lost boost

Tristan210403

Member
Joined
Nov 22, 2020
Location
Virginia
TDI
Mk4 jetta tdi
so basically i was driving along and heard a sound then lost all boost, i drove along to a gas station because i was already low filled up and then my boost was back. i’m extremely confused, any advice?
 

Tdijarhead

Top Post Dawg
Joined
Nov 10, 2013
Location
Lawrenceville PA
TDI
2003 TDI Jetta Daughters Car, 2001 TDI Beetle, Wife’s car, 2005 Golf TDI Mine, all 5 spds
Any black smoke coming out your tail pipe? It sounds like you blew a boost hose, check all the intercooler/turbo piping. I’m not sure why the boost would come back unless your car went in limp mode and reset after you shut it off to fill up.
 

Tristan210403

Member
Joined
Nov 22, 2020
Location
Virginia
TDI
Mk4 jetta tdi
Any black smoke coming out your tail pipe? It sounds like you blew a boost hose, check all the intercooler/turbo piping. I’m not sure why the boost would come back unless your car went in limp mode and reset after you shut it off to fill up.
there was no black smoke, my dad said he saw puffs of blue smoke from time to time but not constant while i was limping to the gas station. it’s extremely weird and it’s got him confused all the way too because the boost came back
 

Vince Waldon

Top Post Dawg
Joined
Apr 25, 2009
Location
Edmonton AB Canada
TDI
2001 ALH Jetta, 2003 ALH Wagon, 2005 BEW Wagon
"Limp mode" is the search term you are looking for. :) The ECU senses a boost issue and shuts down the turbo to protect it from damage. Toggling the power makes the ECU forget its opinion of the turbo and the power is back.

Lots of possible causes... a thorough scan with a VW-specific scanner like VCDS is a very good start. There's an excellent step-by-step troubleshooting guide listed in my sig to get you started.
 

Tristan210403

Member
Joined
Nov 22, 2020
Location
Virginia
TDI
Mk4 jetta tdi
"Limp mode" is the search term you are looking for. :) The ECU senses a boost issue and shuts down the turbo to protect it from damage. Toggling the power makes the ECU forget its opinion of the turbo and the power is back.

Lots of possible causes... a thorough scan with a VW-specific scanner like VCDS is a very good start. There's an excellent step-by-step troubleshooting guide listed in my sig to get you started.
ah, that does make a lot of sense. we have vcds so tomorrow we’ll look at it and see what’s going on. thanks for all the help!
 

Tristan210403

Member
Joined
Nov 22, 2020
Location
Virginia
TDI
Mk4 jetta tdi
If you have a 2004 jetta you probably have the usual BEW boost hose tab wear which causes boost hose to pop off. On restart the ecu "resets" you'll have some boost but most will leak out and put you back into limp mode. You can get a kit called "BEW doggie collar" sold by vendors and on websites.
i have the 2001 1.9 ALH, does this still apply?
 
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