IP return line lots of bubbles

Poofit

New member
Joined
Nov 16, 2020
Location
Brighton
TDI
1Y
Evening! Just put on a second hand injection pump after the other one failing. However, is it normal for lots of little air bubbles to come out of the return line? There is no air getting into the pump through the feed line. Doesn't seem to hold pressure using the mightyvac either. Could the pump be naffed?
 

tbones

Veteran Member
Joined
Dec 22, 2005
Location
Annapolis, Maryland
TDI
1996 Passat wagon tdi, 1991 Corrado TDI (sold)1983 Vanagon 7pass.GL 1.6td 1982 Westy;THE PHOENIX 1.6na(NOW JX/5speed) my partner's 2014 Jetta Sportwagon 6spd manual AND MY NEW TOY/PROJECT... Sunny, a bright yellow 87 syncro Westy with 1Z TDI motor
hi Poofit,

Is your newly installed pump running? I'd say get it timed and running and see if the bubbles disappear (mine finally did)

good luck with it!

Regards,
Steve
 

Poofit

New member
Joined
Nov 16, 2020
Location
Brighton
TDI
1Y
hi Poofit,

Is your newly installed pump running? I'd say get it timed and running and see if the bubbles disappear (mine finally did)

good luck with it!

Regards,
Steve
Thanks for the reply! It only runs if I keep pumping on the return line. I have the pump timed but doesnt like to run without me pumping. No matter how long I do it the bubbles just keep coming. I don't think this should happen :(
 

tbones

Veteran Member
Joined
Dec 22, 2005
Location
Annapolis, Maryland
TDI
1996 Passat wagon tdi, 1991 Corrado TDI (sold)1983 Vanagon 7pass.GL 1.6td 1982 Westy;THE PHOENIX 1.6na(NOW JX/5speed) my partner's 2014 Jetta Sportwagon 6spd manual AND MY NEW TOY/PROJECT... Sunny, a bright yellow 87 syncro Westy with 1Z TDI motor
Hmmm...

my logic thinking make me think there's a leak at the seal... is there any diesel leaking out anywhere?
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
Yeah, if you you're positive there's none going in and assuming it's completely bed it makes me suspect the shaft seal too. Every other seal sees pressure.
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
Foaming or bubbles in the return line means air getting in somewhere. If there's no bubbles in the supply to the IP but there is on the outbound that says that one or more seals on the new IP are bad and letting air get in.

What condition are the injector return lines to the IP? How long did this IP sit on the shelf or sit unused? Did this pump sit dry for a period of time?

If you're having to continually pump (as in vacuum pump?) on the return line to keep the car running then your IP will need to have new seals installed, there's too much air infiltration for it to maintain adequate fuel supply into the pump.

Steve
 

compu_85

Gadget Guy
Joined
Sep 29, 2003
Location
Springfield VA
TDI
... None :S
If you haven't redone the seals on the pump you just fitted, I'd suggest pulling it back off and replacing them now. At this point all VE pumps are getting long in the tooth, and the seals were leaking 5 years ago. Save yourself the trouble and do it on the bench!

-J
 

fatmobile

Veteran Member
Joined
Jul 16, 2019
Location
north iowa
TDI
an ALH M-TDI in a MK2, a 2000 Jetta
Sounds like a mainshaft seal.
Bad enough that some diesel might leak out from the seal too.
Behind that seal is hooked to the front of the pump so it's easier to pull in air than it is to pull fuel.
That seal can be changed with the pump on the car.
 
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