ALH sat for 3 years and now no boost. Vanes move freely and actuator moves and holds

QuantumRallySport

Veteran Member
Joined
Dec 15, 2009
Location
VA
TDI
mk2
Started right up. This is a VNT17/22 build in an MK2 chassis that has only been driven about 1200 miles and then sat in a nice dry garage on a battery tender for 3 years.

  • EGR and ASV delete.
  • Checked all the vacuum lines and boost piping.
  • Pulled vacuum on the actuator diaphragm and it moves as it should.
  • Actuator diaphragm holds vacuum no problem
  • Pulled compressor outlet and turbo spins no problem
  • I only get about 3-4psi of boost instead of the 25-26psi I should be getting.

Thoughts on what to look at next?
 

mr.loops

Veteran Member
Joined
Nov 24, 2010
Location
Kelowna
TDI
2002 jetta, 2003 Bora 1.8T
You said you checked vacuum hoses. Was this a visual check or did you put the vacuum gauge on them?


Sent from my iPhone using Tapatalk
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
Can you run VCDS n75 output test like an ALH?
 

csstevej

Top Post Dawg
Joined
Aug 12, 2004
Location
north nj
TDI
2001 golf tdi 4 door auto now a manual, mine, 2000 golf 2 door M/T son's,daughters 98 NB non-TDI 2.0, 2003 TDI NB for next daughter, head repaired and on road,gluten for punishment got another tdi 2001NB,another yellow tdi NB
How about checking the intake tract for mice nests or other blockage.
 

Growler

Got Soot Vendor
Joined
Nov 24, 2003
Location
Millersport, Ohio
TDI
Schmutz, 2015 Golf Sportwagen DSG & Schnurren, 2001 Golf GL 2 door 5M
Try unplugging the MAF and see if things improve. could be a bad maf reporting a stupid low airflow number. pulls the fuel, which nerfs the boost. easy to test with no VCDS, just unplug it and see if things improve.= on a quick test drive.
 

QuantumRallySport

Veteran Member
Joined
Dec 15, 2009
Location
VA
TDI
mk2
Try unplugging the MAF and see if things improve. could be a bad maf reporting a stupid low airflow number. pulls the fuel, which nerfs the boost. easy to test with no VCDS, just unplug it and see if things improve.= on a quick test drive.
I tried that first thing and it made no difference.
 

FJ40Jim

Veteran Member
Joined
Jan 2, 2002
Location
Lancaster, Ohio, USA
TDI
'01 Golf GLS 5MT, '12 JSW DSG
With engine idling, test for vacuum at the N75. A bad vac pump or leaky power brake hose can result in low/no vacuum to the N75. Tee in a vac gage or your mityvac to get a reading.
 

QuantumRallySport

Veteran Member
Joined
Dec 15, 2009
Location
VA
TDI
mk2
I just did some more quick troubleshooting. Looks like the N75 leaks when I apply vacuum to the upper port. Not sure if this is normal. I can get 20 inches of vacuum on my mityvac if I pump it quick but it leaks down in under 5 seconds.
 

Growler

Got Soot Vendor
Joined
Nov 24, 2003
Location
Millersport, Ohio
TDI
Schmutz, 2015 Golf Sportwagen DSG & Schnurren, 2001 Golf GL 2 door 5M
If you still have the black top EGR Valve from the original car you got your engine from, that is a suitable substitute for your N75 if you want to swap it in to test with. if things wake up and work, you know you just need another N75. Cheap Ebay purchase need not apply. get one form Idparts or Casgade german or Metalman...,
 
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