reduced power

oldbird1965

Veteran Member
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Oct 29, 2006
Location
Arizona
TDI
Black 98 NB, Silver 06 NB, White 98 NB Green 02 NB Silver 03 NB
Hi, last year I was in limp mode on the 1998 Beetle so replaced the N75 and all the vacuum hoses. Ran great after but now its doing it again. The code is 00575 17-10, not sure what to do next. Replace the Map? I read something about a pressure unit for turbo? Also read about a O2 sensor, didn't even know there was one? I have had the Vag-Com for years but really don't know how to use it that well. Any suggestions? Thanks, Glenn
 

oldbird1965

Veteran Member
Joined
Oct 29, 2006
Location
Arizona
TDI
Black 98 NB, Silver 06 NB, White 98 NB Green 02 NB Silver 03 NB
I don't have a gauge but I'm sure its underboost, there isn't any black smoke anyway. What does both of these mean from your link?

  • Check Basic Setting > MVB 011

  • Check Pressure Unit for Turbo Charger
The motor has 150K on it, about 100K ago I took off the intake manifold and cleaned it. I don't want to do that again for sure. I'll check and clean rust scale off wastegate/actuator. Isn't there a way for Vag-Com to check stuff out? Thanks, P2B!
 

AndyBees

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Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
Your engine doesn't have a O2 Sensor.

(Caution BE SAFE)
If you can place your NB on Jack Stands high enough to slide under and observe the Turbo Actuator, you can watch it pull down solid against the Set-screw when the engine is first started. You have to be looking at it when the engine is started.

A properly functioning Actuator will move Up and Down in its entire range of motion.... Up with the engine off and Down with it idling. Of course, this is depending on what's going on inside the Turbo Variable Nozzle assembly. If it is corroded, loaded with soot, rust, etc., well, it could be stuck in position or have very limited movement.

The Vacuum pulls down the Actuator in Full Boost position at Idle. Pushing on the accelerator under load results in the N75 releasing Vacuum to provide the requested Boost. It operates opposite what you might think. The Spring in the Actuator is much faster than the Vacuum. So, releasing Vacuum gets the job done faster, by design. Letting up on the Throttle or as the ECU reduces boost demand results in the N75 releasing more vacuum until the Vanes inside the Turbo are basically shooting the Exhaust gases at almost a 90 degree angle to the Turbine blades which reduces its speed and obviously boost. Then, if you stomp on the accelerator, the N75 applies Vacuum to pull the Actuator down which moves the Vanes in a steeper angle to speed up the Turbine (increase Boost). Sometimes the lag in the Turbo boost is because of the Vacuum catching up with demand as well as the hot burning Exhaust gases doing their part.

Side note: The VNT Turbo does not have an internal by-pass. The angle of the Vanes is what determines boost which is controlled by the ECU via the N75, based on Accelerator demand.

Here is a good Video showing the disassembly of a VNT15 off an ALH TDI engine. The guy does a fairly good job explaining everything including doing logs VCDS to see what the demand is vs what the Turbo is actually doing.

 

P2B

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Jan 11, 2006
Location
Toronto & Muskoka, Canada
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2002 Jetta, 2003 Jetta, 2003 Jetta Wagon
If you can place your NB on Jack Stands high enough to slide under and observe the Turbo Actuator, you can watch it pull down solid against the Set-screw when the engine is first started. You have to be looking at it when the engine is started.
OP has VCDS so is better served by using the actuator test function, which doesn't require a helper to start the car and, more importantly, allows observation of actuator travel in both directions.
 

AndyBees

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Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
OP has VCDS so is better served by using the actuator test function, which doesn't require a helper to start the car and, more importantly, allows observation of actuator travel in both directions.
And, that's why I linked the Video which also provides very good educational info as well as the use of VCDS for testing actuator, mapping boost, etc., and, I knew he has VCDS!
 

oldbird1965

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Oct 29, 2006
Location
Arizona
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Black 98 NB, Silver 06 NB, White 98 NB Green 02 NB Silver 03 NB
Thanks guys, that's great information. Now I have to find the time to check it out. I'll get back as soon as I can. Thanks
 

oldbird1965

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Oct 29, 2006
Location
Arizona
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Black 98 NB, Silver 06 NB, White 98 NB Green 02 NB Silver 03 NB
Actuator rod was up with engine off and down with it running. Put a mity-vac on the actuator itself and got what looked like good movement. With the VCDS it failed the output test for the N75, looks like that's what I have to do is replace it again. Only lasted a year? I got it from IDparts, is there a better source then them for parts? All the vacuum lines looked good and attached. Went for a short ride and it brakes OK telling me the Vac pump is working. Again, thanks for that info to get me this far!
 

P2B

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Location
Toronto & Muskoka, Canada
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2002 Jetta, 2003 Jetta, 2003 Jetta Wagon
Actuator rod was up with engine off and down with it running. Put a mity-vac on the actuator itself and got what looked like good movement. With the VCDS it failed the output test for the N75, looks like that's what I have to do is replace it again. Only lasted a year?
If the actuator moved when you started the engine, the N75 is working. What do you mean by "failed the output test for the N75" ? Did you run the boost control system test as shown in the video I linked?
 

oldbird1965

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Black 98 NB, Silver 06 NB, White 98 NB Green 02 NB Silver 03 NB
I'm referring to the test on the 'other' linked YouTube inbetween 5 minutes and 8 minutes. On the YouTube you linked I don't understand how you test the boost control system by selecting group 11 under basic settings? Just select group 11 and it will just move the rod back and forth? I got rained out and tomorrow I'll have my wife start the engine while I watch the actuator rod. Thanks
 

P2B

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Toronto & Muskoka, Canada
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2002 Jetta, 2003 Jetta, 2003 Jetta Wagon
I'm referring to the test on the 'other' linked YouTube inbetween 5 minutes and 8 minutes
Right, but what failure did you observe?
On the YouTube you linked I don't understand how you test the boost control system by selecting group 11 under basic settings? Just select group 11 and it will just move the rod back and forth?
Yes, in basic settings select group 11 and click Go.
 

oldbird1965

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Oct 29, 2006
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Black 98 NB, Silver 06 NB, White 98 NB Green 02 NB Silver 03 NB
I did not get any needle movement on the mity-vac, the needle just stayed on Zero! I assumed that was a failure.

OK, ok, I admit it, I'm an idiot! lol I didn't click Go! I hope its not a timed test to give me enough time to get under there to watch the actuator rod.

Thanks for putting up with me, maybe I'm just lucky but having vag-com and not using it that much indicates that my five bugs have always worked pretty good.
 

P2B

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Joined
Jan 11, 2006
Location
Toronto & Muskoka, Canada
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2002 Jetta, 2003 Jetta, 2003 Jetta Wagon
I did not get any needle movement on the mity-vac, the needle just stayed on Zero! I assumed that was a failure.
I would assume a vacuum leak such that there was nothing remaining in the reservoir when you ran the test. I don't consider the N75 output test particularly useful because it relies on residual vacuum after the N108 test shuts off the engine.

Have you checked how much vacuum is applied to the N75 input at idle? Should be at least 22in/Hg (and preferably closer to 28), if not you have a leak or a weak vacuum pump.
OK, ok, I admit it, I'm an idiot! lol I didn't click Go! I hope its not a timed test to give me enough time to get under there to watch the actuator rod.
The test will continue to cycle the actuator rod until you stop it. I've been known to leave it running for extended periods in an effort to improve sticky spots in the actuator travel.
 

oldbird1965

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Oct 29, 2006
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Arizona
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Black 98 NB, Silver 06 NB, White 98 NB Green 02 NB Silver 03 NB
Started the day looking for my vacuum gauge and couldn't find it so I checked vacuum with my mity-vac. Only got 16 in but don't know how good the mity-vac is? Got under the car and had my wife start it and turn it off twice, the actuator rod never moved. I don't know why I said different the other day? Rechecked all vac lines, they are good I think. Then I was going to do the group 11 test and had to drop my tools and do a honey do! Will do that tomorrow. My feeling now is I have a weak vac pump, I took the reading off the T on the big line that runs to the brake booster, maybe that's the wrong spot to check vac? Is there a vac line diagram any where so I can double check all the lines to make sure they are connected the right way? Thanks!
 

AndyBees

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Location
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Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
The small nipple on the check-valve on the big pipe coming off the vacuum pump provides vacuum to everything that's connected to all those vacuum operated devices there on the back of the firewall. So, yes, that would be the best place to test the pump. I've had to replace that black plastic pipe on a few vehicles because of a splint along the end next to where the fitting plugs into the brake booster.

Yeah, if you are questioning in your mind the possibility the vacuum hoses may not be connected properly, you need a diagram or another vehicle sitting beside yours to use for reference. There is a Y with three vacuum hoses connected to it. I've found one or more of those pulled loose enough to cause a vacuum leak.

Yep! The Actuator Rod is suppose to pull down solid against the set screw seconds after the engine is fired-up.

Find that vacuum gauge. It's your view into what's going on.
 

oldbird1965

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Black 98 NB, Silver 06 NB, White 98 NB Green 02 NB Silver 03 NB
Thanks P2B, in your post you mentioned up to 26 vac and I only had 16 so started thinking that I'm losing vac somewhere (like you said) so I checked all the vac lines again with that diagram you gave me. They are all connected right and tight but when Andy said something about the brake booster line cracking I took it off to take a look. Yep, cracked! Thanks Andy for that suggestion! Now I need to order parts, I'm going to get a check valve and the brake booster line just to be sure. I didn't really like the way the nipple looked on the check valve.

I have ordered parts from IDparts before, where do you guys shop for parts? Thanks again!
 

AndyBees

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Joined
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Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
I use Autohausaz, Marquette Automotive (Metalman), German Cascade, Idparts, and there may be others. Those last three are registered vendors here in the TDI Club. I did order one of the hard pipes from the vacuum pump to the booster from eBay, mostly because it was the only thing I needed at the time . It has functioned fine for a little over a year.

Side note:
I have a vacuum leak in the vacuum system of the ALH enigne that I installed in my Vanagon. I've narrowed it down somewhat. I have a dash mounted vacuum gauge. It has never read higher than 23 inches. I just assumed that was tops for the typical ALH vacuum pump (I had never bothered to look-up the specs.) Well, about a month ago, I was trying to find the leak. In a process of elimination, I started by connecting my Air Condition System Vacuum Pump directly to the vacuum pipe that goes to the gauge at the dash of the Van. Well, it never pulled no more than 23 inches. Then, I connected a hose directly to the back of the gauge, 23 inches. So, obviously, the gauge is faulty. Then I connected my AC Vacuum Pump to my hand held vacuum gauge and got 29.9 inches almost immediately. That's sort of why I was suggesting that you find your lost vacuum gauge. I hope to continue looking for the leak later this week.
 

oldbird1965

Veteran Member
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Oct 29, 2006
Location
Arizona
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Black 98 NB, Silver 06 NB, White 98 NB Green 02 NB Silver 03 NB
ALH in a Vanagon, that's pretty cool! Does the motor pull the Van pretty good? I hear ya, finding a vac leak is not easy sometimes. Its not like the opposite, spray a soapy solution on a tire to find a leak. Its no fun waiting on parts, I went ahead and ordered it thru IDparts last night and I haven't gotten a email yet if they have shipped it. Oh well, I"ve got other cars to drive.

Another side note:
In the late 90's I bought a Lesharo 20' motorhome with a blown 4 cylinder motor and put a GM 3.8 V6 supercharged motor in it out of a Pontiac Bonneville. Wiring was the worst headache but that thing ran great, took it to Alaska! I'll get back to this thread when I get the parts, Thanks for you help!
 

AndyBees

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Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
@oldbird1965

Yep, chasing down a vacuum leak can be a challenge for sure. (Keep us posted)

So ironic! Wow! I come extremely close buying a 1984 Lesharo in 2007 when I bought the Vanagon. However, it had been my intent to build a TDI Vanagon for several years. I knew it would be a lot of work and it was considering I went full blow eTDI just like in the Jetta. So, a Lesharo was sort of plan B. And, driving to Alaska was the goal. At that point, I had driven an '83 Vanagon with the 2.0 Air-cool engine to Alaska 7 times from 1986 to 2003.

Anyway, I did drive the 84 with the ALH engine to Alaska in 2014 & 16 pulling a popup camper. It ran flawlessly each trip.

Below is a link to my build project which was started in 2010. It is very long (please don't post in it).

Below is a link to the 2014 road trip to Alaska.

Below is a link to the 2016 road trip to Alaska.
 

oldbird1965

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Oct 29, 2006
Location
Arizona
TDI
Black 98 NB, Silver 06 NB, White 98 NB Green 02 NB Silver 03 NB
WOW! is all I can say. Your conversion and trips are amazing Andy! I wish I had documented my rebuild like you did. I don't even know where the pictures are, lol. We are not at home now to even look for them. Winters in AZ and on the road with our 97 F350 dually PSD and 36' 5er for the summer. I have my 5 TDI Beetles all over the country to use when we get there. They sit for 10 to 11 months and always fire right up when we go to use them. Glenn
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
@oldbird1965

Wow! That is the life. During our travels down through the years, we've stumbled onto some folks doing basically the same as you. They had vehicles in various places to use when they got there.

Well, I chose to not do a Westy Vanagon mainly for the same reason. In the 83 Vanagon with the Air-cool engine, we took a big tent. We hit the campgrounds and an occasional motel, depending on circumstances. With the 84, pulling the camper is easy. It doesn't seem to test the engine's ability to handle the extra 1500 lbs (that's the weight of our new one). We can set-up camp and then "bobtail" around with the Vanagon.

Anyway, if I can iron out all the bugs over the next few weeks, we're going to do one more long road trip. We'll either be going back to Alaska or the northeast to New Brunswick, Canada and Nova Scotia. We went there in 2013 with the Vanagon after the TDIFest at Bethel, Maine... fun times.

Sorry to high-jack your Thread. Keep us posted.
 

oldbird1965

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Oct 29, 2006
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Black 98 NB, Silver 06 NB, White 98 NB Green 02 NB Silver 03 NB
Your not high-jacking, we are BSing! About ten years ago we pulled a 1993 Geo Tracker behind the 5er a couple years but that was just to nerve racking for me. I was 65 foot long and under the laws for triple towing many states had a limit of 65' with WY being the only exception at 75'. I got trapped a couple times in spots and had to cut off the Geo to get out. I just said enough of that and started buying some 'cheap' TDI's. The 98 I'm working on now I bought new, the rest used. Glenn
 
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