I bought an '83 320 that had set up for several years and now seems to be plagued with multiple problems. The one I'm working on now is the poor idle and generally rough running engine. It seems to be flooding. There is a molded hose about 5/8" i.d. which is in the shape of a modified "U" in the vicinity of the intake manifold on the top of the engine. While the car was idling, I disconnected this line and there was a huge sucking sound and the engine started racing with high RPM's. (Previously I had set the idle up just to improve the idle.) It seemed that the air/fuel mixture had finally equalized though. The thought that came to mind was that maybe a big mud dobber's nest was clogging up the air intake, as it seemed starved for air. Any idea as to a solution? (I had, a while back, tampered with the fuel pump relay and was thinking that possibly it was running constantly now, causing excess fuel to enter the cylinders.) The air cleaner is removed so it is not a dirty filter. Any way to get more air flow? Thanks.

Well, bringing your ride back from slumber is a process that includes cleaning up the fuel system, taking off the intake to clean out any mouse nests that may have appeared, etc. Aside from that, you have an air leak somewhere. The engine should die if:
You pull the dipstick out
You take off the oil filler cap
You take off a hose like you did

She operates on a vacuum...if you have a vacuum leak somewhere like a cracked, hardened hose, someone could have messed with the mixture to compensate. You know this has happened when you pull the dipstick (or hose, whatever) and the engine revs instead of dies. You have a vac. leak somewhere, and you should replace all the hoses to hunt it down. The rubber intake boot that connects the AFM to the bottom of the intake is a bitch to take off, but you probably should in order to check it for cracks and to spray carb cleaner in the throttle body. Wouldn't hurt to remove the AFM itself and clean it out, but that's up to you and your comfortlevel with this sort of thing. Regardless, you should check the hoses that connect to the intake boot for cracks also, especially where they connect to the boot on the hard plastic piece that protrudes. You can buy a kit for these from http://www.bmpdesign.com/ that has all of the hoses and intake boot.

After you get that sorted out, you can then tune the car's Air/Fuel ratio and idle speed. Use the search function and look for: Vacuum Leak, intake boot, mixture, etc for more info.

BTW, if your Warm UP Regulator is gummed up, it can flood the engine and cause all kinds of headaches trying to tune.
Cheers,
John

Pulling off a small line is not likely to stall the engine. It does increase the idle alot though and of course a very high idle is going to be smoother. You haven't described anything yet that is a problem.

The fuel pump relay DOES run constanty. Someone needs a Hayne's manual.

It's a problem when the engine races to @ 6000 RPM when a hose is removed and barely chuggs along otherwise. Too much fuel and not enough air. (Sorry for the confusion; the hose is @ 5/8" id instead of 5/16".) The warm up regulator sounds like a good place to start. I have a parts car so I will replace it. My Chilton's manual does not seem to cover this issue. I appreciate the info. Waferman and Layne.