Boost leak

[4everboosted]

I have a 98 gsx that won't boost. It's like it hits rev. Limiter it just won't go anymore right as it should hit boost then if I back off it's normal again, but when I shift I can hear the bov. Big evo3 turbo, 850cc injectors, walbro 255. I did a boost leak test and all I can hear is oil in the crankcase bubbling and a ton of air leaking somewhere in the area of the throttle body/ intake manifold. However I cannot feel any air leaking anywhere. Is that normal to hear that there? Also my turbo does have some shaft play up and down and side to side so I'm going to order a new one before I drive the car anymore but I can't see that being the problem.

 

[92AWDHX40]

Fix the boost leaks use soapy water any leaks are not good.

 

[93tsi6bolt]

Check your tb shaft seals the tend to leak and can be hard to see with soapy water. You will hear it with the boost leak test right at the tb.

 

[4everboosted]

I know any leaks aren't good but I'm saying should the system actually hold pressure? Because I would think it would leak past the intake valves and is it normal to hear the oil bubble? And is it normal to hear it leaking in the throttle body area? Idk what that would even be. Also what does tb stand for?

 

[4everboosted]

Ah I see you mean throttle body by tb. Is it normal to hear any air leak during a boost leak test I guess is my question. And should the system stay pressurized and hold air. I put in 10 lbs and it leaks right off.

 

[synthetek]

It should be able to hold more than 10lbs. Sounds like you have leaks somewhere. The TB can leak from the shaft seals and the biss screw.

 

[lasershark]

When i was researching doing my first boost leak test (BLT); one of the steps was to bring cylinder 1 to top dead center (TDC) up to 6 degrees past TDC. Did you do that?

 

[luv2rallye]

When i was researching doing my first boost leak test (BLT); one of the steps was to bring cylinder 1 to top dead center (TDC) up to 6 degrees past TDC. Did you do that?

Both exhaust and intake are then open on 2 cylinders at TDC to TDC+6.
See here for better position: http://www.dsmtuners.com/threads/bo...th-boostpro-net-tester.169435/#post-152554139

 

[lasershark]

huh? Thats why your the Wiseman I found the post I got my originally got my info from, thanks Google.
http://www.dsmtuners.com/threads/boost-leak-test-gone-bad.372918/
Guess he probably shouldn't listen to that?

 

[luv2rallye]

Ya that post is wrong. There is overlap where both intake and exhaust valves are slightly open on 2 cylinders at TDC (http://www.dsmtuners.com/attachments/intake-exhaust-valve-timing-turbo-jpg.128779/). There is no position where all valves on all cylinders are closed. However there is a position where all intake valves are closed (and another where all exhaust valves are closed).