INSTALLATION INSTRUCTIONS
3
Wide-Band 02 Sensor:
A Wide-Band 02 sensor is supplied in the Atomic LS Master Kit. This sensor is
responsible for constantly monitoring the exhaust gases and relaying that information to the ECU where
adjustments are constantly made to the fuel delivery in order to meet the air/fuel targets. Only one sensor
is required. Page 5 outlines the sensor installation.
Crank Sensor:
The LS engine platform has used two different crank position sensors through the years.
There is a 24-tooth wheel or a 58-tooth wheel on the crankshaft. The sensor has always been located
behind the starter. The 24-tooth sensor has a black connector whereas the 58-tooth sensor has a gray
connector. The Master Kits are supplied with connectors for both the 24x and 58x trigger sensors.
Cam Sensor:
The Cam Sensor of LS engines has changed throughout the years. Not only it’s location,
but its wiring as well. Early models have the cam sensor located at the back of the block near the deck
surface. During 2005, as a running change, the location changed to the front of the block between the cam
and crankshaft. The Atomic LS system can function with both designs.
Throttle Body and Sensors:
The Atomic LS requires a mechanically operated throttle body. In the future
Throttle by Wire applications will be covered. The Atomic has all of the OE connections for the throttle
body including Throttle Position (TPS) and Idle Air Control Solenoid (IAC).
Intake Air Temperature (IAT) Sensor:
This sensor is supplied and it is recommended to install it in the
air intake duct before the throttle body. A 3/4" hole is required for the sensor.
Rev Limiter:
There are two settings for a rev limiter; one through fuel, one through ignition. There is an
optional 2-Step Rev Limiter that can be used on the starting line for a low rpm limit. This is temporarily
activated through the Dark Blue wire of the Power Module to produce consistent launch rpm.
Aftermarket Auxiliary Settings:
The Atomic LS system can support aftermarket performance parts or
power adders that carry a CARB Executive Order number. There are accessory controls to properly adjust
the timing and fuel delivery to meet the requirements of these auxiliary components. See the advanced
settings on pages 15-16.
FUEL SYSTEM REQUIREMENTS
The Atomic LS fuel injection system requires a high pressure fuel pump system. The fuel system is
not supplied due the large variety of applications incorporating the LS engine platform. Depending on
your engine combination, the Atomic LS requires a minimum of 58-62 psi to operate. When selecting
a pump, regulator and lines, be sure each component is designed to perform at high pressure. MSD
offers fuel pumps, hose and accessories to complete your installation. Following are some guidelines
in helping set up a fuel system for your Atomic as well as components available separately from MSD.
• The Atomic is capable of operating with a return or returnless style system. For best results with
either system, MSD strongly recommends an in-tank pump. Installing the fuel pump in the tank
results in quieter operation, less chance of cavitation and a reduction in pump temperature.
• When running a returnless fuel system (Pulse Width Modulated) the fuel pump must be mounted
in the tank. It is recommended to use an MSD Atomic Fuel Pump, PN 2925 or PN 2926.
• MSD supplies -6 AN clamp-style fittings for the fuel rails. These fittings must be used with MSD's
high pressure EFI hose. Refer to page 9 for installation.
• If mounting the pump in the tank is not an option, install the pump as close as possible to the tank.
Within 2-feet of sending unit is recommended.
• Do not use hard line when plumbing the fuel system. When using a PWM fuel system, pulsations
and harmonics could cause unstable fuel pressure resulting in pump cavitation or poor engine
performance.
