Air bubbles in lines, 2003 jetta wagon, auto, 229,000miles

[rustybolts]

Installed an IV line above the injection pump and return line below the pump! After vacuum return line and bleeding injectors, it started right away and ran for 1 or 2 minutes, then died ! Right after it died, i saw lots of air bubbles coming from the supply line and up to the IV container. Check and double-check both lines and clamps for leaks, including return line from injectors, couldn't find any! Outside of injection pump not leaking at all, not from the top gasket or the QA gasket , and the head seal is not leaking either , Just wondering if the Diesel Geek pump seal will solve this inside leak or there is other trouble in the injection pump? Already change filter and o'rings, but bypassed it to eliminate them. Original IP and never open. Is it time for a rebuilt pump?

 

[Genesis]

Check the thermal T, it's O-rings and the fuel filter and where the "T" sits in the filter. If that fit is not snug in the hole of the filter it will leak, and a very slightly out-of-round hole in said filter will leak too. The odds are VERY good that's where the air is getting in.

 

[BobnOH]

Yes, with no sign of leakage at the pump, it is the last thing to check.

 

[KLXD]

My understanding here is that you're running off a bottle with the filter bypassed so the filter tee is out of the picture. Ran for a bit and quit. Did you try sucking on the return line again and restarting? Might not have been a complete bleeding job if you're lucky.

All the seals on the pump are pressurized while running so they might leak out but not cause it to die except the shaft seal which sees the low side of the pump but I wouldn't think it would leak enough to cause it to die and you'd see air going through on the return side while it did run. But I don't know why it didn't leak while you were vacuuming.

A little more background on why you're running like this would be of interest. You say you've taken the filter out of the picher to exonerate it. So I assume you're having starting problems due to air.

This sounds familiar. Do you have another thread on this problem?

 

[rustybolts]

Tks, KLXD, for helping diagnosing the problem. Will recheck again all lines connections( 3rd/4th times) and redo an IV test with the return line above the pump this time to look for air bubbles! Might plug or block return line from injectors to eliminate that .
! Do you think doing a Diesel Geek reseal might help or solve that? Spend more time watching videos than do the work , excellent videos! But since the pump is not leaking on the outside, wonder if this will create more chance of problem, should not! Will do the IV test and report, making sure i have enough diesel in the bottle, found out the pump only use 20/30% of fuel and letting the rest go to the return container! Just trying to eliminate injection pump, don't need that on my Xmas wish list ! Tks

 

[fatmobile]

So you have a container you are pulling fuel from and then returning fuel to?
Is that what you mean by IV?
I usually refer to that as bottle feeding.
A little confused by the return line below and above.
Air coming from the front of the pump after shutoff usually means it's a bad mainshaft seal.
The area behind the mainshaft seal is plumbed directly to the front of the pump.
Pretty easy fix with the pump on the car.
But the belt needs pulled, along with the sprocket and hub.

You will probably need a dial gauge like those used on the old 1.6D
to see where the hub is set before you pull it.
So you can put it back to the same place.

 

[rustybolts]

Tks for giving a direction toward the head seal ! Was thinking of head seal replacement in first place and waiting for Dieselgeek kit to arrive . Will install and let you know if that works !

 

[KLXD]

Tks, KLXD, for helping diagnosing the problem. Will recheck again all lines connections( 3rd/4th times) and redo an IV test with the return line above the pump this time to look for air bubbles! Might plug or block return line from injectors to eliminate that .
! Do you think doing a Diesel Geek reseal might help or solve that? Spend more time watching videos than do the work , excellent videos! But since the pump is not leaking on the outside, wonder if this will create more chance of problem, should not! Will do the IV test and report, making sure i have enough diesel in the bottle, found out the pump only use 20/30% of fuel and letting the rest go to the return container! Just trying to eliminate injection pump, don't need that on my Xmas wish list ! Tks

I don't think the seal kit includes the shaft seal. I don't think the head seal or the QA seals are the problem since they are pressurized while it's running. To around 100ish psi. They can let air in when it's stopped but not while running and if you have the fuel supply above the engine and the return line submerged in it they shouldn't let air in even then though you didn't say you were going to change other than the head seal.

Also, changing the QA seals will mess with the IQ which might cause you more problems.

 

[fatmobile]

Right, not a head seal
a mainshaft seal leak.
The seal around the spinning shaft.