Fuel pump failure?

[Snoopy1971]

OK, new problem … Backstory, I dropped the engine to chase an oil leak, so replaced the oil cooler and seals, reassembled, ran it remotely … No oil leak!!! … Then did a compression test, had zero in #3, disassembled again and discovered a nice chunk missing from the piston. So I just also did a top end rebuild. New pistons, cylinders, and heads. I replaced my fuel filter because there was a hunk of crap in it (which I had replaced 13 months ago), and the all the hard and soft fuel lines were also replaced 13 months ago (including the hard line through the tunnel, ran a new line through the drivers side when I accidentally hit the line coming out the chassis when I was changing the clutch cable ).

So after the top end rebuild, I ran the engine remotely outside of the car no problem 2 weeks ago. I put the engine back in the car, and after fighting with a Chinesium starter bolt, I got everything squared away. Everything connected, etc. Go to start it, and it wouldn’t start. Or I should say, it starts, but wont stay running longer than like 2 or 3 seconds. I squirt some gas in the carb to help it along, and still same result.

I look down the carb while I’m pumping the throttle arm on the carb, and at first, I see some gas come out, but then after that, it either spits some gas out (not constant flow) or no gas at all.

So sensing a fuel delivery issue, I started troubleshooting. I removed my fuel filter I had just installed (I could blow through it just fine … mmmm gas tastes good!!!), and temporarily replaced it with a piece of tubing (same I used for the new fuel line last year). Tried to start it … same result.

Then I eliminated the gas tank, fuel line, fuel filter entirely and removed the suction line of the fuel pump and put a line from it into a gas can (just like when I ran it remotely) … same result.

Then I put it all that back the way it was and removed the fuel line at the carb and stuck that in a jar, removed the wire to the coil, and turned the key to see if any gas would come out at a consistent flow … it didn’t. Came out at first, then didn’t, as seen in this vid:

https://youtube.com/shorts/7Z9k-q0j5rI?si=sEWjoWnOv1Nt7yxb


So what is everyone’s thought on this? Fuel pump crapped out right? Maybe the diaphragm is ripped inside? Only other thing I can think of is something blocking that short run of fuel line from the pump to the carb. I haven’t actually taken that off yet to verify that it’s unblocked. I believe my fuel pump is aftermarket, but in the style of the oem Pierburg ones that were for ’62-65 (I have a ’6, that has the dome top on it. … I mean what are the odds that the fuel pump craps out when I get it back in the car, when it just ran fine 2 weeks prior.

I haven’t taken the fuel pump off yet or taken the top off it off yet to see if the diaphram is ripped. Thinking of one of the rebuilt squaretop Pierburg ones from the Sparxwerks guy.
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1968 Bug

[my3bugs]

you sure you have gas in the tank ? i recently got a square top pump for my bug to replace the disposable one it had . but i kept is as a back up cuz it still worked . some of these pumps have like a check valve inside so fuel doesnt flow when its not running ........

so try taking the fuel line off before the pump and confirm you have gravity fuel flow to there ??? just making sure you have gas getting to the pump ???

[Cusser]

[67rustavenger]

I've had a fuel pump loose prime in the past.
I used a small squeeze bottle to fill the fuel line between the carb and pump. Placed the pump inlet line in a gas can and cranked the engine, condenser wire disconnected and observed fuel flowing into a catch bottle.
Reinstalled the pump inlet and outlet lines and the carb line.
Fired right up.
Maybe you can try this to see if your pump lost prime.
_________________
I have learned over the years.
Cheap parts are gonna disappoint you.
Buy Once, Cry Once!

There's never enough time to do it right the first time. But there's always enough time to do it thrice.
GFY's Xevin and VW_Jimbo!
2003 Astrovan? GFYS again, Xevin!

[Snoopy1971]

[Snoopy1971]

[my3bugs]

i would NOT be clamping down vice grips on a fuel line i want to use ( i wonder if something happened there ?

i have colorful wooden golf T's in all my tool boxes , quick n easy to use . perfect for most VW size fuel lines .

[Snoopy1971]

[lboos]

Snoopy,
If you disconnect the inlet fuel line going into the fuel pump, fuel from the tank should flow at a small stream, if it does, you got a fuel pump prob.

I also have a 1971 S/B, my prob. was when I replaced the tank the fuel line from the tank got kinked and blocked the fuel from the tank.

[Cusser]

[halfassleatherworks]

did you by chance mix up the inlet and outlet?

[lboos]

Cusser,
When you replaced your tank, how much slack did you leave in the fuel hose to make a loop ?

[Snoopy1971]

[Cusser]

[lboos]

Cusser,
Thanks.