Economy - Longevity - Performance
The #1 Source of TDI Information on the Web!
Forums Articles Links Meets
Orders TDI Club Cards TDIFest 2016 Gone, but not forgotten VAG-Com List Unit Conversions TDIClub Chat Thank You

Go Back   TDIClub Forums > TDI Model Specific Discussions Areas > VW MKIV-A4 TDIs (VE and PD)

VW MKIV-A4 TDIs (VE and PD) This is a general discussion about A4/MkIV Jetta (99.5-~2005), Golf(99.5-2006), and New Beetle(98-2006). Both VE and PD engines are covered here.

Thread Tools
Old June 15th, 2018, 08:44   #16
Join Date: May 2017
Location: Manitoba
TDI(s): Golf ALH

JRmonster huge help.

It's stock auto.

So sounds like I had open/closed terminology mixed up.

So at idle max closed vanes on auto we're looking for 14" out of N75? Please confirm I'm understanding that correct.

So if only 14" expected out of N75, that would say N75 is working correctly. Please confirm I'm understanding correctly Jeff. Thanks!
AceTdi is offline   Reply With Quote
Old June 15th, 2018, 13:36   #17
Veteran Member
AndyBees's Avatar
Join Date: May 2003
Location: Southeast Kentucky

For what it is worth, I believe you will see the actuator pull the arm down solidly against the set screw when the engine is fired up (idle). At least that is my observation on the ALH engine in my 84 Vanagon........... and, it works just fine!
'84 Vanagon '02 ALH TDI engine Malone Stage 1 tune. CAT, SS 2" exhaust, E-vac system, DMF with upgrade pilot shaft, 4.57 R&P, fan assisted IC. (32 to 35+ MPGs consistently)
AndyBees is offline   Reply With Quote
Old June 15th, 2018, 14:03   #18
Join Date: May 2017
Location: Manitoba
TDI(s): Golf ALH

Great news guys. Did swapnostics with N75 and N18 as BobOH, Enabled, JRMonster suggested.

With N18 in place of N75, vacuum outputs (MightyVac tied with Tee fitting into N75 out to turbo while driving), I got between 13-15in/hg at idle/non-vane demand.

On vane demand got full 18in/hg of vacuum. Most importantly no underboost. Proper turbo function.

(Old/failed N75 was 10in idle, max 14-15in on vane demand. Not enough to fully move vanes, which require 18in to actuate)

This points with 99% certainty to failed N75 which I will now replace confidently.

Thanks for the suggestion there. Sorry if a few got offended by my very focused question.

Been fixing long enough to know diagnosis MUST confirm part failure with absolute certainty (multiple methods if in question), before replacing parts. Throwing parts is not pragmatic.

Hopefully this helps a few people who haven't used this diagnostic process on N75 before (I hadn't seen info). Will try to post results after new N75 arrives for extra confirmation, but as you know sometimes when it's fixed it's forgotten. Thanks again all.

Last edited by AceTdi; June 15th, 2018 at 14:07.
AceTdi is offline   Reply With Quote
Old June 16th, 2018, 13:02   #19
Veteran Member
Join Date: Aug 2008
Location: Reno, sort of...

We are always here to help, and sometimes we all get a bit testy when suggestions aren't followed after being asked for. I have been a member of this website for a long time, and I still run across stuff I need help with. OP, thank you for letting us know you found the problem.
2001 Jetta GL TDI, Tinted, Ventectomy, Catectomy, EGR-ectomy, TDTuning, HIFLO .216's, Stealth 17/56 Garrett, VCDS Hex+CAN, South Bend Daily Driver 2 Clutch, DG Short Shifter, Previous Diesel: 1983 Rabbit Diesel
Nevada_TDI is offline   Reply With Quote
Old June 19th, 2018, 12:18   #20
Veteran Member
Join Date: Oct 2011
Location: Monroe, NY, USA

Originally Posted by AceTdi View Post
(Old/failed N75 was 10in idle, max 14-15in on vane demand. Not enough to fully move vanes, which require 18in to actuate)
Mine is about 10 inches or so.
Sounds like your making headway.
Bottom port on both of those valves should run to a tee that goes to the bottom of the air filter box. Does yours?
Make sure the hole in the filter box is clear.
wonneber is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
No boost...can't solve by addressing VNT actuator, N75, vacuum vtamb81 VW MKIV-A4 TDIs (VE and PD) 13 June 15th, 2015 23:21
What gives the N75 it's output signal? Gruni14 VW MKIV-A4 TDIs (VE and PD) 19 October 12th, 2014 22:57
Idle Fuel Consumption w/ Max Alternator Output philngrayce TDI 101 18 May 4th, 2013 14:18
Vacuum output from N75 to VNT csstevej TDI 101 1 January 13th, 2012 06:36
what determines the torque and max power output? weichsand TDI 101 5 March 31st, 2004 09:33

All times are GMT -7. The time now is 19:34.

Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright - TDIClub Online LTD - 2017
Contact Us | Privacy Statement | Forum Rules | Disclaimer
TDIClub Online Ltd (TDIClub.com) is not affiliated with the VWoA or VWAG and is supported by contributions from viewers like you.
1996 - 2017, All Rights Reserved
Page generated in 0.09117 seconds with 12 queries
[Output: 71.30 Kb. compressed to 63.23 Kb. by saving 8.06 Kb. (11.31%)]