Diagnosing engine problems on older vehicles can sometimes feel like navigating a maze. One user ran into a frustrating issue while trying to use an OBD2 tuner on their 1994 Chevy 4.3 TBI pickup. Despite experiencing classic symptoms like intermittent stalling and rough running, no diagnostic codes were being thrown. This is where an OBD2 tuner should be invaluable, but getting it to connect proved to be a significant hurdle.
The initial approach was logical: suspecting an EGR valve issue, a known good spare was swapped in. Unfortunately, this didn’t resolve the problem. To get a clearer picture of what was happening under the hood, the user opted for a data-driven approach, ordering an ALDL cable from OBD Diagnostics and downloading Tunerpro software. The goal was simple – to read live data and pinpoint the fault without resorting to guesswork and replacing parts unnecessarily.
However, the seemingly straightforward task of connecting the Chevy Obd2 Tuner turned into a troubleshooting saga. While the FTDI drivers and device manager confirmed the USB Serial Converter and Virtual COM port were loading correctly, Tunerpro refused to recognize the cable. Even a direct COM port connection test using Hyperterminal and Realterm yielded no data, indicating a communication breakdown right at the connection point.
Extensive online research led to trying various FTDI driver versions, including 2.08.14, 2.10, and 2.12, but none established a connection. Despite concerns about FTDI driver version 2.10+ potentially causing issues with counterfeit chips, the USB PID flag suggested a genuine FTDI chip in the OBD cable. Regardless, the “cable not found or not functioning” error persisted in Tunerpro across all driver versions and COM port configurations.
To eliminate software or laptop-specific issues, the user tested the setup on three different laptops (two Windows 7, one Windows 10) with identical negative results. Multiple ADX files, including those specifically for the $0D mask expected for this truck, were also tried, but connection remained elusive. The presence or absence of a 10K resistor in the circuit made no difference either.
Direct connection attempts using RealTerm and Hyperterminal, set to 9600/8/N/1, while connected to the vehicle also failed to show any data activity with the key in the ‘on’ position. At this point, the user is understandably running out of ideas. The next diagnostic step involves using a USB OTG cable to connect the OBD Diagnostics cable to an Android phone and try ALDL Droid, further isolating potential driver-related problems on Windows. If the cable remains unresponsive on a different platform, ordering a replacement cable seems like the next logical step.
For anyone who has encountered similar Chevy OBD2 tuner connection issues, any suggestions or insights would be greatly appreciated. Troubleshooting these older systems can be challenging, and community expertise is often the key to finding a solution.
