Data logging refers to recording the conditions of a running engine. It normally happens using serial communication with the ECU

There are two way for Data Logging:

1. Data Logging through stock DLC Data Link Connector. For more information, see DLC communication

2. Data Logging using ECUs inside serial connector (CN2/CN3) with a modified serial handler of ECU code

For more information on the serial port of an OBD1 ECU, see OBD1 CN2.

For more information on OBD0 ECU serial ports, see OBD0 CN3

Stock OBD1 and OBD0 ECUs have datalogging capability built-in as part of the standard on-board diagnostics OBD. However, the serial port operates at a baudrate of 38400 bps which is not standard for PC serial ports. PCs may be capable of using it, but most of us who do OBD1 datalogging use code based off of Doc's original datalogging code (which contained a bug).

Below are several programs members have written for datalogging with ROMs using doc's modified serial handler.

• ECUControl - The original PGMFI datalogging software, now expanded to cover both OBD0 & OBD1 on Windows (by Nicolas Mailloux?), Palm OS? (by Frederic Maheu?) , and soon Pocket PC?.
• Cuddle - John Cui?'s OBD1 datalogging and RTP control software.
• Turbo Edit - Jason Parker?'s OBD0 datalogging and off-line auto-tuning software.

If the outboard hardware does not support 5v TTL communication, a Serial Adapter will be needed.

JDM P30 ECU's J12 = J4 (may apply to other JDM ecu's, Not sure)-- badboypolar - 24 Mar 2004

Newer notebook computers have USB ports, but no serial ports. Here are detailed instructions on how to integrate a USBMOD3 datalogging circuit into your ECU. -- markolson - 29 Oct 2004

I've documented a how-to on Debugging Data Logging based on the debugging of the datalogging circuit in a JDM P30-901 ECU. -- markolson - 01 Jan 2005

Thanks to taphonomist for finding a good site documenting USB to serial adapter cables. Check out http://pinouts.ru/. Here's the pinout for popular Nokia phones: http://pinouts.ru/data/nokia_pop_pinout.shtml -- markolson - 05 Feb 2005

Nokia cable for datalogging

• Jim Truett's writeup is a pretty good overview of what is required to get a USB Nokia cable working with datalogging. See Nokia Cable Datalogging -- blundar - 28 Mar 2005

• How To Make Nokia Data logging Cable -- wurzel - 18 Feb 2014

Full Duplex Datalogging

• Here is an explanation of Full Duplex Datalogging -- markolson - 24 Oct 2005

How Does Data Logging Work -- markolson - 24 Oct 2005

How To Log External Data Such As An Egt Sensor -- markolson - 24 Oct 2005