building boost slowly

[SlowDr1v3r]

so yesterday did a few pulls just having some fun in the car. drove the car today and was sitting in traffic and driving local for about an hour and a half. on my way home i noticed the car felt a little sluggish. i hit full boost but takes long to get there even in higher rpms. not even hitting full boost in the higher gears. been searching to see if anyone has had these types of issues but everyone has totally different things. just started before work so i havent gotten a chance to check anything but wanna check the basic stuff first. hopefully its something easy to take car of. car has a chip and and exhaust thats it. any advice on what i should start off with? sounds the same as it did yesterday so im 90% sure there`s no leak before the turbo. maybe a wastegate issue? thanks guys.

[-Billy]

My best guess is you're correct about the wastegate issue. I had a nut back off one of the wastegate actuators before and it did pretty much exactly what you're describing. It made like 17-18 pounds of boost instead of the normal 23ish iirc, and got there noticeably slower.

[SlowDr1v3r]

definitely have to check that. but i dont have access to a compressor to do a pressure test. i can kind of hear a hissing when boosting but doesnt sound like an exhaust leak. more like an external wastegate. and its weird because im hitting full boost just harder to get there. just hoping its not a bad turbo.

[-Billy]

If it is, in fact, what I'm suggesting, it can be varified visually. It's real tight down there, but when I had that problem I stuffed my phone down there on video and could easily tell that the wastegate actuator nut was completely missing on the passenger side turbo.

[SlowDr1v3r]

Will definitely check that in the morning and make sure the intercooler piping is all on and tight

[SlowDr1v3r]

Waste gates are fine from what I see. Went under the car had a friend Rev it and no leaks around the turbo. Just at the vband where the downpipe connects to the exhaust. Im leaning more towards a boost leak somewhere. Or maybe n75 but it's not throwing a code. Not even a soft code. Another other ideas?

[SlowDr1v3r]

So disconnected the n75 to see if it would spool faster to see it there was an issue with it and when I did, the car didn't pass 6psi. In any gear at any throttle.

[SlowDr1v3r]

Anyone got any other suggestions?

[vavJETTAw36]

Check your diverter valves. Easy way to check is pull the vacuum lines off and plug with tape or something. Had the same issue a couple weeks ago. Should see more boost If that's the case.

Have you verified the ecu is requesting the amount boost you are looking for?


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[SlowDr1v3r]

How do I check that? And now I'm getting a code 17964 - charge pressure control negative deviation. Sporadic. Checked the diverter valves and one of them has a bad o ring. So gonna look for a new set. Have an aftermarket tbb but gonna change it anyway because doesn't look like it's in the best condition. Still haven't gotten a chance to pressure test though. Only smoke machine. Didnt see anything there.

[SlowDr1v3r]

Would a bad n75 valve cause boost to rise slowly? Don't wanna spend the 120$ for no reason. Part throttle then wot and it builds boost a little quicker and stays at full boost. Just wot throws the code and goes into what seems limp mode because it won't pass 4psi. But I really think I hear a hissing noise. This car is really f'ing me on purpose lol

[vavJETTAw36]

Do you have vag com? You can also check it with an eBay cable (15 bucks or so)


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[SlowDr1v3r]

i have vag 401. Like a vag com knock off but all the same features so i guess i`d be able to. Any links to the procedure by any chance? and just a little update changed the n75 and pressure tested the car. one of the couplers was leaking. Dont know if it was the clamp or coupler itself but changed both. also have a slight leak from on of the diverter valves. Gonna borrow a friends set today and see how that goes. Can`t think of anything else at the moment to check. Will post results later.

[christianb5s4]

Your 6psi from unplugging the N75 is normal, because the boost you will see will only be wastegate pressure which on K03s/K04s, the wastegates are typically set around 6-8psi from factory. Definitely swap diverter valves and see what happens.

[SlowDr1v3r]

Finally figured it out. It was a little hard since a few things went bad at the same time. After getting that charge pressure control code i ordered a new n75 and code went away. Pressure tested the car and had a leak on one of the y pipe hoses. Fixed that. After changing that and a vacuum line that was leaking i was still have the issue. Everyone was saying my car was really quiet but i didn`t really think anything of it because i had just fixed my vband that had broken. But the next day i hear a rattling from the muffler and notice a piece of the inside that holds the packing was rattling around in there and all the packing was there blocking the muffler. Changed it to a vibrant and shes running good now. So 1. boost leaks 2. n75 and 3. muffler were the issues. Thanks for all the help guys

[SlowDr1v3r]

Oh and diverter valve o-ring was also leaking.