[Texastang]

I have a '70 Mach 1 w/a 351C 2 bl autolite 2100. The car will not idle when it gets to operating temperature. The car will run fine once you get to freeway speeds, but it will not idle or allow you to apply the brake and come to a stop without dying. I have put on a rebuilt 2100 and the same problem exists exactly with that carb. The car will even die as soon as it gets to normal operating temperature if you start it up and let it idle for a few minutes. It does idle when the idle is working with the choke on and the engine at a cool start up temperature. I have plugged all vacuum lines except the transmission(FMX) and the power brake line so I don't think it is a vacuum problem.

Help, where else do I check.

 

[sidewinder]

Have you tried adjusting the idle mixture screws? It sounds to me like you need a richer mixture at idle.

 

[KEVIN69MACH1]

You might check the brake booster for vaccum leaks.
I had a similar problem with my Jeep CJ and the power brake booster was leaking vaccum.

 

[Texastang]

I have not checked the brake booster for vacuum leaks. I guess I should block off the brake booster and just let it idle and see if it dies. I was also wondering if maybe the fuel pump has problems getting enough fuel at idle. Any chance the fuel pump may be the problem?

 

[Texastang]

I did not adjust the idle mixture screws in my original carb and the new carb said it did not need idle screw adjusting. I assumed that since the same problem was present with 2 different carbs that it was probably not a carb isuue. Anyone else agree or disagree?

 

[Texastang]

I blocked off my vacuum port at the intake and now it will idle without dying after it gets warm. I then tried to put it in gear and it still dies. I took the fitting out of the booster and it still had such a tight seal that the booster was still holding vacuum. I am worried that the intake is leaking, although the car is sucking excellent vacuum, so much so that I cannot pulll off the plugs to the vacuuum port while it is running. Two different carbs and the same prob, man I need help.

Anyone else have ideas?

 

[Texastang]

I replaced the fuel pump and found out that 3 of my 8 contact posts under my distributor cap were dirty. They had a ceramic-like carbon deposit that would not come off with a light scuffing of sandpaper. I had to scrape it off with a small screwdriver. The car did not die for a long test drive after that. It did start dying again after I got home and tried to back into the garage. I am going to replace the rotor and dist cap. I do have the pertronix ignition under the cap.

Anyone have more suggestions if the new cap and rotor don't completely solve the problem?