Can a bladder infection with no signs of it cause you to pass out?

Yes but mostly not: Urosepsis is a blood infection coming from the bladder that may occur in those not obviously symptomatic. The sepsis lowers blood pressure and can cause people to pass out. It's mostly in the elderly or those with dementia.

Doubtful: First, the question is whether, absent symptoms, you actually have a uti. Even if you have cystitis this is highly unlikely to cause loss of consciousness. See a doctor.