I have a 1979 Coupe DeVille witha 7.0L V8 and a stock Rochester Quadrajet 4B Carb. I recently removed the entire distributor assembly. I reinstalled it the same way I had taken it out. All the spark plug wires where put in according to an aftermarket manual. When I tried to start it up, it turned over once, then detonated in the intake manifold,(I think that because lots of smoke starts coming out of the carb). It will on occasion start, however. When it does, it idles high like usual, but when it backs down, the motor starts jumping around under the hood. One aspect of its behavior that makes me think that it isnt the timing is the fact that it will never start with the air cleaner on. On occasion it will run, but the throttle bounces so bad that it eventually stalls. I have only two hypothesis:
1. There it something wrong with the distributor
2.The carb is calibrated wrong(wouldn't know why)
Thats all the information can give and i hope someone knows whats wrong.
:banghead:

It sounds like it is too lean, given that it won't start with the aircleaner off. The jumpy idle and such leads me to believe vacuum leak somewhere, which would lean it out.

You didn't say what prompted you to pull the distributor to begin with, but it also sounds like it could have jumped time.Was it running like that prior to the distributor removal?

The car had sat for about 8 years so i've been cleaning off carbon buildup wherever I can. Thats why I took it out. (Boy was it caked with that crap) AS for your second question, no, not really. There was occasions when the engine would be a little overly jumpy, or times when it would Idle really high, but not consistently. Usually it runs really well.

i think you might of mixed up a wire. The firing order is stamped right on the manifold. On that motor cylinderone is the right front not the left front. The right side has 1,3,5,7 the left is 2,4,6,8...

There's a vacuum advance feature of the distributor, maybe you disturbed something related to that.

I made sure that the firing order was correct, twice, reseated the dustributor, checked it out on the inside, and made sure the vacuum hose routing was all correct and all connected right. Everything was fine so far as I couls see. I'm going to buy a cap and rotor kit, new wires, and see what that does(spark plugs are brand new bosch platinums). I'll see what that does.

Have you changed the gas filter?
Also
Spray some carb cleaner down it and let it soak
Also put some through the carburater with it running (Spray the cleaner into the cap or a cup and slowly pour it in,, because if you just spray it in there while it's running I've heard that the can could explode and take off your hand)

If you've confirmed all the basics are in order, rotate the crankshaft in either direction and see if there's much slop in the timing chain before the rotor turns. Ideally, the rotor should turn within just a few degrees of crankshaft rotation. It might have jumped a tooth or two previously, but still ran and now it's jumped for real. Don't be surprised.

I got all that taken care of. It was timing. The dist. wouldnt rotate far enough to be at the right timing mark, so I ended up having to rotate the spark plug wires one whole place. Its only 1 degree off, but it runs fine. Actually now the car is messed up. It will stall if too much gas is applied. And by too much I mean normal pressure on the pedal. I talked to a mechanic and he said it was maybe the accelerator pump. That sound right?