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2G Strange boost issues

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jesse12345

Proven Member
455
329
Jul 30, 2014
Down the block, Minnesota
This may be a very long post so bear with me. I have been doing process of eliminations and I'm getting closer, but I don't want to just throw parts at the car. I have been having a very strange boost issue and everything I do doesn't make it any better. I started with a 14b turbo with a swapped 16g exhaust housing. I did a boost leak test and it sounded like It was leaking from the exhaust housing. So I swapped one of the four t25 I have laying around. Tested for leaks again and I had zero. Now that everything is in good shape, I take the car out and no matter what I do at about 5k rpm it cuts out and I'm really rich. I'll either build boost to 5 pounds or 20 pounds, pretty much whenever it feels like it. I'm at a loss I don't know if timing is being pulled or what is going on, it just hits boost and then starts to bog then falls on its face. If I give it half throttle it'll go past 5k rpm as long as I'm not fully in boost. No matter what I do it'll fall on its face and run pig rich if I give it any more. The car is fully stock aside from fmic and blow off valve. It idles perfect and revs up perfect with zero smoke, but my tail pipe is black so I know it's rich up top. I've been pulling hair out trying to figure this out and I've searched for days now. I could have 2 issues but I feel like they are linked together. Thank you ahead of time if you've made it this far. I've tried everything, I'm just running wastegate boost also. I also can not scan the car since it's a Frankenstein.
 
I'm using nothing to tune with the car is running all stock. I thought it was fuel cut but it more or less gives a quit cut and then it's fine. I don't go flying through the windshield like everyone explains it. I don't even have to be in boost and it'll do it. Feels gutless unless I find the sweet spot then it's fine. I found more boost leaks last night but no matter what nothing is making it better. Feels exactly the same.
 
I have no more boost leaks and brand new plugs and wires. I just checked the plugs again last night to make sure they were gapped correctly. I'm at a loss I've been swapping parts with spares I have laying around, and nothing changes. My idle is perfect, it revs perfect, and drives perfect. Under some heavier throttle I lose power and I get a nice buck with it.
 
How high are you boost leak testing and how quickly does it bleed off? How are your vacuum lines routed? If you're seeing 20psi on a t25 on wastegate you have some serious issues or somethings plumbed wrong.
 
Testing up to 15 psi and it takes about a minute or more for it to bleed off. I ditched the boost controller all together yesterday to eliminate that. So it makes about 10 psi now on wastegate but it's weird because sometimes it'll only make 5 pounds. My boost gauge is tied in with the stock fpr and my bov boost only port is tied in with my wastegate. All of the intake ports are blocked off.
 
That's a current picture? What's going on with your wastegate line routing? I see a T by the turbo that I assume goes to the gate and what else? A blue line coming up to the BOV? A red line going where? Dedicated the gate to it's own boost source, just a loop, no Tee's anywhere. Dedicate the BOV, the rest looks fine from what I see.
 
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