I wanted to put the "92 problem" into context and explain how it affects the VWRX select monitor software. I may have given people the incorrect impression that this method of extracting data from the ECU doesn't work on 92's at all.
There is a problem on the three 92 cars that have so far been tried, but as Charl rightly pointed out, we don't have a big enough sample group to conclude that all 92's have this problem. Nor are we likely to get one. Ever. Even if the problem does affect all 92's, it is not insurmountable and, depending on your application, you may hardly notice it.
Kevin's VWRX software is the best software currently available and I assume that most people who build one of these interfaces will be running it. (At least until I learn windows programming and produce a better one, specially for the SVX
) This software does not validate the data coming back from the ECU as far as I can tell. It doesn't care if the address bytes in the reply is corrupted and it displays whatever data comes back for the user regardless of whether is it sensible.
The upshot of this is that you can run Kevin's software even if your car has the same problem as mine. If the data from the ECU is getting corrupted then you will see the gauges on the screen fluctuating a lot. It's returning several values a second and unless you are doing some detailed diagnostics, it probably doesn't matter too much to you if some of them are incorrect. You can usually pick out the correct information from the values that are obviously incorrect.
For my application, I
need valid data to examine, to see how the ECU software works and to find the parameter addresses. That is why the corrupt data returned by my 92 ECU has been a problem for me. But now I have what looks like a workable solution.
I hope that sets a few minds at rest.
As I see it, the main stumbling block in this project now is the lack of good data logging software available. I would like to write some, but I don't know how to write windows software and it will take me some time to learn it to a good enough standard.
Phil.