Keep in mind that because of the Jeep's aerodynamics, when running at anything over 35mph, the air is actually coming in from BEHIND the Jeep (as in where the fuel tank is). I have had my fuel tank hoses leak, but they were not leaking enough for the gas to fall to the ground, and that was where the smell was coming from.
What you can do is try to sniff out a general location; if it's coming from around the tank, it's probably one of the hoses that cracked, and you need to drop the tank; it's not all that complicated, but it's a bit of a pain to get it to come loose because the fit is tight and the filler hose plugs get in the way for the tank to clear the leaf spring (assuming that the 89 has the same tank as the 94; not sure it does).
If the smell is coming from near the driver's side rear wheel well, then it could be iether the fuel filter or the hoses that connect to it. The one right behind the filter (the one with the 90* bend) tends to crack and leak, so it could also be coming from here...
Hope this helps!
Felipe