what is that hose??

[xj2fsj]

I did the distributer upgrade today, cap, rotor, adapter, and wires. It has a much smoother idle and maybe a little more off the line(?) but any way, here is the question.
I was having problems with backfiring, it was doing it under two circumstances. First, in park or neutral, if I revved the engine it would backfire after I let off the throttle, more or less depending on how much/long I held it open. Second, on the highway, after i had pushed to reach speed and let off the throttle to cruise, it sounded just like a jiffy pop under the hood for ten or fifteen seconds.
here's the weird part, I pulled a med. diameter hose off the engine, it was blowing warm air (exaust?) from one manifold to the other. It passed between the distributer and the carb. across the throttle body. what is this and why did it stop the backfiring?
'82 wag 360 2brrl\727\np208\44-20

[arter]

Sounds like part of your emissions system, one hose coming from the air pump (under the power steering pump) to diverter, and two going to check valves and tubing attached to each exhaust manifold. Checking my trusty Chilton's, it says that exhaust backfires can be caused by air leaking into manifold vacuum (spray carb cleaner around intake man and carb base and listen for idle to smooth out), exhaust leaks (visual inspect), or what may be most interesting for you, faulty air injection diverter valve, that tomato paste can sized thing with holes in the end the hoses come out of. Could try swapping it out and see if that takes care of the prob. Guys on the board may have more for ya.

[xj2fsj]

if I leave it disconnected...?

[ibnfe]

I took all that mess off of my '85. Biggest thing is to make sure you don't have any vac leaks or openings. Be sure to plug all the holes you open, otherwise you may be creating a bigger problem. I'm not sure what line it is that you pulled or even if it's needed or not. Look HERE (http://www.ifsja.org/tech/fuel/pictures/8cylvac.gif) and see if you can tell us which line it is.

[Ralph]

If you leave that hose disconnected, you will have exhaust leaking directly into your engine compartment rather than out through the exhaust pipes. The check valves mounted to the AIR tubes on either manifold are notorious for burning out.

I would offer that the cause of your backfiring is in fact a manifold/vacuum leak. Your smog system diveter valve, for example, has a small vacuum line attached to it. Check all of these out and see if you didn't forget to attach a hose somewhere.