NO BOOST? - 2003 VW Mk4 Golf Wagon 1.9 TDI

ValentineKilla

New member
Joined
Jun 27, 2020
Location
Cape Town, South Africa
TDI
2003 VW Mk4 Golf Wagon 1.9 TDI
Hey Guys,


I bought my first VW in January 2020.
Found an immaculate 2003 VW Mk4 Golf Wagon 1.9 TDI

Test drove it twice. Ran beautifully up to 140km/h. You'd never guess this was a high mileage vehicle. (347 000km)
It pushed you back in the seat in 1st and 2nd gear. Everything worked in this vehicle. So i purchased it.

THEN THE WORLD WIDE COVID-19 PANDEMIC BROKE OUT

I let her stand from February till about May, during the LOCKDOWN here in South Africa. As we couldn't transfer the vehicle into my name during the quarantine period.

In May 2020, I drove her to the fuel station to get some diesel and noticed she felt a bit sluggish.
So I headed to the freeway after filling up, only to discover there was NO BOOST at all, none what so ever! (Can still hear the turbo spooling)
I'm literally shifting into 5th gear before even reaching 90km/h. Changing gears at 3200RPM, flat foot, pedal to the metal. She's basically become a N/A Diesel???

- NO WARNING LIGHTS
- NO ERROR CODES


Doesn't appear to be in any form of Limp Mode, as you can rev her up without any problem. She's just extremely slow now. Motor is running fine and everything sounds good.

- NO EXCESSIVE SMOKE (Black or White) Almost Invisible.

I have since researched every forum, YouTube and TDI Facebook group I could find.

- I have replaced the vacuum lines. (Made No Difference)
- I have tried running her with the MAF sensor disconnected and reconnected. (Made No Difference)
- I have tried isolation the N75, also tried connecting it directly to the 12v battery. Tried switching the N75 and N18 around. (Made No Difference)
- I have tried removing the EGR, cleaned it up and refitted. (Made No Difference)
I can feel a bit of pressure from the plastic charge pipe, when the hose is off the EGR side.

My buddy and I have since resorted to removing the exhaust manifold to inspect the Turbo for Sticky Vanes.

- Cleaned out turbo exhaust housing. Everything looks fine. Reinstalled. (Made No Difference)

I'm completely baffled by this and am slowly going INSANE!!

Unfortunately I haven't been able to perform a vacuum test yet. But it all seems ok.

The latest thing I heard, is it could possibly be a blocked Catalytic Convertor?? I doubt it, as the car doesn't fart eggs or smoke badly.

Any ideas??? All feedback is greatly appreciated!
Thanks Guys & Girls...
 

KrashDH

Top Post Dawg
Joined
Dec 22, 2013
Location
Washington
TDI
2002 Golf
Did you use a mighty-vac to check the turbo vanes that they operate as they should in the vac tolerance allowed? How about adjustment?

Did you check your vacuum ball to be sure it's holding vac? It supplies the turbo and everything downstream.

Did you check the operation of your vacuum pump to be sure it's outputting the correct vacuum?
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
^this stuff^
The turbo actuator should move all the way over when the engine is started. If not you may be able to free it up just by exercising it. Or it might be rusted shut or has a hole in it.
 

Aaronh7

Member
Joined
Jan 18, 2020
Location
Illinois
TDI
2002 jetta ALH
Check and make sure you have vacuum to the n75. I just went through this on mine. The nipple coming off the vac pump is loose and not giving enough vacuum to the n75 to close the vanes

Sent from my SM-N950U using Tapatalk
 

Vince Waldon

Top Post Dawg
Joined
Apr 25, 2009
Location
Edmonton AB Canada
TDI
2001 ALH Jetta, 2003 ALH Wagon, 2005 BEW Wagon
Step 1: deep breath. :)

Step 2: follow the low power /limp mode thread listed in Bob's sig (and mine) step-by-step and you'll figure it out.

Step-by-step...skip no steps... leap to no conclusions...throw no parts at it. :)
 

KrashDH

Top Post Dawg
Joined
Dec 22, 2013
Location
Washington
TDI
2002 Golf
Check and make sure you have vacuum to the n75. I just went through this on mine. The nipple coming off the vac pump is loose and not giving enough vacuum to the n75 to close the vanes

Sent from my SM-N950U using Tapatalk
If it was directly off of your pump (ie not supplying enough vac) weren't your brakes acting up as well...?
 

BigAndy

Veteran Member
Joined
Apr 19, 2002
Location
Northern BC
TDI
99 A3
Step 2: follow the low power /limp mode thread listed in Bob's sig (and mine) step-by-step and you'll figure it out.
Step-by-step...skip no steps... leap to no conclusions...throw no parts at it. :)
What Vince said...and I quoted him so you get a chance to read it again. It ran fine before you parked it...so deep breath...then step one...then step two.
 

BigAndy

Veteran Member
Joined
Apr 19, 2002
Location
Northern BC
TDI
99 A3
Somethings to think about as you progress through the steps -- it's logical, you may have done some of the steps already...however it's logical...it's trouble shooting...we can fire suggestions all day long as to what went sideways. What with rodents, stale fuel, condensation in the tank, aliens...you get the picture.

One time I was driving home from the coast (Vancouver, BC) where it was balmy and warm...by the time I got to 100 Mile House, it was -35 C and the car would not go over 40 mph and then it would run for a bit then just stop...wait a few minutes it would start and I would get it going and idle in gear as far as I could go up this hill.

It turned out the filter was old, the fuel was non-winterized diesel and it was waxing up in the filter. Who knew, right? Now that's not your issue, I realize that, however that troubleshooting guide got me to the root cause.
 

flee

Veteran Member
Joined
Sep 19, 2011
Location
Chatsworth, CA
TDI
2002 Jetta GLS wagon
You can try wiggling the nipple coming off of the vacuum pump. Any wiggle is a leak.
You should also CLOSELY examine the brake booster's hard plastic hose for cracks.
These leaks can trigger limp mode before braking boost loss gets very noticeable.
 

Aaronh7

Member
Joined
Jan 18, 2020
Location
Illinois
TDI
2002 jetta ALH
If it was directly off of your pump (ie not supplying enough vac) weren't your brakes acting up as well...?
No brakes were still good I was getting about 9-12 at idle guess it was enough for the brakes

Sent from my SM-N950U using Tapatalk
 

KrashDH

Top Post Dawg
Joined
Dec 22, 2013
Location
Washington
TDI
2002 Golf
No brakes were still good I was getting about 9-12 at idle guess it was enough for the brakes

Sent from my SM-N950U using Tapatalk
Dang that's odd...when mine went it was taking about 45 sec to build vac but then it would be around 25...a good working pump the vac reading is almost instant. With those symptoms I would lose turbo and brakes after a pull or a couple brake pumps.
 

Powder Hound

Top Post Dawg
Joined
Oct 25, 1999
Location
Under a Bridge, Crestview, FL, USA
TDI
'00 Golf 4dr White 5sp, '02 Jettachero 5sp, Wife's '03 NB Platinum Gray auto(!)
Mine is doing much the same thing. Checked everything, and I mean, everything. A new fuel filter helped some, but I'll need some way to physically check the vane deflection. The actuator holds vacuum perfectly, the N75 works perfectly, and the vacuum lines are just fine. The only thing left, is that there is wear in the vane system inside the turbine housing, and thus the vanes aren't moving much in spite of the external lever moving its full range.

This situation has been a long gradual process; it didn't happen overnight. There were some errors recently encountered - I found an intake hose was not completely attached and that fixed the error, and shortly after that I found a worn strip in my intercooler that required a replacement. But after these fixes, it can hardly get out of its own way. Vane wear is about the only thing left for me that might fit what I'm seeing, which is basically a long slow response to boost request.

Cheers,

PH
 

Aaronh7

Member
Joined
Jan 18, 2020
Location
Illinois
TDI
2002 jetta ALH
You need at least 20 inches to pull the actuator full range.
Yes I have the vac nipple rigged for now till I can pull the pump currently getting 25 at idle. It still drops power off at 3k rpm but much better going to jb weld the vac this weekend and check the snow screen.

Sent from my SM-N950U using Tapatalk
 

KrashDH

Top Post Dawg
Joined
Dec 22, 2013
Location
Washington
TDI
2002 Golf
Yes I have the vac nipple rigged for now till I can pull the pump currently getting 25 at idle. It still drops power off at 3k rpm but much better going to jb weld the vac this weekend and check the snow screen.

Sent from my SM-N950U using Tapatalk
I was one of the unlucky ones that did the nipple fix (peened over the lip, tried high temp RTV, and THEN tried JB) to no avail. My pump was just worn to the point where the tolerances had worn out.
 

Aaronh7

Member
Joined
Jan 18, 2020
Location
Illinois
TDI
2002 jetta ALH
I was one of the unlucky ones that did the nipple fix (peened over the lip, tried high temp RTV, and THEN tried JB) to no avail. My pump was just worn to the point where the tolerances had worn out.
I hope that's not the case for me

Sent from my SM-N950U using Tapatalk
 

Black00Jetta

Veteran Member
Joined
Oct 15, 2003
Location
Relocated to AZ
TDI
2000 Jetta GLS Black 5spd
Replacing the vacuum pump is no that difficult. My pump ran around $80. The bracket on the bottom of the pump had to be bent to remove the bottom nut and bent back in place when done. Been working good for over a year
 

Aaronh7

Member
Joined
Jan 18, 2020
Location
Illinois
TDI
2002 jetta ALH
Replacing the vacuum pump is no that difficult. My pump ran around $80. The bracket on the bottom of the pump had to be bent to remove the bottom nut and bent back in place when done. Been working good for over a year
I figured they would be atleast a couple hundred dollars

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snakeye

Veteran Member
Joined
Dec 13, 2009
Location
Montreal, Canada
TDI
2003 Jetta and Wagon, GLS 5sp
1) check whether the actuator arm moves freely. If it does, then :

2) attach a t-fitting with vacuum gauge to the line from the N75 to the actuator and go for a drive. You should get 17 inHg at full boost, aka all the time until you rev the engine while driving, at which point it should lower to prevent overboost.
 

BigAndy

Veteran Member
Joined
Apr 19, 2002
Location
Northern BC
TDI
99 A3
The OP gave a lot of data in the first post and this thread got hijacked and they have never come back! Hopefully they got what they came for.
 

ValentineKilla

New member
Joined
Jun 27, 2020
Location
Cape Town, South Africa
TDI
2003 VW Mk4 Golf Wagon 1.9 TDI
Problem Solved - MAF

Turns out it was mostly the MAF sensor after all.

Clearly that "trick" of unplugging the MAF to check for boost, doesn't apply to this vehicle! Thanks guys
 
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