aljohnsonii

I have a 1989 Camaro and I put a 1991 tpi harness in the car my my major problem right now is that I can't check my check engine light I wAs able to check it about a week ago I have switched the computers and still not letting me check it I checked all the fuses when I jump the check engine light my shift light flashes then the check engine light stays on all the time no matter what I really need help so I can find out why my car is not running so I can drive it also does anyone know how to fix the factory tach on a 89 tpi going down the road its at 7000 rpm and I know that is not right and at idle it is ad 5000 please some one heLp with the check engine light I could care less about the tach if I cant drive my car but if you know a easy fix that would be a start thanks