problem with apexi afc

[4g63MMax]

Im having a problem with my 1st gen afc. I have an safc 2 on order but would like to drive my car until it arrives. I just installed 660 cc injectors and installed a used afc. The green wire on the afc is supposed to be rpm input. It is outputting 5 volts and shorting out the tach. Anyone have any ideas??

 

[ftltalon]

are you sure you dont have a bare wire touching something causing the short ?

 

[4g63MMax]

Positive. The green wire from the afc is outputting 4-5 volts when it should be an rpm input. Ive looked all over for info on this afc and ive found very little that is helpful. My first thought was that the dip switches on the rear of the afc were in the wrong position, but I haven't found info on where they should be for a 1g vehicle.