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Headlight Restorer
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Discussion Starter · #1 · (Edited)
Hi guys, the car was fine until yesterday and as soon as i started driving my car, i knew there was something wrong. I couldn't boost past 0.2bar.
The turbo sounds louder(spooling sound on low rpms), and the BOV(HKS) vents louder at low rpms where it shouldn't(2k-3k) Also if i get on it past 3k rpm and let off the gas, the turbo makes a low hum whistle noise after the BOV vent sound.

My car is a 94 TT auto with 59k miles and is in TTC mode with check valves. I heard once that if check valves go wrong or something, this can happen from someone.

can anyone please help me out on what it could be?
thank you for your help!
John


EDIT: problem FIXED! thanks guys
 

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Boost4fun
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1,848 Posts
I would say you have a boost leak at a smaller hose..
Check all hoses and/or perform a pressure check.
Gerd
 

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TE44 NA-T
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1,026 Posts
I would check the intercooler pipes. And the Vacuum lines that go to the bov, and boost gauge.
 

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nureulsaranghae said:
Hi guys, the car was fine until yesterday and as soon as i started driving my car, i knew there was something wrong. I couldn't boost past 0.2bar.
The turbo sounds louder(spooling sound on low rpms), and the BOV(HKS) vents louder at low rpms where it shouldn't(2k-3k) Also if i get on it past 3k rpm and let off the gas, the turbo makes a low hum whistle noise after the BOV vent sound.

My car is a 94 TT auto with 59k miles and is in TTC mode with check valves. I heard once that if check valves go wrong or something, this can happen from someone.

can anyone please help me out on what it could be?
thank you for your help!
John
Why not go into seq. mode and see if things start working (haha)!
 

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Headlight Restorer
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1,107 Posts
Discussion Starter · #6 ·
PROBLEM FIXED! Thanks for all of your help.
the problem was the check valve. it was popped off from the hose. I slapped it back on with a zip tie.
I guess I will go perminant TTC soon.

John
 

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Glad you found your problem- mods come at a price. Speaking of modifying, are you so sure you want to stay TTC seeing is you have a 4AT?
 

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Headlight Restorer
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1,107 Posts
Discussion Starter · #8 ·
MtFujiSupra said:
Glad you found your problem- mods come at a price. Speaking of modifying, are you so sure you want to stay TTC seeing is you have a 4AT?
I just got this car not long ago from selling my 6spd due to my back problem. So I do not know much about TTC and auto tranny. what are the pros and cons for having an auto with TTC?
thanks
John
 

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Bear in mind, my attitude for TTC is merely that of a diagnostic tool and not a trick. Performance, from a standstill, is probably worse than a NA. Exhaust noise is a nuisance if you live in a ritzy neighborhood. The talk is that TTC will relieve the second turbo of any rapid accel. start-up upon transition. All this aside, a properly functioning sequential system is the most tractable. You have tried it so you probably can relate to some of what I say here- you be the overall judge.
 
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