[66sprint6]

I took the LeMans out on the weekend. We've never had a problem with it until now. I came to a straight, open stretch of road and floored it. There was no problem with the acceleration. The car responded well, but after about 1/2 a mile, it started bucking. Eventually it died, like it ran out of fuel. It wouldn't start on it's own after that. I had a small gas can in the trunk, so I poured a little bit down the carb, which got it going again.
I went home and told my son what had happened. So we took two vehicles down to the same open stretch of road and I tried it again. Same thing, accelerated very well, then died a little down the road.
I thought that it might be the fuel pump, so we replaced it with another one that I had, and know that it works. Same result. When I replaced the pump, I had my son crank the engine with the fuel hose going into a container instead of the carb. Nothing came out while it was cranking. I had him start the car and fuel did eventually start coming out of the open end into the container.
Is fuel supposed to come out of the line when just cranking the motor? Could there be a problem with something in the line or the tank?

[Scott65]

Yes, fuel should come out when cranking. Have you ever replaced, or removed the sock on the pick up in the tank? Any old rubber hose? Checked for bends or kinks in the hard line?
ETA: check for loose hose clamps anywhere. Air leaks will cause no fuel while cranking too.

[steve25]

Sounds like a classic case of as posted above a restricted fuel sock or cracks in the rubber fuel line at the two points where it’s used on the car, or both conditions may be happening with the car.
Dry rotted old rubber fuel line on the suction side of the pump many times can crack, yet not leak fuel
So the pump finds it much easier to suck air thru Those cracks when it’s being called upon to deliver large volumes of fuel.

The out come is what you have experienced with a dry fuel bowl(s) in the Carb .

You need to replace all the rubber line used on the car and since there’s some used above the tank , the tank must be dropped to get to it, so then is the perfect time to replace the Sock on the end of the sender/ pick up also.
Be sure to get a new seal for the tank sender also when you order up the Sock.

I would also check closely for pinches in the run of steel line from the tank to the fuel pump.

Sometimes you have jacked up the car and don’t realize you have pinched the line , or a rocks can also get kicked up and pinch a line in certain areas.

[Kenth]

Clogged tank ventilation?

[KEN CROCIE]

I found significant rust buildup inside of the steel fuel line on a T/A I was working on a few years back.

[gto19]

Where would one buy a replacement sock for a original fuel sender ?

[66sprint6]

Thanks for the replies. If it's a problem with the fuel tank, sending unit or line, then I'll probably just go ahead and replace it all. Dang. I was not looking for another job to do on this car. I guess the silver lining is that I have most of the parts in stock. Is the reproduction sending unit any good, or should I try to service the original one with a new sock, etc.?

[steve25]

The sponcer’s of this site carry both size replacement Socks, 5/16” and 3/8”.

The 65s only had 5/16” lines and since your added hp now would be a good time to go up to 3/8” starting with the sender all the way forwards to the pump.

[66sprint6]

Looks like I'll have to order a different sending unit. There's only one listed for our car, which has A/C. It has a 3/8" supply and 1/4" return line. The one that I bought for the Tempest has a single 5/16" line.

[b-man]

The 5/16” fuel line was used up through the 1967 cars which included ones equipped with Ram Air and HO engines. It wasn’t until 1968 that they started using the 3/8” line on the Pontiac A-body cars so check your fuel line size.

You can order the line you need in 3/8”, that’s what I did when I replaced the original 5/16” line on my Tempest.

[66sprint6]

After a lenghty search,I found that the only replacement sending unit available is definitely one with a 3/8" supply and 1/4" return. Our host carries it. So I'm thinking that I may service the exisiting sending unit (sock, etc.), blow out the exisiting steel lines, replace the rubber bits on each end, and get the return line hooked back up. The current set up as we got it is a single supply line and the return is blocked off with a small bolt at the fuel pump end.

Wth the return line, I've seen two different conditions. One where the fuel pump has the return line built in, and one where the lines go to a filter, which has the return built in as well. Which one is correct for my '67? Or are both correct? Again, mine is an A/C car.