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Car won’t hold it’s boost I think

2K views 7 replies 3 participants last post by  Drakethesnake 
#1 ·
I have this weird problem when I really get on the gas pedal. Let’s say when launch from first gear and my turbo is giving me the boost that I need, around 4000 to 5000 rpms my car almost loses complete boost and it sounds like it’s running on full engine. It does this when I’m in each gear. I put a new bypass valve on to see if I stretched the diaphragm, it helped a little but it still happens. What is going on. I don’t know what else to do because no one here in Paducah works on turbo foreign cars...
 
#3 ·
It is a 2013, the one code it ran was the crank shaft position sensor. But I got that replaced four months ago. It had a problem starting and I took it to a Hyundai dealership and they put a thicker cap on the battery and it fixed that. Now it has a way better connection. I think when I bought the car there was a tune on it but the dealership said there was a recall on the ECU and they flashed it. Now the sound of my cat pack exhaust isn’t as loud and consistent. I will just be sitting there idling and it sounds like it goes up and down in the sound. It almost sounds like it wants to stall but it doesn’t
 
#5 ·
the factory bypass valve leaves alot to be desired. how are you measuring boost?

when you get to 4k, do you hear a large whooshing sound?
 
#7 ·
ok, good sign then we have something to work with. the whoosh sound means something is not sealing properly.

start at the throttlebody and work your way to the turbo.. there are a few worm clamps en route and expanding clamps underneath. one at the TB, one at the IC inlet up top. these are both easy to get to. if they are factory worm clamps they will have this annoying plastic nub over the adjustment nut which will need to be pryed off and thrown away. if you are familiar with worm gear clamps you will understand immediately once you look. start by giving them a 1/2 turn or so then move on.

keep on going under the car from the IC outlet, hot pipe, resonator and back to the turbo you'll see a mix of worm clamps and expanding clamps under here. same deal with the pipe clamps. if you go through this and still hear the whoosh, you're going to need to replace the expanding clamps with worm clamps.
 
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