DIS-2 PROBLEMS

[WGTalon]

I am having a real wierd problem that nobody has ever heard of before unless someone reply's different. i just installed a msd dis-2 on my 93 AWD. Did what the directiosn said in troubleshooting etc...msd works as advertised. Although after about 3 minutes of operation the AFC rpm reading will go to ZERO which in returns eliminates all your fuel trims and that adjustable curve that the afc allows you to use.....here is the thing though. The tach on the dash still works and both the afc rpm wire and tach wire use the white wire that the tach output is running to.
I havent really solved this problem just elimnated every possible wiring and component in the system and narrow its down to a voltage issue. So installed a 3.5k resistor on the green wire of the afc thinking the afc had been getting too much voltage and bammmmm it worked...but only for 10 minutes...so i stepped the resistor size up. 10k did the same thing. I am now on a 22k resistor that has yet to fail me but it takes a little while for it too warm up and get an rpm signal to the afc, but after that smooth sailing.
I was just wondering if anyone has had similar problems w/afc and dis-2? Thanks for your time.

[Moto'freak]

That happened to me a while back and I just installed the tach adapter from MSD and everything works just fine

[WGTalon]

I have read on some posts that you didnt need the tach adapter. But i guess you do unless i found a way to cheat the system. How much did the adapter run you? Thanks

[destrux]

I know this is kind of old but I wanted to add something anyway..


The extra load the AFC signal wire puts on the tach signal line probably was responsible for the problem. It seems like the DIS-2 is right on the edge of needing the "tach adapter" (which in reality is a tach signal amplifier, not an adapter) when it's intalled by itself. Maybe try soldering the connections to increase the amount of voltage making it through where the butt connectors are that MSD supplied, that might be just enough to prevent needing the "tach adapter".

[Blackboost]

Moved to Electronics Tech...