03 ALH Jetta with no fuel in clear line from filter to IP

What can I check? There's no fuel in the clear line running from the filter to the IP. Any help is appreciated!

EDIT: I can not pull a vacuum from the fuel return port (with my thumb on the fuel return line to cap it off). I can blow into the fuel supply port and hear it coming out near the area with the 4 fuel delivery valves.

Does this mean I need a reseal?

EDIT: The initial 'listening' guess at air coming out at the fuel head was truly air coming out at that location. I poured soapy water over the IP, plugged the return line with my thumb and had a helper (my son) put 5psi of air into the fuel input barb. There were MAJOR bubbles at the head seal area and small bubbles at the fuel adjuster seal. Now we know what the problem is.

Did you just change your fuel filter or did this just happen? One of the most useful tools in my tool collection is a mity vac. They work great to prime fuel lines, test vacuum actuators and bleed brake lines among other things.

If you just changed your fuel filter fill the filter with fuel. If this just happened you probably have air getting into the fuel line, likely at the plastic T on top of the filter. Either the O rings are shot or the T is cracked.

Are you sure you have fuel in the tank? Absolutely sure?

The engine just wouldn't start one day with no changes made.

I just pulled a vac on the supply line and got fuel immediately. So we have an IP suction problem. I put a hose onto the suction line at the pump and blew into it and can hear air leaking out somewhere on the hard lines side. I'm guessing that means I need to reseal my IP?

777funk said:

The engine just wouldn't start one day with no changes made.

I just pulled a vac on the supply line and got fuel immediately. So we have an IP suction problem. I put a hose onto the suction line at the pump and blew into it and can hear air leaking out somewhere on the hard lines side. I'm guessing that means I need to reseal my IP?

Click to expand...

Ouch ... im guessing since u didn't mention it u haven't seen or noticed any leaks from the IP... mine was leaking and I could smell diesel in the cabin while driving .... if u do decide to tear into the IP to do the seals KNOW what ur doing and have a vagcom ready for adjusting the value back

777funk, try applying vacuum at the return discharge of your pump and see if it holds vacuum.

2nd check the fuel return.
I had same symptoms and had small leak in one of my lines between injectors

The fuel return does not hold vacuum. I put the vacuum tester on the return port at the pump and plugged the end of the fuel tank return line with my thumb. It doesn't even build vacuum, just drops almost as if pumped without being connected to anything.

bump. Have updated the first post with the following test results:

I can not pull a vacuum from the fuel return port (with my thumb on the fuel return line to cap it off). I can blow into the fuel supply port and hear it coming out near the area with the 4 fuel delivery valves.


Do I need a reseal?

777funk said:

bump. Have updated the first post with the following test results:

I can not pull a vacuum from the fuel return port (with my thumb on the fuel return line to cap it off). I can blow into the fuel supply port and hear it coming out near the area with the 4 fuel delivery valves.


Do I need a reseal?

Click to expand...

yes! If it cannot hold a vacuum, the seals in the IP are bad.

That's a bad leak if you can blow into the pump inlet and hear leakage near the delivery valves.

I can think of six places that can leak around there. The head seal, the big three sided plug and the cutoff solenoid, (these are low pressure while running, maybe 80ish psi) then there are the the four delivery valves, the four injector lines and the small center plug. These last three see injection pressure.

If you can hear the leaking you should be able to see it if you spray some soap solution around there.

No evidence of fuel leaking?

KLXD, there is no fuel leaking, but likely only because there is no fuel to leak. It won't prime and vacuum just leaks right out unfortunately.