Computer Diagnostics

[Keywords: CSC Cyclone, Motorcycle, OBDC, OBD, Delphi, Fuel Injection, Computer, K-line, K2000]


Under the floor which is under the passenger seat of the Cyclone RX3 is a connector designed to be coupled to a Delphi diagnostic computer which can read a host of operating parameters when the engine is running. THE MT05 EMU (Engine Management Unit) communicates with an external computer via this connector using a K2000 OBDC II (On Board Diagnostic Computer) link.

To read this data you need an appropriate computer running the right diagnostic software (more on that later) but you also need a physical and electrical interface (i.e. a connector cable). Computers don't have OBDC K2000 compatible ports. What most have these days is a USB port, so you need a K2000 to USB converter. In China you can buy a cable that plugs into the RX3 diagnostic socket at one end and into a USB port at the other. However unless you speak Chinese or go through a broker, getting said cable is difficult, takes time and costs around $40. Even going through a broker appears not to be a trivial exercise.

Here's how to get and modify a cable from eBay (assuming you're capable of soldering three wires). First you find what is called a VAG-COM USB cable. This is designed to connect to the OBDC II port of Volkswagen cars. Technically it's a K2000 to USB interface cable. There are two chips inside. One is an LM339 Quad comparator that takes the K2000 serial data and converts it into RS232 (or maybe RS 432?) serial format. The second chip (a CH340T) takes this data and converts it to a USB signal. Note that this cable plugs into a standard car OBDC port, not the RX3 diagnostic connector. What you need to do to make the RX3 connection is open up the cable housing and solder in three wires. One (let's make it red) goes to pin 16 of the OBDC connector and carries the +ve battery voltage. One (let's make it black) goes to pin 4 of the OBDC connector and is the ground connection. The third lead (let's make it yellow) carries the K2000 data and goes to pin 7 or the OBDC connector. You may be able to pick off these signals at the connection between the OBDC connector and the circuit board inside the cable housing as shown below:

The other end of the red, black and yellow wires goes to the RX3 diagnostic connector. I have not yet been able to definitively locate the male plug that mates with this female connector, but it seems to use 2.8mm connector pins. It may be a Furukawa RFW 090 6pin plug but I haven't confirmed that yet. What I did was add the connector pins to the ends of the wires and then just slide the pins into the socket as shown below:

If it's not clear from the image which wires to to which pins of the connector, just look at the color of the wires going into the connector from the wiring harness. The red wire (pin 6) is the +ve battery connection and connects with the new red wire. The green wire (pin 2) is the ground and connects with the new black wire. The white wire with the black stripe (pin 4) is the K-line (K2000) connection and connects with the new yellow wire.

That's the hardware side of things, but there's a little more. The software used to look at the data from the EMU takes its input from a serial port, not a USB port so you need to install a driver that looks like a serial port to the software, but converts the serial commands into a USB signal. This driver should come with the VAG-COM cable on a CD. To install it all you should need to do is plug the cable into a USB port on your computer, put the CD in the CD drive and let windows find the driver when it auto installs the USB to serial hardware.

The Software

The software used to communicate with the EMU is known as PCHUD and was written by Delphi (the maker of the MT05 EMU) back in the dark ages. In fact it's written for Windows 3.1, which means it was probably developed around 1993, over 20 years ago. Luckily it will still run on Windows XP, but it will not run on 64-bit Windows 7 even in compatibility mode. Though I have not tested it myself, it's reported to run OK on 32-bit Windows 7 [UPDATE - I've tested it and I can now confirm that it runs on 32-bit Windows 7]. Where to find PCHUD is your next problem. There are sites in China and Russia which have copies. The best pointer I can give you is a link to a thread on the ChinaRiders forum - That post also shows the cable which is available in China.

The software requires the use of a serial port in the COM1 to COM4 range. When you install the USB to serial driver it will find the first COM port it thinks is available. However Windows doesn't keep track of COM ports very well. It opens them but often doesn't mark them as closed, so you may find it's installed your USB to serial connection on COM ports above COM4, say COM9. In that case you'll need to reassign the port. You can find out how to do this here -

The instructions for running PCHUD can be found in the Dephi Small Engine Management System Service Manual as well as in the links in the Chinariders forum. There's also a powerpoint presentation you can download.

Once you have it configured correctly, as outlined in the above two links, the PC will give a real time display of many engine parameters such as the engine speed, the TPS (throttle position sensor) signal, the MAP (Manifold Air Pressure), the MAT (manifold air temperature, the fuel injector opening time, the engine temperature, any current or historic error codes and so on. As well as the real time display, the data can be saved in a log file which can be analyzed and graphed using the LOG.EXE program you will find in the downloads from the above software links. Alternatively it can be stored in a buffer and replayed, or stored in a file and replayed.

Here's an example of a log file displayed via LOG.EXE. The top trace is the MAP (Manifold Air Pressure), the center trace shows the pulse width of the signal to the fuel injector (how long the injector is opened for) and the lower trace shows the MAT (Manifold Air Temperature).