A young friend bought a 69 Buick Electra in fabulous condition for cheap because "it would not run". He was a mechanic at a gas station and thought, hell yes, look what I got for cheap! I'll get it running. But he replaced parts upon parts until he had too much $$$ in it. He then came to me and asked, "What else can I do?" I thought a moment, and said "drop the exhaust pipes off the manifolds and start it" Next day...."Hey Mr B" he said, as he ran up the grassy hill to tell me the good news............"sounded like a stock car, wo-maa wo-maa wo-maaa" Guess how I knew what to tell him? My 1967 GS put me through that mess about 1 year after I bought it. I took a hack saw to the pipes and found both sides buckeled inward. Then about one year after that, the ignition resistor wire started putting me on the side of the road....here we go again, but that time most stuff on my car was already new and I had to just think it out this time. I've had a big fat red 12 volt ignition wire under my hood for many years now.
I had a quad that was missing the secondary flap cam. It is a little plastic cam that raises the secondary rods to allow fuel flow. Easy to see if it is there and serviceable. Just push the secondary air flaps open by hand and see if the rods go up.
You haven't ruled out an exhaust issue until you disconnect the pipe/pipes. Then you can move on if need be. Larry
I had low vacuum at cruise speed (70mph) on a 700 mile hwy trip this weekend so I took the car in to to an exhaust shop. They said it is definitely not the exhaust. However, on the way back from the shop the car died and didn't want to restart. The tach was reading erratically and then stabilized at roughly double actual rpms prior to the car stalling. Plenty of fuel. It finally restarted after sitting for 10 minutes. I think I need to dig deeper into the ignition. I've ordered new Delco cap, coil, rotor, points, condenser which should arrive next week.
I can't find anything wrong with ignition or fuel system. Put my crane XRi back in. New coil, new cap, new rotor. All plugs seem to be firing fine. What would happen if my pushrods were too long? This happened after changing the heads. I have no idea how much was milled off the heads before I bought them. My machinist took off .005. I used a cometic .027 steel gasket. It had what I think was a felpro .047 steel gasket before. Could I be floating the valvesor experiencing spring binding with higher RPMS? Gas mileage is down about 20% too.
If the pushrods were too long, and the valves weren't quite sealing, you should be able to see that on a vacuum gauge. If you were into coil bind, you would have damaged the valve train and you would have way more problems than you are having. Get some adjustable push rods and get your pre load right.
Did you ever verify that changes to the air door tension had the predictable effects? Are the secondaries actually opening or is the lockout/choke hanging up? Distributor's mechanical advance working properly? Any of these would fit the description of the problem you are having. All the other suggestions were entirely valid also.
