[Diy_efi] missing 'PCM SYNC' using DataMaster

[Rich Rubel]

I have been going nuts trying to get my '86 Corvette working with the  
DataMaster software so I can get someone to adjust a custom chip for  
me.  I have a very simple ALDL interface cable that consists of three  
wires (pins A, E, and M) soldered to the BACK of the ALDL port, which  
run through the ALDL adapter circuit, to a serial cable to my PC.   
This setup worked fine with WinALDL, as far as I could tell - I was  
getting reasonable data when logging.

I also have a Prominator with a copy of the stock PROM installed.

First thing with the DataMaster package is that 85/86 Vettes require  
a "10k resistor modification" which I found the circuit for on the  
'net.  I added the resistor inline going from pin B to the wire  
coming from pin A.  Once I did this, DataMaster was able to test and  
identify the PCM.

However... every time I try to read data from it, I get a "No PCM  
Sync" message and a counting timer.  No data.

Any thoughts?  The people at DataMaster have been less than helpful;  
I seem to get secretaries rather than support staff.

Thanks.
- Rich Rubel