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Fuel pump problem.


Guest Jet

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my '67 Wildcat won't start and I've traced the problem to the fuel pump by using starter fluid. I'm now trying to figure out whether I have a clogged line leading to the pump or a malfunctioning pump. The pump has two lines leading to it, one is larger than the other - I'm not sure, but would the larger one be the return line? I removed the smaller tube from the pump and placed my finger over the tube on the pump, then had someone crank the ignition to test for pressure and I didn't feel any (though I'm not positive if I could with a mechanical fuel pump.) I'm a bit lost, where should I go from here?

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67 Wildcat doesn't have a return line. You should have a line coming up the frame from the tank and another to the carburetor.

Try replacing the fuel filter if it hasn't been replaced in living memory. This is the cheapest part to buy and easiest to replace. You can disconnect the fuel line at the carb, stick it in a 2 liter pop bottle and turn the key. There should be healthy squirts of fuel, say about a half cup of fuel in 3 or 4 squirts. Disconnect the coil so the engine can't fire up.

Was the car running up until today or has it been off the road for a while? It can make a difference where to look.

If you suspect a clogged fuel line you can disconnect it at the pump and blow through with compressed air.

With the fuel lines disconnected you should be able to feel suction on the intake and pressure on the outlet if you turn the engine over. 2 to 5 pounds of pressure, not a lot but you should feel it if you cover it with your finger.

If you have a vacuum/pressure gauge you can tell exactly how much pressure you have but not many people have them anymore.

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Bet a dollar to a doughnut that your pump is original or an old rebuild, and the ethanol in our new gas has attacked the diaphragm....and now it won't pump...

If so the pump will need to be rebuilt with a newer diaphragm or replaced with a newer unit, either resistant to the 10% stuff...

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Thanks for the help, I'll try out your suggestions. Yeah, it must be the pump because I think I would have felt at least some pressure from the intake valve.

I honestly have two lines going from my tank to the pump. Here they are connecting to the tankpost-97844-143142294981_thumb.jpeg

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Thanks for the help, I'll try out your suggestions. Yeah, it must be the pump because I think I would have felt at least some pressure from the intake valve.

I honestly have two lines going from my tank to the pump. Here they are connecting to the tank[ATTACH=CONFIG]224958[/ATTACH]

While I'm not a Buick expert, the same-year Oldsmobiles did use a return line on some applications. The return line is the smaller of the two (usually 1/4").

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I'll add that while the fuel pump may very well be the problem, check the rubber lines on the suction side for cracks. Since this is the suction side, any cracks will let the pump suck air, which will cause the same problems you've described. The hose from the tank sender to the hard line on the frame is the most likely candidate.

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Bet a dollar to a doughnut that your pump is original or an old rebuild, and the ethanol in our new gas has attacked the diaphragm....and now it won't pump...

If so the pump will need to be rebuilt with a newer diaphragm or replaced with a newer unit, either resistant to the 10% stuff...

We really do need the "like" button working.

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