Put the OE tune back in and it barely ran. Swapped the OE map sensor back in and we were back in business. Minor details... took it for a spin and still the same issue. So not a boost leak, not the Bov/DV, not the wastegate, not the tune, not the turbo, doesnt seem to be fuel related.... what's next? Spark plugs getting blown out? They are probably original.

 

Plugs - Ngk ILFR7H. Gapped at .020". Do these come stock?

 

You haven't checked the plugs yet?

 

Beat you to it by 1 min haha. Going to see if the wonderful Autozone has anything good in stock. Will post up results but not expecting anything promising.

 

Before that, you could try pulling them to take a look and check the gap. It's free. 😁
then again ,if they are old ,copper plugs then may as well.

 

Not spark plugs....

 

Here is my quick recap of parts replaced and tests run.

- BOV/DV
- Wastegate
- Spark plugs
- Air filter
- Boost leak test up to 30 psi (throttle body shaft seals leak)
- Checked turbo for shaft play
- Bypassed ECU for boost / now on manual boost controller
- Flashed back in OEM tune / installed factory MAP sensor
- AFR does not go lean when boost cuts
- Voltage does not drop

The car runs absolutely perfect until that magical 5500 rpm. Then the brick wall of no boost. I am just about out of ideas. Actually I am out of ideas....

 

After finding multiple threads of people having the same issue, most with no final conclusion to what the fix was, I have 2 last things to test. Someone said something earlier about the intake snorkel not being bolted down. I see why now. Some say it can suck itself to the hood. I also read that my intake tube can be collapsing. Both makes sense. The same day this all started, I changed the air filter with a cheapo STP (as well as changing a bunch of other things). Of course, I threw out the one that was originally in the car. So step 1, pop the snorkel off and test. If that doesnt help, I am buying a new intake, something aftermarket with a cone filter.

 

Which turbo? I've run the stock inlet with an exposed element filter on an HTA71, but it never collapsed. I've always kept the snorkel, also. If you are running an aftermarket turbo and stock airbox, maybe it's possible the turbo needs to draw more air than the box can allow? That would have to be a really bad air filter, though....

 

I am still on the stock 9 turbo. Keep in mind, my car is 99% bone stock. Just has a cat back. It very well could be the air filter being too restrictive. I cheaped out on it big time.

On a side note, it looks like ETS is having a 20% off sale. You know what that means? Intake and lower pipe have been ordered!

 

I'm 99'9% sure that's not your problem, though.

 

Well they were on sale and I was going to get them eventually anyways....

But if you have any more ideas, I am all ears. I would really like this issue solved.

 

Honestly, I'm stumped. Without having the car in front of me and assuming you have checked all the basic stuff before delving into complicated issues, I just can't think of anything.
It sounds tune related....but it does it with all the stock parts attached. You have changed everything but the turbo and you said it's not that. I dunno, man.

 

You and me both are stumped. I'm desperate at this time. That's why I am willing to try anything haha. I put the stock DV back on and took the intake snorkel off. We will see if it makes a difference. Find out tomorrow. My expectations are not high. After looking at it, I dont see how the snorkel can "suck" to the hood. But it worked for someone else so I might as well try.

 

I have a feeling he had another issue that happened to be resolved at the same time. The snorkel is reinforced and fastened down. But I guess it's remotely possible.
you could always sell the car and start over. LOL