What is a "stock" ALH supposed to accelerate like?

I have never driven another ALH car, or any VNT car before owning this one.

I have a weird power band, its pretty late.. and laggy when shifting. I thought VNT's were supposed to be the almighty! lol (I understand it is likely not acting correctly..) Sometimes, I will drive 100 km (my drive to and from work) and have no boost at all, the car is a slug. I have verified with VCDS that when this is happening the ECU is requesting high boost, but the turbo is not providing. This is evidently seen with both the on board MAP as well as a mechanical gauge in the intake. Additionally, when it is doing its no boost thing it feels as though the vanes are wide open. It will reach 3500rpms and not have made any boost.. maybe 2psi.

I replaced the N75 today to be sure it wasn't just not doing what it was told. I have also tried just hooking the vacuum actuator of the turbo to straight vacuum so it will hold the vanes closed. And it is peppy around town, but 15psi down the hwy when it wants 0 at cruise and it throws limpmode.

SO now that we know the ECU is requesting the boost, the N75 has been replaced, and the vacuum source is good. I guess we must look at the turbo now. I did an N75 test with VCDS and could feel the turbo lever moving, but how far is it supposed to move?

I am unsure why it feels perfectly fine some days, and others.. it has no boost at all. I assume it should start making boost fairly early.. like 1300rpm?

The turbo actuator should move between 3to5ish to ~18.
How long have you had the car? Mileage? er Kilometerage?
How old and crunchy are your vacuum hoses?
How about getting under it, and verifying all the charge air pipes are clean and tight, including your intercooler. An oily intercooler is a sign of leaking (air and oil both).
The canonical thread:
http://forums.tdiclub.com/showthread.php?t=179589&highlight=diagnosing+limp+mode
Do a Ctrl+f on that page for the word 'intermittent'.

A stock ALH will have decent low end grunt. Peak torque is pretty flat from around 1800RPM? "Adequate" is a good description With my bone stock 315k mile 03 wagon, I can easily keep up with traffic under really any condition.

Go through the low power / limp mode threads. Each suspect part can be tested individually.

Turbo obviously isn't working correctly. A properly running ALH feels pretty peppy. Do a search here on fixing limp mode. Although you may not be getting a code and limp mode, the diagnosis and fix is the same.

I'd bet your turbo is the issue. Clogged vanes. How many km on car? I'm assuming your not the first owner. If previous owner drove the car like driving miss Daisy, the turbo never got a good workout and vanes are clogged.

Or vacuum lines. My 2003 is bone stock and it was doggy. Checked with VCDS and I had no boost. Replaced all the vacuum lines and now I have boost and yes it is adequate in traffic now.

STDOUBT said:

The turbo actuator should move between 3to5ish to ~18.
How long have you had the car? Mileage? er Kilometerage?
How old and crunchy are your vacuum hoses?
How about getting under it, and verifying all the charge air pipes are clean and tight, including your intercooler. An oily intercooler is a sign of leaking (air and oil both).
The canonical thread:
http://forums.tdiclub.com/showthread.php?t=179589&highlight=diagnosing+limp+mode
Do a Ctrl+f on that page for the word 'intermittent'.

Click to expand...

I have had the car since February. 290k kms. The EGR/anti-shudder is delelted, so the vacuum system is very minimal now. Everything seems okay, however I dont have a mightyvac to verify that the lines or actuator hold vacuum. I had the lower pipes off when I did the timing belt when I bout the car back in Feb. There is one of those connections under there that is oil soaked. I agree it is likely bleeding some boost, but I am fairly certain it is not causing any of my grief. The engine could have great low-mid-top end one drive and then the next be in limp with no boost at all. It is an Ontario car (read; saltiest winter place of the whole world..) so removing the turbo cartridge is a daunting task, to say the least.

Johhny04 said:

I'd bet your turbo is the issue. Clogged vanes. How many km on car? I'm assuming your not the first owner. If previous owner drove the car like driving miss Daisy, the turbo never got a good workout and vanes are clogged.

Click to expand...

290k kms, definitely not the first or even anywhere near the first owner.. lol the guy before me was some ****bag kid, so he likely drove whatever bag it had off of it.. LOL Just like me, foot on the floor ALWAYS. Although I am no ****bag.

I do have some doubt that it is the vanes though, because sometimes there is proper operation and the boost comes on and there is good low end in town. I think if it was the vanes, they would be stuck or limited to there throw and there would be pretty repeatable results.

The boost gauge is quite erratic when there is boost, It will spike 20psi and then drop itself right off to like 7psi and slowly build back up on the boost again.

I do believe I will get new vacuum lines and a new turbo actuator to rule them out.

Replace turbo actuator I've swapped 3 recently only firing check engine light when beat on for quite a while. They can work ok but not fully function. And while your doing it you can really feel the action of the vanes with it off the turbo.

Ontario. Is the splash shield missing? If so then I'd tend to put my money on what others are suggesting the problem as being the turbo actuator (they can get screwed up by the elements).

Replaced the turbo actuator with a new one today. Did it all from the topside of the car! Everything came undone easily, and with the actuator off the vanes move as freely as they possibly could. No drag whatsoever in their movement. The old can was full of rust and likely had a perforated diaphragm..

The car now drives properly, with greater low end torque than it has ever had. It really makes the straight pipe I did two weeks ago worthwhile now! Lol

Thanks for the help/advice my dudes. Another vw lives on.

Sweet!
Thanks for posting the solution

8v-of-fury said:

The old can was full of rust and likely had a perforated diaphragm..

The car now drives properly, with greater low end torque than it has ever had. It really makes the straight pipe I did two weeks ago worthwhile now! Lol

Thanks for the help/advice my dudes. Another vw lives on.

Click to expand...

There is a VW bulletin about the internal rust.

Glad you got it fixed & posted the resolution.
It may help others down the line.