Car hisses and backfires

[notcolt]

73 351c. Son ran it out of gas. Next day it would only go 50mph, then once he stopped and came back home, 20 mph. I looked at the fuel filter (I have a clear one on it) and it was filled with rust. So replaced that. Started the car, ran fine until I took it out for a test ride, same issue. Replaced the sender unit (reason he ran out of gas cause the sender unit was bad), replaced the fuel pump, again replaced the filter, plugs and because I had them laying around, the plug wires. Same issue, starts fine, idles, test drive fails again. Took the carb off (Edelbrock 600cfm), cleaned it, installed it, same issues. When the car is at idle, I checked the timing, it has not moved. Not sure what to look for next. Any thoughts? Thanks

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[fakesnakes]

Sounds like rust in the gas tank. You can clean it out and reseal the inside or simply replace the tank.

[Nick.Simonds]

You need to take care of the tank as Fake stated. Also you are more than likey going to have to replace the fuel lines. They are probably filled with rust.

[Oxnard Montalvo]

More information might help.

When you say it idles fine but won't go, if you rev it in park/neutral do the rpms go up smoothly?

When you say it won't go, why? what I mean is does it buck/hesitate/skip or does it run smooth and feel like the emergency brakes on? Is that when it backfires?

As said, are the lines clear?

How did you clean the carburetor?

I'm not busting balls, I think your problem requires a little more detail. It sounds fuel related, but it could be Kid related and running out of gas is secondary.

[cprstreetmachines]

Ask him if it backfired when I died. We get those pretty often. Runs out of gas, goes lean, pops, blows of vac plug and runs like bad after filling tank. Look for any open ports missing plugs.

[notcolt]

Thanks for your input. Tonight I checked the lines (Tank to pump, pump to carb) all clean gas flows fine. Did not drop the tank but will do that.

More info...I can start the car, have it in park and can rev it up and down for a while. Then it starts to wheez/hiss and backfires. I checked all the vac lines for leaks, all fine. Took the carb back off. It is an Edelbrock and it seems to have an issue. Let me state now that this is the first time I have ever had an Edelbrock carb, always have had Holleys. I ran the car until it again was experiencing the issues. Removed the carb and carefully took the airhorn assembly off the body. The first fuel bowl had fuel, the second had very little. So it seems I missed something when I cleaned it. With both floats down, I can blow into the fuel line inlet. When I blow into with the first float up, and the second one down, I cannot. I am assuming that I should be able to. I know Edelbrocks are supposed to be pretty easy to work with, but I find them confusing.

[tx65coupe]

I would just put a new tank in in and replace the fuel line if it is original. You could also blow compressed air through the fuel line. The tanks don't cost much.

I'm not sure about your carb problem you just mentioned, but maybe there is crud in it that is causing the issue.

[RHuckster]

1st off, rust in a carb. is a problem, carb cleaner won't touch it. High pressure air blown through every port might dislodge the rust. If the tank is full of rust the tank needs replacing & the entire fuel system flushed.

Rick

[cprstreetmachines]

Sounds like your crossover tube is blocked. Time for a holley.

[notcolt]

Last night I replaced the fuel line (pump to carb) and carb with a Holley street avenger. The car now runs great. I also dropped the tank and flushed it. It was pretty clean, but have ordered a new tank anyway and will replace that when it gets here. At that time I'll replace the fuel line tank to pump. Thanks for all your help!