1967 Type 1. No Fuel After Replacing Pump

[AMoger23]

Good morning/afternoon/evening VW enthuthists. My name is Andrew. I own a 1967 VW Beetle that I aqquired about 2-2 1/2 years ago. Ever since I have bought it, it has been having a fueling issue after 10-15 miniutes of driving. I was to beleive it was the fuel pump after some deliberation with myself and a few Type 1 Specicalists. When I replaced the pump,it flet fine. Until the fuel tank drops below 3/4 full; when it gets to that point, it will sputter,surge, and backfire until it comes to a stop, and stalls out.

When you open the rear hatch when it does the ladder, you can see though the filter that there is air bubbles present and is about 1/4-1/2 full of fuel, and not flowing enough fuel to the carb. However, if I let it sit for 10-15 miniutes, the fuel bubbles are no loner present and the filter is full of fuel. And when you turn the key, it starts fine, as if nothing happend.

So, I have come to this forum, asking for help. As I hope someone has had a similar issue as me and has found the resolving fix. I wish to drive longer distacnes than 5-7 miles, wishing to drive an hour or two away for shows and meets.

[Pruneman99]

Does it have the fuel sock in the tank? Is it plugged up with gunk?

[viiking]

^^^Yes.

A restriction on the suction side of pump. Fuel delivery stops but still a partial vacuum on the pump, which slowly sucks fuel through even after pump stops, hence the refilling fuel filter.

1. Fuel sock/blocked outlet on tank
2. Plugged line, bent metal line, squashed line
3. Unvented fuel tank. Run (safely) without gas cap to see if problem goes away

In that order of diminishing likelihood. The other thing to double check is the fuel level correct? That is, is the tank really that full. This is not the cause but an exceptionally low level in the tank will make it harder for the pump to operate. I guess over the years you would have already run with a completely full tank with the same issue.
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1968 1500 RHD Lotus White Beetle since birth. In the hospital for major surgery
1966 Lancia Flavia Pininfarina Coupe - in the waiting room
Discharged: 1983 Vanagon, 1974 1800 Microbus,1968 Low Light,1968 Type 3

[thomas.]

When you changed the fuel pump did you also change the plastic (bakelite) spacer underneath the pump ? Over time if never changed they can swell when hot and restrict the movement of the fuel pump push rod .

[Q-Dog]

I would suspect a poorly vented fuel tank or a gunked up or sticking fuel pump push rod.
_________________
Brian

'69 Dune Buggy
'69 Beetle Convertible
'70 Beetle

[AMoger23]

So viiking, I shall assume it is the fuel sock/outlet. As taking off the fuel cap and or vent seems to help, allowing it to run longer between stallls. But doesn’t resolve the issue. So I thank y’all for the help

[viiking]

So you may have two issues if the removal of the cap improves but does not eliminate the situation.

First you need to look at the gas tank venting, fuel cap wrong(?) any other venting installed?

Secondly you have some sort of restriction from the tank onwards. You’ll have to empty the tank and then check the fuel sock, lines or tank etc.

Have you or any previous owners had a lining put into the tank because sometimes these can delaminate and block the tank or cover the outlet from the tank.
_________________
1968 1500 RHD Lotus White Beetle since birth. In the hospital for major surgery
1966 Lancia Flavia Pininfarina Coupe - in the waiting room
Discharged: 1983 Vanagon, 1974 1800 Microbus,1968 Low Light,1968 Type 3

[viiking]

I guess there is a simple way to prove that you have a fuel delivery problem.

I assume the new pump is functional and the fuel pump pushrod is correct. I assume that the hose connections are correct and not swapped around (suction/discharge). Also the oft-known issue with the bakelite fuel pump pedestal not jamming when heated (as thomas. has mentioned above) has been discounted.

Do this with caution. I'm happy to do this, but you may not be.

1. Park car on a flat surface outside (not in garage).
2. Disconnect battery
3. Have a fire extinguisher or hose handy
4. Maybe a pair of fuel hose pliers
5. Disconnect the suction of the fuel pump, i.e. the hose coming from the fuel tank to the pump . Note fuel will spill. Probably from the pump too. Have some rags handy around the pump to catch the spillage.

There should be a good steady stream of fuel coming out of the hose, i.e. full diameter. If you only get a small trickle, then you have a blockage. You only need the hose off for a second, so spillage will be minimal.

If you are concerned about doing this DON'T. The risk is that you may not get the hose back on and you drain the tank, with the usual consequences. However, the hose is a push on fit, so it should be OK. Hence the possibility of having a fuel hose plier handy.
_________________
1968 1500 RHD Lotus White Beetle since birth. In the hospital for major surgery
1966 Lancia Flavia Pininfarina Coupe - in the waiting room
Discharged: 1983 Vanagon, 1974 1800 Microbus,1968 Low Light,1968 Type 3

[Cusser]

On my own 1970, back in 1984, I developed a fuel tank venting problem.

Of course this was mid-summer, mid-afternoon, on Interstate 10 returning from L.A. to Arizona, and happened between Desert Center and Blythe, so no civilization between those. I stopped on the side of the freeway, did not discover anything wrong, so limped it east along on the shoulder at like 30 mph, and was running low on gas, got it into the station at the Blythe airport west of town. When I opened the gas cap to fill it, a ton of air rushed in, and I realized what had happened.

Anyway, for the next few weeks, I burped the gas cap before each trip. Later I found a metal "tee" connection in the gas tank vent system had gotten clogged with dirt, so was an easy fix once I found that.

So this gas tank venting problem CAN HAPPEN !!!
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1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297