Car will not start help please?

I own a 1995 mitsubishi Galant, Auto, fuel injected. and recently i added a turbo. this happening i had the ex-oust down pipe run kinda by the alternator but seemed to have no problem.and when ever i try to start the car i hear a click sound which is my starter trying to engage, i checked my starter and solenoid. they work fine, i checked the battery its good, and the connections seem fine and i ran out of things to check can you guys help thanks. oh and does the connections to the alternator effect the starting?