New to TDI need help trying to figure out a problem!

Hi, guys! I just purchased a 2000 Jetta TDI with a 5 speed. Now when I purchased the car, it had a condition where whenever you were in low revs you had no power until you stomped on the throttle and the car would take off! so I replaced the MAF sensor in hopes that this would help, as I unplugged the maf and had no problems except lower power of course. So fast forward to yesterday. I receive my new MAF sensor, install, and go for a drive. Car runs better than it has since i first got it, turbo works well and has plenty of power! get home, and pop the hood, and see one of the vaccum tees to my boost solenoid (pretty sure that's what it was) had broken! So I replace it then have to go to the store, and it starts sputtering in low revs from about 1K-2K bucking, sputtering and has no power. then once it gets to 2K it takes off and the turbo kicks in! It sometimes does it when in neutral as well, under no load. Now The timing belt and water pump was recently replaced, and timing was confirmed good at a shop with vcds. Cam is good, New air filter, and all vacuum lines were replaced. I've inserted a short video clip I took on the way to work this morning. I have no codes as well. Any suggestions are appreciated! Next on the list is testing the turbo actuator, as it does move, but I have no idea if it holds vacuum. Also a new fuel filter.
https://youtu.be/Zd__ljGfa0A

It sounds like you are on the right track. For the back yard mechanic I have found it easy to test the turbo actuator with a vacuum hose right off the vacuum pump straight to the actuator. With the engine running, pull the hose on and off the pump and feel with your hand the actuator move up and down smoothly for the full travel. Then after that is confirmed, pull the hose off the bottom of the actuator while you move the actuator down to its limit and put your thumb on the hose hole. The actuator should hold this position without leaking back up until you release your thumb.
To me it doesn't sound like a turbo or actuator problem as much as something is hooked up wrong or control valve is broken and not getting proper boost or air flow. Are you sure your hose goes to the turbo and not the egr or asv? Many get those confused as they learn these engines in the tangle of hoses in the same area.
The good thing about these cars is you can unhook all previous stuff mentioned and the car will still run. You can try pulling off the hoses to the egr and asv and see if that changes things in the trouble shooting process. Codes are only thrown when certain conditions are not met in the computer and some may take some driving to appear.
I would very carefully check the hose diagram as well for proper connections.

Was the MAF sensor a Bosch unit or aftermarket?
If not Bosch try putting the original one back in.
On the right side of the head is a vacuum pump for the power brakes and the vacuum controls.
Check if you are getting at least 20 inches of vacuum from it. The nipple going into the pump is usually a bit loose. Some fix it with epoxy or such.
The line you saw off at the broken tee should go to the top fitting of the solenoid and have vacuum, the fitting under it goes to the turbo actuator.

Hey guys! thanks for the help! It actually ended being resolved by replacing my N75 valve! I tried swapping it with the N18 valve and wouldn't you know it, we've got boost! Installed a new pierburg valve and all as well with the world and my TDI drives on! Thanks again!!!

I would still take a look at the turbo actuator to make sure it does not have a small leak that the N75 is coping with. That can produce a constant draft of dirt and actuator rust up through the N75 and on to the vacuum check valve to the vacuum pump. That could be the source of the trouble

JETaah said:

I would still take a look at the turbo actuator to make sure it does not have a small leak that the N75 is coping with. That can produce a constant draft of dirt and actuator rust up through the N75 and on to the vacuum check valve to the vacuum pump. That could be the source of the trouble

Click to expand...

Always smart to go over the entire sub-system when one component fails.