No boost

I bought recently a Golf mk4 tdi with AJM PD engine I got it for a really nice price because it comes with a broken turbocharger.
I decided to upgrade the turbo with a GT1749VB with a mfs compressor wheel that I bought rebuilt from ebay, along the way I fitted some more upgrades like the PD150 intake manifold and physically removed the egr/asv valve.
I've installed everything and now have this issue that as soon as I connect the vacuum line to the turbo actuator it's like the motor itself starts to do a different noise it's like the vacuum pump is overloading the engine I try to run the car like this but nothing it struggles to reach 1500rpm its like it has a huge bottleneck and the motor can't breathe. If I disconnect the vacuum line engine sound comes to normal and the car is actually faster
I've double checked the vacuum lines to the N75 and it's free from error codes from the ECU. I really have no idea what it is causing this anyone here that has experienced this or could suggest anything to try out I would be extremely grateful.

im somewhat confused by your wording, do you mean that you got the car and put all these repairs and upgrades on it and NOW you are starting to drive it or you have been driving it as you do the upgrades?

Sorry about that.

First option, I bought the car made the repairs/upgrades and I'm now troubleshooting it.

SO, you have no idea what the timing is? what condition the engine internals are in?
I would start by checking timing marks.
Feels to me that your engine is not performing and has nothing to do with the turbo or vacuum.
Maybe valve leak?
Hard to say.
Do you have VCDS and a VAG-COM cable and a laptop? you need this.
How bad was the turbo damage when you got it?
There is a chance that the turbo failure dropped oil pressure and internal damage was done.

Don't want to scare you at all by this but when this rebuild i would go over the head and block first. Leak down test, Compression test, and so on.

I actually knew the owner of this car and it has very well documented history.

The turbo I've replaced was still the original turbocharger and it was leaking oil to the exhaust nothing major. Timing belt was changed 20k km's ago and it was running fine the engine itself it's pretty low "mileage" for the age.

Even a pretty worn out engine would go faster than this with some boost...that is what I'm trying to troubleshoot...the lack of boost.

I will try to make a video because my English it is pretty limited.

Here in the states any turbo purchased from ebay with the word rebuilt or reconditioned is suspect. Meaning its probably junk. That may not be true in europe.


You said it's like it can't breathe. Did you check the air box and intake pipes for obstructions? You didn't leave a rag or paper towel in the airway when you were replacing the intake did you?

Are you sure you routed your vacuum lines correctly?

Does it feel like it's driving in limp mode?

I recently swap a 1Z, deleted physically MAF/EGR. It felt like there was no boost, but it still ran. It wasn't until I had the ECU tuned by S&P that it felt normal.

My point is, you may have to tune the ECU before it runs properly.

Good luck

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jmodge said:

Are you sure you routed your vacuum lines correctly?

Click to expand...

I've routed my vacuum lines accordingly to this thread.

Corradoboy18 said:

Does it feel like it's driving in limp mode?

I recently swap a 1Z, deleted physically MAF/EGR. It felt like there was no boost, but it still ran. It wasn't until I had the ECU tuned by S&P that it felt normal.

My point is, you may have to tune the ECU before it runs properly.

Good luck

Click to expand...

It actually does feel exactlly like that but MAF is connected and throws no error,








So here is the video link

Sounds like engine loads up, I wonder if the turbo is seized and choking the exhaust. Is that possible? A boost and vacuum gauge might give you some insight to what is happening. There are two tests with vcds, one in basic settings and one in output tests, that run that system. One test with engine on and one with engine off. That would at least tell you if the ecu is sending proper commands. Put someone by the tailpipe when you plug that in, see what happens there

I will give that a try!

The turbo itself has a new core, there is only one thing on the back of my mind...I've replaced the compressor housing. This turbo had a chinesium compressor housing that I replaced with an original GT1749VB housing that was already modified to fit IC plumbing. I've taken some quick measurements at the time and they seem identical to me. But this turbo does have MFS compressor wheel.

I'm happy to report that this issue has been resolved, it turns out that it only needed an experienced Tdi mechanic

I'm kinda surprised how low the bar is set around here, I can't really forget that person who insisted on how I should check the timing...this is a PD engine for crying out loud.

Well it's the interweb, best we can do is guess.
What did the mechanic do to solve the problem?

smoking_gun said:

I'm kinda surprised how low the bar is set around here

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Yikes. I guess you should probably demand your money back.

Vince Waldon said:

Yikes. I guess you should probably demand your money back.

Click to expand...

smiley face - pile of sh!t - smoking gun

Heh... you complain about the misinformation, but you used vacuum diagram for an ALH.

...It's a PD, for crying out loud.

You know what they say when you are pointing fingers... three are pointing back at you.

The real issue is, you come looking for help, get it solved elsewhere and give NO RESOLUTION! That really sucks. You want to make the TDIClub a smarter place? SHARE WHAT WAS DONE FOR THE FIX.

In my opinion, swapping around turbo parts is a recipe for disaster.

We all will be watching for your future posts.

smoking_gun said:

I'm happy to report that this issue has been resolved, it turns out that it only needed an experienced Tdi mechanic
I'm kinda surprised how low the bar is set around here, I can't really forget that person who insisted on how I should check the timing...this is a PD engine for crying out loud.

Click to expand...

how is the bar soo lo?? he may have choppy posts, etc, but that one doesnt seem off in any way.
what was the fix? will it work?, idk.

Vince Waldon said:

Yikes. I guess you should probably demand your money back.

Click to expand...

heheh
isnt it in your sig what its worth, just the advice!
worth plenty. id say.

routed vac lines correctly as to a PD, if its a for cryin' out loud??

Turbo problem

Hi
I hope this is the correct thread for turbo problems?
I have a VW mk4 2002 AHF model.
My problem is turbo delay, the usual full boost has always been at 2000rpm.
Now I only get full boost at about 2500rpm, which is frustrating it changes the way of driving the car.
I have checked all vacuum pipes which is usually the probleem, already replaced them with stronger more reliable fuel pipes.
Checked turbo pipe for leak none found. I found a small leak on the vacuum pump sealed it still same problem. I cleaned my air intake sensor still no joy. I resently changed Cham shaft and valve guides so had to disconnect timing belt and changed water pump while it was striped. I have replaced and worked with the timing belt a lot of times so I doubt it is an timing issue as the engine runs and starts with no issues.
I must also say since the valve guide problem, before and after replacin, there is an sound around the turbo area of air escaping when the engine is switched off only for a short period and I'm still trying to find the location.
Sorry for the long post hope someone has some idea where to go next.
Thanx in advance.