I aksed this question in the electronics section and didn't get an answer. If it should be there please move it.

I am trying to get an MSD 6A box to work with an MSD replacement small cap dist. I believe it is number 8366. I am using an 7730 ECM to control everything. I am curious to know if I can use the EST wire from the ECM to the distributor as the timing signal to the MSD box. I am not using a dual connector coil and would like to, if possible, not use the two terminal connector for the distributor. If I have to I will. My problem is I do not know what the distributor module actually does. I could easily grab the C terminal off the module that normally went to the coil negative side and route that striaght to the MSD box. Do I need to though or can I simply tap onto the EST wire and use that for tming signal to the MSD. Thanks

 

You need to use the C- connection from the module. The MSD input puts a 40 ohm (or there abouts) load on the line. Messing with the EST line is asking for problems. Just an FYI, the EST line is also a handshaking line between the module and the ECM. It is also dead during cranking. So even with a amplifier on the line to a CD ignition it can't be used as the engine won't start.

RBob.

 

Thank you. That is the type of info I need and could not figure out from the schematics.