Precision Turbo and Engine BigStuff3 GEN3 PRO SEFI System Hardware & BigComm Software - Manual (Page 8)

BigStuff3 Pro SEFI System
Version 2.1 – February 2011 8
The instructions below are specific to the BigStuff engine management systems. Hyperlinks
(underlined, blue wording) in the column titled “Further Details” were included to further assist with
the main wire harness installation. Left clicking the PC’s mouse on the hyperlink will immediately
link to a photo of the connector along with additional installation information. To return to the same
location in the table, simply left click on the “Return-to” hyperlink at the end of the text.
Note: Additional components such as relays and special connectors may be required to complete your
specific installation. Contact your dealer or BigStuff3 for further details.
Important System Wiring/Grounding Notes:
BigStuff3 cannot stress the importance of properly grounding the GEN3 system!! The GEN3 main
wire harness ground cables, and the ignition system ground cable(s), MUST BOTH be
grounded to the same negative post, of the same battery!! Failure to run the ground cables from
both of these systems directly to the battery will cause performance issues and potentially damage
one or both of the electronic systems. No other ground paths/solutions are acceptable!
A common practice is to run a AWG 1 through AWG 4 isolated ground from the battery to a firewall
ground lug, and then run every other electrical system ground to it. This grounding solution will create
ground loop issues!! If the isolated ground lug is only going to be used for the GEN3 and ignition
system, then it will work. The problem with this approach is that with time other systems also end up
being grounded to this lug, which will then cause ground loop issues. To avoid ground loop issues,
and the hours of frustration that come with them, ground the BS3 and MSD systems directly to the
battery!!
Also, do not splice any other ground wires (from other systems/components) into either the MSD or
BS3 ground cables.
The GEN3 system 12V power cables can be connected to the vehicle cut-off switch. Power for the
BigStuff3 GEN3 system and the ignition system should also be from the same source (the battery or
the cutoff switch). To avoid the potential of severely damaging the ECU, make the positive and
negative connections to the
battery first, and then connect the header connectors to the ECU.
For coil-on-plug systems, the main wire harness “coil ground” wire (eyelet) must also be grounded to
the cylinder head/engine. No other ground locations are adequate.
If a 16V charging system is being used,
do not charge the battery with the ignition switch on . The
16V battery charger can reach peak voltages above the maximum rated voltage of some of the
electronic circuitry. These over-voltage conditions can completely damage the ECU. This type of
damage is easy to identify and is not covered under the factory warranty!
Also, when running a 16V
charging system with a GEN3 coil-on-plug system, the maximum coil dwell cannot exceed 4
milliseconds. If running a 12V system, the maximum coil dwell cannot exceed 6 milliseconds
.