ALDLdroid User Manual

ALDLdroid is an Android application that turns your phone or tablet into a full-featured diagnostic, data logging, and tuning tool for OBD-I GM (ALDL) Engine Control Modules (ECMs). Originally built for General Motors vehicles from the mid-1980s through mid-1990s, the app has expanded to support a wide range of vehicles and ECMs from other manufacturers through its flexible, file-based architecture.

ALDLdroid in action — live dashboard, tuning tables, and data log viewer

What is ALDL?

ALDL stands for Assembly Line Diagnostic Link. It is GM's proprietary diagnostic protocol used before the OBD-II standard became mandatory in 1996. ALDL interfaces provide access to the data stream from the ECM, allowing technicians and enthusiasts to read sensor values, trouble codes, and other engine parameters in real time. ALDL typically uses either a 160 baud (older) or 8192 baud (newer) serial communication protocol.

What ALDLdroid Is — and What It Isn't

ALDLdroid is a powerful tool for enthusiasts who are already familiar with their vehicle's ECM and the TunerPro ecosystem. It is not a plug-and-play scan tool like a generic OBD-II reader. You will need the correct ADX (data stream definition) file for your ECM, appropriate hardware to connect, and at least a basic understanding of how your ECM communicates. This manual will help you get there.

This section gets you from zero to reading live data as fast as possible. Detailed coverage of each topic follows in later sections.

Requirements

Installation

First Connection

ALDLdroid communicates with your vehicle's ECM through an adapter that converts the ALDL serial signal to Bluetooth or USB. The app supports both wireless and wired connections, each with its own advantages.

Bluetooth Setup

Bluetooth provides the convenience of a wireless connection. The recommended adapter is the Red Devil River Bluetooth ALDL adapter. The older 1320 Electronics Bluetooth adapter is also fully compatible if you can find one on the used market.

USB (FTDI) Setup

USB connections provide a direct, reliable wired link. ALDLdroid supports any FTDI chip-based USB-to-serial cable. Your Android device must support USB Host mode (also called USB OTG). Most modern Android devices support this, but having a USB port alone does not guarantee USB Host mode compatibility.

Hardware Reference Table

ALDL Protocol Modes

ALDLdroid supports both communication speeds used by GM ALDL ECMs:

Your ADX file determines which protocol mode the app uses. Ensure your ADX file matches your ECM's protocol.

ALDLdroid uses the same file formats as TunerPro, the popular Windows-based ECM tuning software. This means you can share files between the two platforms and leverage the extensive library of definition files available in the TunerPro community.

ADX Files — Data Stream Definitions

ADX files define how ALDLdroid communicates with your ECM and interprets the data stream. Each ADX file is specific to an ECM type and contains the definitions for all readable parameters (sensor data, flags, trouble codes), their memory addresses, and how to decode them.

Selecting a data stream file (ADX) for your ECM

XDF Files — Tuning Definitions

XDF files are tuning definition files that describe the layout of tables, maps, and parameters within a BIN (binary calibration) file. The tuning section of ALDLdroid uses XDF files to present editable tables and allow you to modify calibration data. You can import XDF files directly into the tuning section.

BIN Files — Calibration Data

BIN (binary) files contain the actual calibration data of your ECM — fuel maps, spark tables, idle settings, and hundreds of other parameters. BIN files are opened alongside an XDF definition file so the app knows how to interpret the raw data. You can read a BIN from a chip, modify it using the tuning section, and then burn it back to a chip.

File Management on Your Device

When ALDLdroid runs for the first time, it creates a folder structure on your device's storage:

ALDLdroid/
  ├── adx/          ← Data stream definition files
  ├── xdf/          ← Tuning definition files
  ├── bin/          ← Calibration (binary) files
  └── datalogs/     ← Recorded data log files (CSV and XDL format)

Importing Files

You do not need to manually copy files using a file manager. ALDLdroid provides built-in import functions:

• ADX files — Use the Import data stream function found in the app's Settings section.
• XDF and BIN files — Use the Import file menu located in the Tuning files section of the app.

Where to Find Files

ADX, XDF, and BIN files can be sourced from several places: the TunerPro website, GearHead-EFI forums, ThirdGen.org, pcmhacking.net, TurboTweak, and various vehicle-specific enthusiast communities. Many are freely shared; others may be sold by tuning vendors.

The Dashboard is the primary interface for viewing real-time data from your ECM. It displays live sensor values, flags, and derived parameters using a variety of visual indicator styles that you can fully customize.

Live dashboard with gauges, bar graphs, histograms, and readouts displaying real-time ECM data

Indicators & Display Formats

Each data parameter from your ECM can be displayed using one of several indicator formats:

Edit Mode

To customize your dashboard layout, double-tap anywhere on a dashboard page to enter Edit Mode. In Edit Mode you can:

• Add indicators — Tap the add button and select a parameter from your ADX file, then choose a display format.
• Edit indicators — Tap an existing indicator to change its parameter, format, colors, or styling.
• Delete indicators — Remove unwanted indicators from the layout.
• Drag & reposition — Press and hold an indicator, then drag it to your desired position on the screen.
• Customize colors — Change the color scheme and visual styling of individual indicators.

The dashboard supports multiple pages, so you can create separate screens for different use cases (e.g., one for cruising, one for tuning, one for diagnostics).

Portrait & Landscape Layouts

ALDLdroid maintains separate dashboard layouts for portrait and landscape orientations. Because the screen dimensions change significantly when you rotate your device, each orientation has its own independent arrangement of indicators. You can customize both layouts independently — for example, use a compact stack of readouts in portrait mode for quick glances, and a wider spread of gauges in landscape mode when your device is mounted horizontally in the car. When you rotate your device, ALDLdroid automatically switches to the layout you configured for that orientation.

Dead Indicators

A dead indicator — the parameter no longer exists in the loaded ADX file

If you see an indicator on your dashboard displaying "Dead" with a value of 0 and an X through it, this means the indicator is referencing a parameter that does not exist in your currently loaded ADX file. This typically happens when you switch to a different ADX file (for a different ECM or vehicle) while keeping a dashboard that was built using the previous ADX. The old indicators still reference parameters from the original ADX, and since those parameters don't exist in the new data stream definition, they appear as dead.

Alarms

ALDLdroid can alert you when a parameter exceeds a threshold you define. Alarms are configured per indicator:

• Visual alarm — The indicator turns red when the alarm threshold is exceeded.
• Vibration alarm — Your Android device vibrates when the alarm triggers, useful while driving.

To set an alarm, edit an indicator and enter the alarm threshold value. Common uses include high coolant temperature warnings, knock sensor alerts, or lean/rich O2 voltage limits.

Device Sensors (GPS & Accelerometer)

In addition to ECM data, ALDLdroid can display data from your Android device's built-in sensors:

• GPS — Speed (useful for comparing against the ECM's VSS signal), latitude, longitude, and altitude.
• Accelerometer — Triple-axis acceleration data including calculated G-force. Useful for performance testing and logging lateral/longitudinal forces.

These sensor readings can also be recorded alongside ECM data in your data logs.

The Real-Time Data screen displays a complete, scrollable list of every value and bit mask defined in your currently loaded ADX file. Unlike the Dashboard, which shows only the indicators you have chosen to display, the Real-Time Data view shows everything the ECM is reporting in a simple list format.

Values

Values are numeric parameters from the data stream — things like RPM, coolant temperature, throttle position, spark advance, injector pulse width, MAP sensor reading, vehicle speed, and so on. Each value is displayed with its parameter name and current reading, updated in real time as data arrives from the ECM. The exact list of values depends entirely on the ADX file you have selected, since different ECMs report different parameters.

Bit Masks

Bit masks represent on/off flags and status bits from the ECM. These are typically single-bit or multi-bit fields within the data stream that indicate the state of various engine controls and sensors. Examples include:

• A/C clutch status — Whether the air conditioning compressor is engaged.
• Closed loop / Open loop — Whether the ECM is in closed-loop fuel control.
• Fan relay — Whether the cooling fan relay is commanded on.
• Knock detected — Whether the knock sensor has detected detonation.
• Park/Neutral switch — Transmission gear position indicator.
• Power enrichment — Whether the ECM is commanding extra fuel under heavy load.

Each bit mask is displayed with its name and current state (on/off or true/false), updating in real time alongside the numeric values.

Overview

Tuning section welcome screen

Selecting XDF and BIN tuning files

The Tuning section transforms ALDLdroid into a portable calibration editor. Using TunerPro-compatible XDF definition files paired with BIN calibration files, you can view and modify all the tables, maps, and parameters that control your engine's behavior — fuel delivery, spark timing, idle control, transmission shift points, and much more.

There are two primary tuning workflows:

• Offline editing — Load a BIN file, make changes, save, and later burn the modified file to a chip.
• Real-time tuning — Send changes directly to the ECM's memory via a Moates Ostrich or AutoProm emulator while the engine is running.

2D Table Editing

Most ECM calibration data is organized in one-dimensional or two-dimensional tables (e.g., a spark advance table indexed by RPM and MAP). The tuning editor provides a tabular view of these tables where you can:

• View the full table with row and column headers.
• Select individual cells or ranges of cells.
• Modify values directly by tapping a cell and entering a new value.
• Apply incremental changes across a selection (increase/decrease by a fixed amount or percentage).

2D table view — spark advance map with color-coded cells

3D surface view of the same timing map

Loading Tuning Files

To begin editing, you need to load both an XDF and a BIN file:

Real-Time Tuning

Real-time tuning allows you to push calibration changes directly to the ECM while the engine is running, seeing the effects immediately. This requires a chip emulator installed in your ECM's PROM socket.

Supported Real-Time Tuning Hardware

NVRAM-Based Real-Time Tuning

Some ECMs are equipped with NVRAM (non-volatile RAM) modules that allow real-time tuning without requiring an external emulator like the Ostrich. ALDLdroid supports this feature for compatible ECMs. This has been tested primarily with Australian market ECMs such as the Delco 808.

If your ECM has an NVRAM module installed, ALDLdroid can write tuning changes directly to the NVRAM over the ALDL data link, providing a fully wireless real-time tuning experience when used with a Bluetooth adapter.

Tuning Beyond GM

While ALDLdroid was designed for GM ECMs, the tuning file editor works with any unencrypted XDF/BIN file pair. This means you can use ALDLdroid as a portable BIN editor for vehicles from many other manufacturers, including:

BMW (N54), Buell, DSM (Mitsubishi), Ducati, Ford, Holden, Nissan, Porsche, Volvo, Fiat, Renault, and others — as long as you have the appropriate XDF definition file.

ALDLdroid can write (burn) your modified BIN file to a physical EPROM chip, allowing you to install your custom calibration directly into your ECM. This is the traditional method of applying tuning changes to OBD-I vehicles that use socketed PROM/EPROM chips.

Chip programming screen with addressing settings and action menu (load, erase, verify, program, read)

Required Hardware

Burning a Chip

Data logging records ECM parameters over time so you can analyze engine behavior after the fact. ALDLdroid records all parameters defined in your ADX file plus optional device sensor data (GPS, accelerometer) into CSV and XDL log files for easy export and analysis.

Recording Logs

While connected to your ECM, tap the Record button to begin logging data. All active parameters from the data stream will be recorded at the polling rate of your connection. Tap Stop to end the recording. Log files are saved in CSV and XDL format to the ALDLdroid/datalogs/ directory on your device.

Managing Data Logs

ALDLdroid provides a built-in data log management screen where you can browse, open, rename, delete, and share your recorded log files. All logs stored in the ALDLdroid/datalogs/ directory are listed here with their recording date, duration, and file size.

Available Actions

• Open — Load a log file into one of the built-in log viewers (time-series, scatter graph, or maps) for analysis.
• Rename — Give your log a descriptive name (e.g., "WOT pull highway 3rd gear" or "Idle warm 85F") so you can find it later.
• Delete — Remove log files you no longer need to free up storage space.
• Share / Export — Share log files via email, cloud storage, or any other sharing method available on your Android device. This is useful for sending logs to a tuner or posting them on forums for analysis.

Built-in Log Viewers

ALDLdroid includes three integrated log viewers so you can analyze data without leaving the app. Each viewer is designed for a different type of analysis. You can switch between viewers from the log viewer screen.

Time-series log viewer with RPM, TPS, AFR, and MAP traces overlaid

Time-Series Viewer

The Time-Series Viewer is the primary log analysis tool. It displays parameters as colored line traces plotted against time on the X axis. This is the standard way to review a data log.

Key Features

• Multi-trace overlay — Select multiple columns (parameters) from your log to display simultaneously. Each parameter gets its own color-coded trace, making it easy to see correlations (e.g., RPM rising as TPS increases).
• Cursor / scrubbing — Tap or drag along the timeline to move a cursor that shows the exact values of all displayed parameters at that point in time. This is invaluable for pinpointing the exact moment something happened.
• Zoom and pan — Pinch to zoom into a specific time window for closer analysis, or pan left and right to navigate through the log.
• Column selection — Choose which parameters to display from the full list of logged columns. You can toggle traces on and off to reduce visual clutter.

Typical Usage

Load a data log, select the parameters you want to examine (e.g., RPM, TPS, spark advance, O2 voltage, BLM, integrator), and scrub through the timeline. Look for anomalies like sudden lean spikes in the O2 trace, unexpected timing retard, or sensor values that don't track together the way they should. The overlay format makes it easy to see cause-and-effect relationships between parameters.

Scatter Graph Log Viewer

The Scatter Plot Viewer lets you visualize the relationship between any three parameters from your data log by mapping them to the X axis, Y axis, and color (Z axis). Instead of plotting against time, this viewer shows how two variables relate to each other across your entire log, with a third variable represented by dot color.

How It Works

• X axis — Select a parameter for the horizontal axis (e.g., RPM).
• Y axis — Select a parameter for the vertical axis (e.g., MAP sensor reading in kPa).
• Z axis (color) — Select a third parameter to be represented by the color of each dot (e.g., spark advance, fuel command, or O2 voltage).

Each sample from your data log appears as a single colored dot on the plot. Clusters of dots show where the engine spent the most time, and the color gradient reveals how the Z parameter behaved in those operating regions.

Practical Examples

Maps Log Viewer

The GPS & Map Viewer plots your vehicle's driven path on a map using the GPS data recorded by your Android device during the logging session. The path is drawn as a colored line, where the color represents a selected parameter value at each point along the route.

Key Features

• Color-coded path — The trace on the map is colored according to a parameter you choose (vehicle speed, RPM, TPS, etc.), giving you an instant visual overview of engine behavior along the route.
• Tap for details — Tap any point on the path to see the full set of ECM parameter values at that exact location and time.
• Merge with Time-Series Viewer — The map viewer can be combined with the time-series viewer in a split view. Scrubbing through the time-series chart updates your position on the map, and tapping a point on the map jumps to that moment in the time-series chart.
• Start and end markers — The beginning and end of your route are clearly marked for orientation.

Practical Uses

• Road tuning — Color the path by BLM or integrator to see where on your tuning route the ECM is making the biggest corrections, then focus your tuning efforts on those sections.
• Track analysis — Review speed and RPM through each corner and straight on a track layout. Identify where you are hitting the rev limiter, where shifts occur, and where you are losing speed.
• Diagnosing intermittent problems — If an issue only occurs on a specific hill, curve, or stretch of road, the map viewer lets you correlate physical location with ECM behavior.

Accelerometer Data

When enabled, the app logs your device's triple-axis accelerometer data alongside ECM parameters. This provides G-force measurements for lateral (cornering), longitudinal (acceleration/braking), and vertical forces. The accelerometer data appears as additional columns in your log files and can be displayed in any of the three log viewers.

• In the time-series viewer — Overlay G-force traces against engine parameters to see how acceleration events correlate with throttle inputs, RPM changes, or gear shifts.
• In the scatter plot viewer — Use G-force as an axis to identify how hard you are accelerating at different RPM and throttle positions.
• In the GPS map viewer — Color your path by G-force to visualize braking zones and cornering intensity on a track or road course.

For best results, mount your device securely in a fixed position aligned with your vehicle's axes (screen facing up, top of phone pointing toward the front of the car).

The Settings screen allows you to configure ALDLdroid's behavior and hardware connections.

Settings screen — ECU connection, data stream file, checksum, and sensor logging options

GM OBD-I (Primary Support)

ALDLdroid was built for GM vehicles using the ALDL protocol. This covers a wide range of ECMs found in GM vehicles from approximately 1982 through 1995. Common ECMs include various members of the Delco family: the 1227747, 1227730, 1228746, 16198262, 1227808 (Australian Delco 808), and many others. Compatibility depends on having the correct ADX file for your specific ECM and mask.

Common GM Vehicle Platforms

The app is popular among owners of Chevrolet Camaros and Pontiac Firebirds (Third and Fourth Generation F-bodies), Corvettes (C4), Buick Grand Nationals and Turbo Regals, S-10/S-15 trucks, and various other GM vehicles of the era. If your vehicle has an ALDL connector and a supported ECM, ALDLdroid can likely talk to it with the right ADX file.

Non-GM Vehicles

ALDLdroid is not limited to GM vehicles. ADX definition files exist for a wide range of manufacturers, including BMW, Buell, DSM (Mitsubishi), Ducati, Ford, Holden, Nissan, Porsche, Volvo, Fiat, Renault, and others. With the appropriate ADX file, ALDLdroid can provide live data streaming and diagnostics for these vehicles as well. The tuning editor also works with any XDF/BIN pair for offline calibration editing.

Troubleshooting Tables (Reference)

Cannot Connect to ECM

Data Looks Wrong or Erratic

Tuning / Chip Issues

Official

• ALDLdroid Website — aldldroid.com
• Google Play Store — Search "ALDLdroid" for the latest version
• Developer — Sébastien Giroux

Community Forums

• ThirdGen.org — Active discussion thread for ALDLdroid, especially popular with F-body owners
• pcmhacking.net — Extensive technical discussion spanning 38+ pages of ALDLdroid usage, troubleshooting, and feature requests
• GearHead-EFI — Long-running ALDLdroid thread (70+ pages) with detailed setup guides and user experiences
• TurboTweak / TurboBuick — Resources specific to Buick Grand National and turbo Regal owners
• CorvettefForum — C4 Corvette-specific ALDLdroid discussion

File Resources

• TunerPro — tunerpro.net — Source for ADX and XDF files, plus the desktop companion software
• Moates — moates.net — Manufacturer of the Ostrich, AutoProm, BURN1, and BURN2 hardware

Related Software

• TunerPro RT — The free Windows-based ECM tuning and data logging software that ALDLdroid's file formats are based on
• MegaLogViewer — A powerful cross-platform data log analysis tool that can open ALDLdroid's CSV log files