440 starts, but doesn't stay running

[68Dodge]

Hello,
I have a 68 coronet with a 440. Project car and finished putting the engine and everything back together. Now it starts, but doesn't stay running. Fires up when you put gas down the carb and after that burns off it shuts down. It has good spark (dual point distributor, new points, cap, rotor, and condenser), new MSD coil/ballast resister, new plug wires, and plugs. New edelbrock thunder 650 cfm. All new intake gaskets/valley pan. No sign of vacuum leaks. When I crank it over, shows light on timing light. I haven't put all the interior/interior electrical system back in...so the key ignition switch is not grounded. I have hooked up the dash assembly and key ignition switch so i can crank the motor. It starts fine, but as soon as it's done burning the gas I poured down the carb, it dies.

Does this sound like a bad Carburetor? Ballast resister? Vacuum leadk? Or Ignition switch ground?

I've also took the Carb apart to see if the floats were stuck...they weren't. The car acts like it's not drawing the fuel from the carb...but need help identifying this issue. Thanks for any help.

 

[bigmanjbmopar]

We just saw this from another member, bad ballast I think. Have you changed it yet? I think someone said that was a classic ballast fail symptom

 

[1badstroker]

A bad ballast resister most time is when you go to start the car with the key, You turn the key to start and as soon as you release the key to go in the run position the engine will quit. I still carry a spare with me every where I go with the car along with several other easy parts. Good luck and hope this helps.

 

[Hemi Rebel]

Well, you said it runs if you pour gas in the carb and shuts off when the gas runs out. Disconnectthe fuel line at thw carb and put a rubber hose on the line and run it into a container then crank the engine and see how much gas you get out of it. Sounds like either no gas in tank. Bad pump. No pump pushrod or restrictions in the line

 

[monaco66coupe]

I'm wondering, do you have fuel pressure? unhook the line to the carb, and crank the engine while holding a cup to catch fuel. If you don't get any, then that is possibly why it dies after the fuel burns off. If you have fuel, look down the carb and pump the throttle, see If anything Is coming out of the venturi. If you have all this, then an
electrical problem as mentioned earlier could be the next thing to look at. Hope that helps,,,,,

 

[bigmanjbmopar]

Yep that was it, I haven't had a ballast in soo long now forgot how they react

A bad ballast resister most time is when you go to start the car with the key, You turn the key to start and as soon as you release the key to go in the run position the engine will quit. I still carry a spare with me every where I go with the car along with several other easy parts. Good luck and hope this helps.

 

[68Dodge]

Put a new ballast and still the same. I have a glass fuel filter and shows good flow of fuel. Is it too much fuel psi? Possible bad carb?

Thanks for all the replies.

 

[cwhubb]

I had the exact same problem, it turned out to be a problem with a phenolic spacer, it had a small chip in it and it was sucking air, I got rid of it and problem solved

 

[Cornpatch MO]

Hello,
I have a 68 coronet with a 440. Project car and finished putting the engine and everything back together. Now it starts, but doesn't stay running. Fires up when you put gas down the carb and after that burns off it shuts down. It has good spark (dual point distributor, new points, cap, rotor, and condenser), new MSD coil/ballast resister, new plug wires, and plugs. New edelbrock thunder 650 cfm. All new intake gaskets/valley pan. No sign of vacuum leaks. When I crank it over, shows light on timing light. I haven't put all the interior/interior electrical system back in...so the key ignition switch is not grounded. I have hooked up the dash assembly and key ignition switch so i can crank the motor. It starts fine, but as soon as it's done burning the gas I poured down the carb, it dies.

Does this sound like a bad Carburetor? Ballast resister? Vacuum leadk? Or Ignition switch ground?

I've also took the Carb apart to see if the floats were stuck...they weren't. The car acts like it's not drawing the fuel from the carb...but need help identifying this issue. Thanks for any help.

Not mentioned, but gas to the carb and to the fuel pump from the tank would be the first thing I would check.......................MO

 

[monaco66coupe]

Is it coming out of the venturis? If it is cold out, the carb may simply want the air horn closed. a lean carb can do
that, timing too advanced can, a plugged Idle circuit. I keep going back to fuel, because dumping raw gas down a carb does one thing, it creates an extremely rich condition for a short period of time. Maybe unplug the vacuum
advance, to eliminate the possibility of the rapid increase in RPM advances the timing too far, too quickly.
It would be lot easier if we all were standing right there!LoL

 

[snakeoil24]

GAs, air and electric! Check condensor if you have points!

 

[Hemi Rebel]

I would take the line off at the carb and make sure the gas is getting there. Just cause you see gas in the filter doesnt mean its coming out. If you are getting gas to the carb, then I would pull the top of the carb off and see what is going on. Needle and seat stuck closed or float jammed up or something.

 

[Dennis H]

I had the exact same problem, it turned out to be a problem with a phenolic spacer, it had a small chip in it and it was sucking air, I got rid of it and problem solved

Hope you replaced it?

 

[cwhubb]

@ dennis, I went with an aluminum spacer had no problems since

 

[Photon440]

Do you actually get a good squirt of gas from the accelerator pump when you work the throttle? If so, you shouldn't have to be pouring extra gas down the carb. If not, find out if there's no gas in the float bowl. Maybe the needle is stuck shut.

 

[68Dodge]

Thanks for everyone's reply! I finally found the problem...broken wire from the ignition switch to the firewall. Car would fire up when cranked over, but died as soon as I stopped (but not in the shut off position). Tried everything, then started from the inside the car and realized there's a broken wire. Again, thanks all for the replies, it was helpful.

 

[cwhubb]

another one for the rolodex Glad you found the problem, good luck with the project