AEM 30-6821 Series 2 Plug Play EMS Installation Instructions

WARNING:

!

This installation is not for the tuning novice nor the PC illiterate!
Use this system with EXTREME caution! The AEM EMS System
allows for total flexibility in engine tuning. Misuse of this
product can destroy your engine! If you are not well versed in
engine dynamics and the tuning of management systems or are
not PC literate, please do not attempt the installation. Refer the
installation to a AEM trained tuning shop or call 800-423-0046
for technical assistance. You should also visit the AEM EMS
Tech Forum at http://www.aempower.com

NOTE: AEM holds no responsibility for any engine damage that
results from the misuse of this product!

Vehicle fitment

Series I EMS

Series II EMS

2004 Subaru WRX STI

30-1820

30-6820

2005-2006 Subaru WRX STI

30-1821

30-6821

Installation Instructions for:

EMS P/N 30-6820

2004 Subaru WRX STI (USDM 2.5L turbo)

and

EMS P/N 30-6821

2005-2006 Subaru WRX STI (USDM 2.5L turbo)

This product is legal in California for racing vehicles only and should never be used

on public highways.

 2011 Advanced Engine Management, Inc.

ADVANCED ENGINE MANAGEMENT INC.

2205 126th Street Unit A Hawthorne, CA. 90250

Phone: [phone] Fax: [phone]

http://www.aemelectronics.com

Instruction Part Number: 10-6820

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Thank you for purchasing an AEM Engine Management System.
The AEM Engine Management System (EMS) is the result of extensive development on a

wide variety of cars. Each system is engineered for each particular application. The AEM
EMS differs from all others in several ways. The EMS is a stand alone system, which
completely replaces the factory ECU and features unique Plug and Play Technology, which
means that each system is configured especially for your make and model of car without any
jumper harnesses. There is no need to modify your factory wiring harness and in most cases
your car may be returned to stock in a matter of minutes.

For stock and slightly modified vehicles, the supplied startup calibrations are configured to
work with OEM sensors, providing a solid starting point for beginner tuning. For more heavily
modified cars, the EMS can be reconfigured to utilize aftermarket sensors and has many
spare inputs and outputs allowing the elimination of add-on rev-limiters, boost controllers,
nitrous controllers, fuel computers, etc. It also includes a configurable onboard 1MB data
logger that can record any 16 EMS parameters at up to 250 samples per second. Every
EMS comes with all functions installed and activated; there is no need to purchase options or
upgrades to unlock the full potential of your unit.

The installation of the AEM EMS on the supported vehicles uses the stock sensors and
actuators. After installing the AEMTuner software, the startup calibration will be saved to the
following folder on your PC:
C:\Program Files\AEM\AEMTuner\Calibrations\AEM Updates\Subaru\
Multiple calibrations may be supplied for each EMS; additional details of the test vehicle
used to generate each calibration can be found in the Calibration Notes section for that file.

Please visit the AEM Performance Electronics Forum at http://www.aemelectronics.com and
register. We always post the most current strategy release, PC Software and startup
calibrations online. On the forum, you can find and share many helpful hints/tips to make
your EMS perform its best.

TUNING NOTES AND WARNING:
While the supplied startup calibration may be a good starting point and can save
considerable time and money, it will not replace the need to tune the EMS for your specific
application. AEM startup calibrations are not intended to be driven aggressively before
tuning. We strongly recommend that every EMS be tuned by someone who is already
familiar with the AEM software and has successfully tuned vehicles using an AEM EMS.
Most people make mistakes as part of the learning process; be warned that using your
vehicle as a learning platform can damage your engine, your vehicle, and your EMS.

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Read and understand these instructions BEFORE attempting to install this product.

Subaru 2004 / 2005-2006 Model Year Differences

Although there are very few differences between the 2004 and 2005-2006 models, the ECUs
are not interchangeable. The 30-1820 EMS must be used in a 2004 vehicle, and the 30-1821
EMS must be used in 2005-2006 vehicles. Consult the pinout chart for further information.

Peak and Hold Injector Drivers

Injectors 1-4 include Peak (4 amps) and Hold (1 amp) injector drivers. These drivers may be
used with peak and hold or saturated type injectors. The vehicle’s wiring harness may
contain a resistor pack to prevent excessive current if low-impedance injectors were used
with the stock ECU. With the 30-6820 installed, users can elect to remove and bypass
injector resistors for more precise control of low-impedance injectors.

Please note that the injector response time will be different with and without injector resistors
installed. If a resistor pack has been removed and bypassed, please use the correct battery
offset wizard for your injectors. Most battery offset wizards will specify <P&H DRIVER> if
they are intended for use without a resistor pack.

Fuel Pump Control

As supplied from Subaru, the OEM ECU interfaces with a fuel pump control unit (FPCU) to
control the speed, high or low, of the fuel pump based on load. The AEM EMS has the ability
to replicate this functionality; however it is configured in the Startup Calibration to run the fuel
pump at high speed at all times.

The EMS Output COIL8 (Pin B26 for 2004 models, pin B27 for 2005-2006 models) is used to
send a 5V signal instructing the OEM fuel pump ECU to energize the fuel pump. Configuring
User PW Out to use LS12 and, for example, User PW Analog In to MAP Volts will allow the
voltage sent to the fuel pump ECU to be varied in relation to MAP Volts/pressure. Increasing
the duty cycle of the LS12 output will decrease the speed of the fuel pump.

WARNING: Reducing the voltage sent to the fuel pump can affect fuel pump output (volume
and/or pressure). If you wish to decrease pump speed at light loads or low RPM, monitor
fuel pressure and air-fuel ratio very carefully to avoid engine damage!

WARNING: Do not use pin B26/B27 to control a fuel pump relay directly, it must be
connected to the OEM fuel pump control unit only. If an aftermarket fuel pump relay will be
installed, wire it to be controlled using a spare low side output (for instance, LS2 is available
on pin A13). Be sure to configure the output to use the Fuel Pump function using
Tools>>Configure Outputs.

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Variable Valve Control (VVC)
The Variable Valve Control table in the EMS can be used to control the STI’s AVCS system,
which is used to change the airflow characteristics of the engine by advancing the timing of
the intake camshafts. The AVCS outputs (pin A28-A29, Injector 9-10 outputs on the EMS)
advance the phase angle of the intake camshafts; this will have effects similar to moving an
adjustable intake cam gear. This is controlled by the VVC 1 (RH camshaft) and VVC 1B (LH
camshaft) outputs; VVC position is monitored using the T2 and T3 inputs for independent
closed-loop feedback. The VVC settings can be adjusted in the VVC tab (which may be
hidden in the default AEM workspace).

This system is active on this EMS when used with the provided startup calibrations and can

be adjusted through the use of the ‘VVC 1 Target’ map. Adjustments to the intake cam timing

are made by changing the values in the ‘VVC 1 Target’ map per Engine RPM and Engine
Load. The values in the ‘VVC 1 Target’ map can vary from 0 degrees for zero intake cam

advance to 50 degrees for full intake cam advance. The channels ‘VVC 1 Advance’ and
‘VVC 1B Advance’ show the measured position of the camshafts.

WARNING: Improper use of the Variable Valve Control (VVC) in the AEMTuner software can
lead to engine damage!

Be very careful when building or tuning unknown engine combinations or using aftermarket
pistons or valve train components. OEM engines and valve trains are not designed or
manufactured to allow valve to piston interference at certain cam angles. AEM will not be
responsible for engine damage resulting from improper use of the VVC function on engines
with valve trains designed to allow mechanical interference.

Please note that some Subaru camshaft sensors will send ‘false signals’ under some

conditions (often light load and low RPM). This can be observed with an oscilloscope or
high-speed datalogger, and occurs with the stock ECU as well. These false signals will not
cause engine misfires with the Series 2 EMS, but will sometimes be reflected as quick jumps
in the measured ‘VVC 1 Advance’ channels.

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EMS DC Stepper Motor control (Subaru Tumble Generator Valves)

There are two sets of Tumble Generator Valves (TGV) found on the intake manifold of the
STI. Each set of valves is driven by a DC stepper motor and has a 0-5V feedback signal to
monitor valve position. The Motor 1 and Motor 2 Target tables are used to set the position of
the valves; valve position can be controlled based on various parameters such as throttle
position, vehicle speed, engine RPM, or engine load. The channels “ADCR11” and
“ADCR14” display the current position of the valves. When these parameters are near 0
Volts, the valves are open and will allow maximum air flow. When these parameters are near
5 Volts, the valves are closed creating turbulence in the intake stream and restricting air flow.
The valves are always open in the AEM-supplied startup calibrations.

WARNING: the EMS can be configured to control the left and right bank independently. The
engine will run very poorly if one set of TGVs is fully open while the other set is fully closed,
so please be sure that the Motor 1 and Motor 2 Target tables are both the same.

Subaru MAF sensor, Intake Air Temp sensor

The MAF (mass air flow) sensor can be removed to help decrease intake air restriction as
the base map uses the factory MAP sensor to determine engine load. Please be aware that
the IAT (intake air temperature) sensor is integrated into the factory MAF sensor. If the
factory MAF / IAT sensor is removed, you may wish to install an AEM IAT Sensor Kit (P/N
30-2010), which includes a sensor, wire connector, and aluminum weld-in bung. While the
factory MAF sensor locates the IAT sensor upstream of the turbocharger inlet, it may be
preferable to install an IAT sensor downstream of the intercooler to accurately measure
charge temperatures.

EMS Fuel Map, Boost Fuel Trim Table

The 30-6820 calibration maps provided utilize the “Boost Fuel Trim Table” to provide a 1:1
fuel compensation above and below atmospheric pressure. To use this table, the “Boost Fuel
Trim Table” should be configured to provide twice as much fuel when the manifold pressure
is twice as high and half the fuel when the manifold pressure is half as high; this should help
simplify the tuning process for different vacuum and boost levels. Notice the values in the
main “Fuel Map” do not change significantly above 100 kPa (0 psi boost), the fuel correction
is being made by the “Boost Fuel Trim Table.”
Note: the “Boost Fuel Trim Table” must be adjusted if a different MAP sensor is installed or if
the Load breakpoints are adjusted. The Boost Fuel Trim value should be set to -90 at 10kPa,
0 at 100 kPa, +100 at 200 kPa, +200 at 300 kPa, etc…

Check Engine Light

The Low Side 10 output (LS10) activates the Check Engine Light on the gauge cluster. It is
configured to activate at low RPM in the AEM startup calibrations; this can be reconfigured
by selecting Tools>>Configure Outputs.

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AEM Electronic Throttle Control System (ETC)

Figure 1 - Minimum Pedal to Bracket Clearance

The 30-6820 EMS incorporates an ETC system which controls the OEM electronic throttle body. All
components of this system, unmodified and as delivered from the manufacturer, are required for optimum and
safe functionality of this system. These components include, but are not limited to, wiring, ETC relay,
accelerator pedal assembly, and throttle body.

The EMS ETC control system incorporates multiple failsafe strategies such that in the event of a component
failure, the system will shut down the ETC system and, if necessary, the engine in a graceful manner. It still
remains the user’s responsibility to ensure that all vehicle, component, and wiring systems are maintained to a
level of workmanship consistent with industry standards.
Note: As the EMS is intended for use on vehicles that are to be operated off-road only, the factory cruise
control system will be non-operational after installation of the EMS.

Installation Information

The 30-6820 AEM EMS was designed to work with the vehicle, its components, and wiring as delivered from
the manufacturer. If any of the components or wiring have been changed or if the drive-line from the original
vehicle has been placed in another vehicle such in a custom race application then the user should take heed of
the following notes.

A mechanical Wide Open Throttle/”WOT” accelerator pedal travel stop is installed in the floor and/or carpet of
the vehicle as delivered from the manufacturer. If this stop is removed for any reason, such as removing the
carpet for use in a race vehicle, the user must ensure that a stop of some sort is fabricated and installed. This
stop must be fabricated such that there is a minimum clearance of 0.250 inches between the accelerator pedal
mounting bracket and the accelerator pedal actuating rod when the pedal is at WOT. See Figure 1.

The CRUISE and SET/COAST buttons, and the CRUISE and SET dashboard indicator lights are an integral
part of the ETC system calibration and diagnostic functions. It is, therefore, not recommended that these
buttons and lights be completely removed from the vehicle such as could be the case with a purpose-built race
vehicle. If the OEM steering wheel and/or gauge cluster have been removed, please temporarily re-install them
to calibrate the ETC unit, or add switches and lights to the vehicle as shown:

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Electronic Throttle Control System Calibration Procedure

Figure 2 - “CRUISE” and “SET/COAST” buttons

Figure 3 -“CRUISE” and “SET” indicator lights

Figure 4 – Pressing the “CRUISE” button

The 30-6820 / 30-6821 EMS, as delivered, requires a specific calibration procedure to be performed prior to
use. Before beginning this procedure, please be familiar with the location and function of the CRUISE and
SET/COAST buttons on the Cruise Control Steering Column Stalk as depicted in Figure 2. Also be aware of
the (green) CRUISE and SET indicator lights on the dashboard, Figure 3. This procedure should be

repeated any time any part of the ETC system has been serviced, removed, or replaced.

Note: Do not attempt to start or run the engine during the calibration procedure. The EMS will disable engine
start/running whilst in calibration mode.

1. Initial Calibration Procedure

a. Turn the ignition key to the ON position. The CRUISE and SET indicator lights will begin flashing in

unison at a medium rate.

b. Press and hold the CRUISE button (See Figure 4) for approximately three (3) seconds until the

indicator lights stop flashing.
c. There will be a brief delay after which the CRUISE light will flash once.
d. Ensure the accelerator pedal is not being depressed and is in the full “UP” position.
e. The SET indicator light will flash rapidly for a few seconds as the EMS calibrates this position.
f. There will be a brief delay after which the CRUISE light will flash twice.
g. Depress and hold the accelerator pedal to the floor and ensure it is in the full Wide Open

Throttle/“WOT” position.
h. The SET indicator light will flash rapidly for a few seconds as the EMS calibrates this position.
i. There will be a brief delay after which the CRUISE light will flash three times.
j. The SET indicator light will flash rapidly for several seconds as the EMS calibrates the ETC throttle

body.
k. If the calibration procedure was successful and all the ETC sensors and actuators are found to be

within tolerance then the CRUISE and SET indicator lights will flash in unison at a medium rate.
l. If the calibration procedure fails, indicated by the CRUISE and SET indicator lights flashing in an

alternating pattern, please reference the sections entitled ETC Diagnostics and Calibration

Troubleshooting elsewhere in this document.
m. Turn the ignition key to the OFF position.
n. The ETC system is now calibrated and ready for use.

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