Overview, Important application notes – AEM 30-3903 Infinity Plug & Play Harnesses - Volkswagen 2002-2005 MKIV Golf/Jetta 1.8T User Manual

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3903-MKIV 1.8T

Overview

The 30-3903 AEM Infinity Adapter kit was designed for 2002-2005 Volkswagen 1.8T Golf/Jetta/GTI cars with AWP
engine code and manual transmission. This is a true standalone system that eliminates the use of the factory
ECU. The kit is “plug and play” so no cutting or splicing is necessary. The base configuration files available for the
Infinity ECU are starting points only and will need to be modified for your specific application. Please read this
document in its entirety before attempting to start or run an engine.

The available AEM Infinity EMS part numbers for this adapter kit are:

30-7106 Infinity-6
30-7108 Infinity-8h**

Suggested additional components:

30-3903-00 Boost-to-MAP Sensor Adapter Harness
30-2130-50 Stainless Steel 3.5Bar MAP Sensor

Important Application Notes

The test vehicle used for development of this app was a 2003 GTI that was mostly stock except for an AEM cold
air intake and 3" cat-less downpipe. The AWP engine does have variable valve control (VVC) on the intake cam
only that appears to only be utilized during cold starts when the secondary air injection pump is active. The
adapter in this kit has been built to give the Infinity cam control, however the base session does not have any VVC
controls configured as advancing the intake cam during dyno testing showed that power was always decreased.
The stock ECU uses mass air flow (MAF) fueling control using a MAF sensor in the intake piping ahead of the
turbo. The Infinity only uses Speed Density fueling control for this application and the MAF sensor is not utilized in
the adapter so the sensor can be removed if desired. The stock ECU references a boost sensor that is located in
the stock side-mount intercooler ahead of the throttle body. Because the Infinity only uses Speed Density fueling
control, a manifold absolute pressure (MAP) sensor input is necessary that is referencing manifold pressure after
the throttle blade. There is an available boost-to-MAP sensor adapter harness available (AEM part number 30-
3903-00) that allows an AEM stainless steel MAP sensor (3.5Bar MAP sensor suggested, PN 30-2130-50) to be
plugged into the stock boost sensor connector making for seamless integration. See MAP sensor installation
instruction further in this manual.

The stock drive-by-wire (DBW) throttle body has been fully characterized and the provided base session is
configured for its use. Larger throttle size DBW throttle bodies may be used however use of those throttle bodies
will require full characterization and PID controls tuning. None of the stock emissions controls (secondary air
injection, EGR, Evap, etc) are supported. Additionally, the N249 bypass valve activation solenoid is also not
supported. The AWP uses a Bosch wideband O2 sensor from the factory which is utilized by the Infinity through
the cars wiring harness thus an additional O2 sensor is not required. Note that the O2 sensor isn't powered by the
car until the engine is running. Cruise control is not supported by the Infinity and the steering wheel cruise control
buttons are not utilized in any way. The cars CAN datastream is supported by the Infinity and allows for the
factory gauges to function correctly as well as the Infinity to reference all four wheel speeds as well as steering
angle.