I had desired it with an ardour that far exceeded moderation mean?

"Desired" means "wanted". "Ardour" means "passion". "Moderate" means "not excessive", so "moderation" means "without excess". To "exceed" means to be more than.

So, "I had wanted it with a passion that was more than an amount that was much more than it would be without excess." OK, so maybe that double negative is not what we want not to avoid. Let's say "I had wanted it with a passion which was very excessive."

But the original sounds cooler.