ALH Low power around 3000rpm

[Mavrick]

2003 Jetta TDI Wagon
5 Speed converted

Drive ability is great if under 3000rpm and not pulling up hills. When it hits 3000rpm (or less if under load in 5th gear), MAF drops to 600-650ish and boost drops to 1400-1500mbar. If you keep it under WOT the boost and MAF come back around 3400rpm. I'm out of idea's as to what it could be besides maybe worn vane mechanism inside the turbo, but I haven't seen these symptoms before. Maybe ill try zip tying the ASV shut for a road test. Otherwise have gone through everything..

New timing belt, timing is bang on, advanced slightly
Removed snow screen and catalytic converter
New air filter, new fuel filter, pickup in tank is spotless and clean
Tried a couple different used MAF, N75, replaced vac lines
Vacuum pump is pulling a strong 30"
Vac actuator works well. Pulling at 5" and maxing at 20"
Vane lever is very free
Unplugged EGR for a road test, same results

Of course, no codes.

Any ideas?

 

[Powder Hound]

Has the intake manifold been cleaned lately?

Can you graph the throttle position sensor?

 

[mxracer291]

I have almost identical symptoms. I planned to clean my intake manifold soon to see if that would fix the issue! Keep this updated if you find something else. Thanks!

 

[UhOh]

My car struggled around 2,400. Cleaned intake manifold (etc.) and instantly became like new! Pretty much have to take off the EGR valve to get a good look at the status of the intake manifold: it's fairly easy.

 

[boertje]

Mavrick what nozzles are you running?

 

[Mavrick]

Stock engine. Forgot to add.. intake was not plugged but was replaced with a clean manifold "just in case."

TPS does not move from 100% when wide open, including when the power loss occurs.

 

[Vindiesel6]

I had a similar power loss issue above 3k rpm. It was traced to a boost leak at the MAP sensor port on top of the intercooler. Check for any oil residue at intercooler pipe connections too.

 

[mxracer291]

Here is a log graph of 2 pulls through my dead spot, looks too be like a sticky actuator or turbo vains!

Sent from my LGLS991 using Tapatalk

 

[bchaszar]

Hi there — this is a very old post, it wondering what ultimately fixed your problem, if anything? I’m having very similar symptoms. Dont have the tools/knowledge to run all the tests you ran….