I have a shitty hydraulic tensioner on my mechman 320. it slipped when I started the car, but now it's good. Only time it slips is when my AC is on blast at idle and music turned up then I accelerate. The main thing if its a hydraulic tensioner is to make sure it's new/good condition and let it tighten by itself. It took a few days for me. Second if it doesnt work replace with a bigger idle pulley, shorter belt, or new tensioner. Getting import cars to work on after market alts is a bitch and there is no way around it. I absolutely hated the process but I can't complain that with my saz3500 volts stay at 13.6