Everything on my good ol' 205 GTi is wonderfully slow. The wipers, heater motor, the dashboard dims when the lights are turned on... Normally anytime I've fixed this on any other machine it's down to something battery related, either the terminals or the battery itself, but, I've had a decent bash here and with a brand new battery fitted, no luck. Even the starter, despite being brand new and freshly cabled, clicks but doesn't turn.
It does fire perfectly if wired directly from the battery.
Curiouser... and curiouser...