Fuel Pump Pressure & Return 69'

[Phil D.]

A couple of weekends ago, my 69 flooded out and I had it towed home. Investigating, I installed a spare rochester and it also ran with flooding symptoms. I replaced the needle and seat in the original carb, set the float and reinstalled it and it still floods. So I attached a fuel pressure gauge and it read 9psi. Book says 5.5 to 6.5 at idle speed. Before I ordered a replacement fuel pump (I'm pretty sure the one that's on it now is not the original anyway), I thought I'd blow through the return line and make sure it wasn't blocked. There is some back pressure on the return line and I can hear the gas cap vent hissing but I have never done that before on a perfectly operating car, so I don't really have a frame of reference to know how freely that line should flow. I kinda suspect its fine, but not 100% sure. Anything else I can do to confirm thats its a fuel pump problem? I haven't looked at the filter, but logically I can't imagine that to be a the problem. Advice?

[Clem Z.]

Re: Fuel Pump Pressure & Return 69'

A couple of weekends ago, my 69 flooded out and I had it towed home. Investigating, I installed a spare rochester and it also ran with flooding symptoms. I replaced the needle and seat in the original carb, set the float and reinstalled it and it still floods. So I attached a fuel pressure gauge and it read 9psi. Book says 5.5 to 6.5 at idle speed. Before I ordered a replacement fuel pump (I'm pretty sure the one that's on it now is not the original anyway), I thought I'd blow through the return line and make sure it wasn't blocked. There is some back pressure on the return line and I can hear the gas cap vent hissing but I have never done that before on a perfectly operating car, so I don't really have a frame of reference to know how freely that line should flow. I kinda suspect its fine, but not 100% sure. Anything else I can do to confirm thats its a fuel pump problem? I haven't looked at the filter, but logically I can't imagine that to be a the problem. Advice?

take the cap off and blow thru the return line with 5# of pressure,no more as it could blow the lines off of the tank. what you see is what happens when that return line gets plugged. the return line is a "pressure leak" and you will see 9# if the line is plugged. if your fuel pump goes "bad" on the road just clamp off the return hose and you can drive home. been there done that