Precision Turbo and Engine BigStuff3 GEN3 PRO SEFI System Hardware & BigComm Software - Manual (Page 29)

BigStuff3 Pro SEFI System
Version 2.1 – February 2011 24
2-Step (Yellow wire)
The 2-step function is not a standard feature on the GEN3 distributor ignition based systems, but the
yellow 2-Step wire can be hooked to enable starting line timing retard for stick shift cars and turbo
applications. The 2-step and 3-step functionality are available as options on the GEN3 distributor
ignition based systems. The 2-Step and 3-Step upgrade must be ordered along with part number
BS3-005-025.
Note: The 2-step functionality is a base feature on all coil-on-plug systems. 3-step control is an option
on all GEN3 systems.
.
If the system is fitted with the BS3 2-step control, the GEN3 ECU will maintain the engine RPM at the
user defined 2-Step RPM limit if the following criteria are met:
 The DAI (or optional DAE) trigger switch is turned on (12V is applied to the data log trigger
wire).
 12V is applied to the yellow 2-step wire (via a clutch, foot-brake or trans-brake switch
 The Throttle position (TPS) is above 25%. The 25% throttle position must be achieved with
a quick tip-in, rather than creeping up to 25% TPS level.
If the GEN3 system was ordered (or upgraded) with the optional 3-step, a second wire will be supplied
in header 2, terminal location W1. This wire must have 12V supplied to it for the 3-step to work.
For the optional 3-step to function correctly, the following criteria must be met.
 12V must be applied to the DAE wire (Hdr 2, wire Y2)
 The Throttle position (TPS) must be above 25%. The 25% throttle position must be
achieved with a quick tip-in rather than creeping up to 25% TPS.
 12V must be applied to the 2-step wire (Hdr 1, wire B2).
 12V must be applied to the 3-step wire (Hdr 2, wire W1). The 3-step function will
automatically override the two step function when 12V is applied to the 3-step wire (with
12V still applied to the 2-step wire).
Note: If the GEN3 system has both 2-step and 3-step functionality, and only one of the two rev starting
line rev limiters will be used, BigStuff3 recommends using the 3-step (two-step high) control.
Note:
The internal (or optional external) data logger trigger wire (describe in the Boost section
below) must be enabled (12V supplied to the data trigger wire) for the 2-step and/or 3-step to
function.
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