at the end of the day if it's cold enough or the rodent is hungry enough nothing will stop it. a warm engine bay is very welcoming and it comes with tastey soy wiring as a snack. I live hear a forest, all sorts of critters nearby. during winter I find footprints in the snow from who knows what. but never any rodents in my engine bay at my house and I don't use any deterrents
the only time I had a rodent chew my injector wires was when I parked at a train station for a day interestingly enough. it was an extremely cold day and the rodent was probably in the right place at the right time. my 4runner still made it home with 2 cylinders misfiring but it was a struggle. I had to put it in P at stoplights or it would want to stall. these things are definitely over built and under stressed for most of their lives which is why they last so long