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66nova guy 12-20-2003 12:23 PM

gas runs back to gas tank...

If my -66 Nova Wagon has been parked for two days or more the gas seems to run back into the tank. The clear fuel filter before the carb is empty and I have to make several attempts to start it before the fuel gets pumped up to the carb again.

So, is there some kind of valve in the fuel pump that has stopped functioning?

Pony 12-20-2003 12:45 PM

Next time you park it leave the gas cap loose. If the vent is plugged or it's not a vented cap you could be creating a vacuum in the tank (pumping the fuel out with no way for outside air to enter and equalize the tank pressure) and when you shut it off it's sucking the line/pump/carb empty trying to equalize it's pressure with the outside world.

western star 12-20-2003 12:48 PM

I had that same problem and it turned out I had a pin hole in the diaphram in the mechanical fuel pump. Replaced pump and ta duh....fixed. Worth a look.

Kevin45 12-20-2003 01:17 PM

My vote is for a bad fuel pump also. Just like holding your finger over a straw. As long as there is not a pinhole the fuel will stay in the line. Small pinhole and it will run back.


camaroman7d 12-20-2003 01:40 PM

I would agree it's the pump, this is a typical symptom. The pump should prevent the fuel from bleeding back.

A vent problem would typically show up while driving, by starving for fuel or stalling. Sometimes it will cause hard starting (hot) as well.

Dubz 12-20-2003 04:13 PM

you could always put in a one way check valve in the fuel line, but as mentioned the pump may have a problem

4 Jaw Chuck 12-20-2003 04:21 PM

Replace the pump, check valve is leaking.

66nova guy 12-28-2003 04:35 AM

Thanks guys! I have a pump with 3 fuel lines from a 79 van. Can it be made to fit my 60s 327 by plugging one of the lines?

(I have the same problem even if I remove the gas cap when parking.)

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