swap problems
 

swapped in a new d into my 00 si.....motor runs fine, idles a bit high but runs good, problem is the tach and speedo jump all over the place, the lights flicker on and off on there own as well....like they will dim then get brighter, then dim then get brighter....the car runs normal when started until i rev it then the problems with the lights dimming etc starts. took the car around the block today and noticed my stereo shut off and would come on then shut off again, the lights would stop dimming for a bit then dim again and the tach would start going crazy.......brought the car home and it wouldnt start.........no battery light came on or anything.....any ideas? btw i checked all grounds and my batt terminals

it def sounds like a ground fault. I know you said you already checked, but really there are like scores of ground points at all parts of the car... time to check them all.

def sounds like a ground problem..
that or the alt. has gone for a shyt

howd you check the grounds?

figured it out, was the sp alternator or w/e fuse