Precision Turbo and Engine BigStuff3 GEN3 PRO SEFI (LS1) System Hardware & BigComm Software - Manual (Page 7)

BigStuff3 Pro SEFI System (LS1)
Version 1.0 6
4. Main Wire Harness Installation
To improve the overall wire harness installation process, the harness was manufactured with
identification labels at the end of each wire or connector to ensure that connections are
terminated correctly. The main wire harness has two halves; one half is intended to be located
inside the vehicle, with the ECU, the other half connects to the sensors in the engine
compartment. The two halves of the harness are
separated by a firewall grommet (see photo) designed to
fit snuggly in a 2-1/8” hole, which needs to be located
in the firewall.
The best location for the firewall hole is in an
unobstructed location, on either side of the engine
closest to where the ECU will be mounted in the
passenger compartment. Care should be taken to keep
the harness as close to the center of the vehicle as
possible. Locating the hole to far away from the vehicle center may affect wire lengths, which
need to connect to sensors on the engine. Once the main harness is installed the connections
need to be made to sensors, the ECU, etc. The paragraphs below describe how and where each
connection should be made.
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 for further details.
Firewall grommet