Replaced fuel pump, still not running…

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Shane65

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Hey FABO, so a few days ago I was gonna take my 318 68 cuda for a spin but it decided it wasn’t gonna start. Tank is about half full… I’ll pour a bit of fuel in the carb, it starts for a second then dies when that fuel burns up. I had a similar problem over a year ago… ended up being fuel pump. So I just replaced the fuel pump, and the fuel filter, still no luck. Also just now replaced the ballast resistor… still nothing. Any guesses? Stumped…
 
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I would check to see if it is getting fuel from the tank to the fuel pump. You may try an electric fuel pump to see if it will suck fuel from the tank. May be a clog in the pick up tube in the tank. Food for thought. Mike.
 
I would check to see if it is getting fuel from the tank to the fuel pump. You may try an electric fuel pump to see if it will suck fuel from the tank. May be a clog in the pick up tube in the tank. Food for thought. Mike.
It’s seems it’s getting fuel… I installed a new clear fuel filter between the fuel pump and the carb and it’s half full of fuel
 
*Rot hole in pick up tube.
*Fuel pump lever not properly under timing chain eccentric.
*got spark?
*carb float(s) stuck closed
I can keep going
Syleng1
 
If it runs when fuel is dumped in the carburetor, then it's certainly not the ballast resistor, is it?
 
Sounds to me like the carb isn't passing fuel.
If you get under the hood and pump the throttle by hand, does the accel pump shoot anything?
 
If it runs when fuel is dumped in the carburetor, then it's certainly not the ballast resistor, is it?
It was dying so fast it was hard to tell if it was dying as soon as I let go of the key, it was a really old ballast resistor and cheap to replace so I went for it, but no luck.
 
Have you checked the accelerator pump as described above?
 
Old standing fuel in the bowl will cause needle to stick. I've had to tap on the front of a 2 brl. with a screwdriver handle every time I attempted to start an old car that sat here for several years, to let it run a while.
 
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Lots of possibilities but we can help you diagnose better.
Ignition:
A. When starting the ballast resistor is bypassed.
B. The original ballast resistor has the correct resistance. Odds are the replacement doesn't. Check with an ohm meter.
C. As pointed it started with fuel so the ignition was not the problem. At least based on what we know from your posts.

Fuel:
A. If the fuel was poured down the throat of the carb, then it wasn't going into the carb bowls. Rather it was going directly to the intake manifold.
B. Fuel pump isn't really needed for the carburetor to supply fuel. All it needs is fuel in the bowl(s). Fuel moves from the bowl to the intake through the low speed circuit(s) by the vacuum created unter the throttle plate(s).
1. Another way fuel moves from the bowl to the intake is the accelerator pump circuit. See post #6 above to test for pump working and fuel in the bowl. If it squirts, the was was fuel and the accelerator pump is working. If it doesn't, then check the bowl.
2. Depending on the carb, its possible to fput a little fuel into the bowl through the bowl vents. Alternatively, one can rig a fuel can and hose to the carb inlet to gravity feed the bowl. Generally its less time consuming to remvoe the carb or remove the top of the carb and see if there is fuel in the bowl.
3. If there is fuel in the bowl, then the low speed circuit is plugged up.

It would not hurt to check the spark plugs to see if there is something obvious they have to show.
 
B. Fuel pump isn't really needed for the carburetor to supply fuel. All it needs is fuel in the bowl(s). Fuel moves from the bowl to the intake through the low speed circuit(s) by the vacuum created unter the throttle plate(s).
1691924874754.png


See MTSC 1966 Carburetor Fundementals for more details about how this works.

available in pdf format at www.mymopar.com
 
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Thanks for everyone’s help… after fuel pump, fuel filter, ballast resistor and lots of carb cleaner, I finally checked the plugs. They were filllllthy black, so I got a new set threw them in, poured a large dose of fuel in the carb and it finally kicked over and kept running. I don’t know if it was just the plugs or a mixture of things but it’s back on the road and running pretty damn good now.
 
Have you checked the accelerator pump as described above?
Good call. If I leave my car sit for a week its a long crank to get the carb primed. Keep on cranking or priming to draw fuel from the lines into the bowl. I get lazy and don't use a prime and Ill crank for ten seconds give the starter a break crank ten seconds more etc. My neighbors think I'm nuts and my car never wants to start but todays gas dries up fast in the bowl.
 
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