Cant bleed fuel system

Hello. I have a 1998 jetta tdi and cannot bleed the fuel system. Every time i apply pressure to the return line, fuel comes out, but when the pressure is released, the fuel is sucked back towards the fuel filter, creating air bubbles. Its almost like the fuel line has a vacuum in it, and when i try and suck the fuel out, it just goes right back in.

What exactly are you trying to do?

applying pressure to the return line just puts air into the fuel tank, the fuel tank has a pressure relief of like 3psi . I tried doing what you did a few times and realized that its a waste of time.

Your supposed to fill your filter with fuel and put it back together, then crack open the 3rd "tall" injection line and start cranking.

also get a fuel filter kit if you have not yet done so. this will fix any air bubbles.

Priming the system requires pulling fuel through the IP (via supply line) rather than applying pressure to the return line (downstream from IP). Just park your vacuum pump (or electric fuel pump) on the return line outbound from the IP and go. It doesn't usually take very long for the system to prime if it's sealed properly.

TBH as long as I pre-fill the fuel filter with a decent amount of fuel I've never had a system require a manual prime unless there was something else wrong. With the IP still full the lift pump will typically fill the filter the rest of the way in short order. You might get a few rough spots but it shouldn't stall completely. Also I've actually never cracked a fuel line to do any bleeding, I don't think it's actually necessary.

Steve

I agree. The only time I've had to crack an injector was when I was in the field and needed to do a prime, usually on someone else's car because the fuel filter gelled and starved the IP of fuel.

Some times when i autocross i drive with not enough fuel in the tank and it starves and dies and i just crank it like no tomorrow and pray i dont kill the starter.
always starts

I know that this is going to sound like a dumb question and I'm sure that this is not even the correct thread, but should my vehicle be equipped with an electronic fuel pump? It is a 1997 Volkswagen Passat TDI w/1.9l turbo diesel and a Bosch injection pump. There should be no need for the electronic fuel pump... Right? It is positioned just before the fuel filter and has me wondering what issues occurred before I purchased

Someone added it. VE pumped engines didn't have one.

Maybe he had a leak letting air in when shut down. Who knows?