flow may not match.
AFR Commanded
ratio
Gauge name
Range
Units
Abbreviation
AFR commanded ratio
0 to 1.999
F/A
F/A Ratio
Fuel Air Commanded ratio. This is the value of Lambda requested by the ECU
= (Stoichiometric F/A ratio) / (Actual F/A ratio) >1 is lean, <1 is rich.
To determine the actual A/F ratio commanded, multiply this value by 14.64
For example. If this value is 0.90, the commanded Air Fuel Ration is 0.90* 14.64 = 13.17 parts
air to one part fuel.
Relative Throttle
Position %
Gauge name
Range
Units
Abbreviation
Rel Throttle Pos %
0 to 100
%
rThrottle
Relative or learned throttle position. A throttle position sensor may never return to its minimum
position, but instead closed throttle may always be greater than the TP Sensor’s absolute
minimum. This throttle position gauge adjusts for this true closed throttle position. When the
throttle is closed, this gauge will read 0% regardless of the details of the absolute throttle
position. The relative position value is calculated as follows:
Relative % = (TP output) – (TP output closed) X 100
(TP output max)
Example: If the output of the TP is 1V when closed and 10 volt when wide open, an output of 5V
would be: (5-1)/10*100 = 40%
Note: This means that this gauge will likely never reach 100%
