FoxTrotZuluOne Posted January 7, 2016 Share Posted January 7, 2016 Hello, I have a 2005 LGT with 216k miles. Lately it has started to make a hissing noise while making boost on the passenger side. Sounds like air is leaking out... What i have done so far: 1. Replaced intercooler because i thought it was leaking (had oil at the seem). Didnt help. 2. Checked the "Blue T" under the intercooler, its good. 3. Checked Turbo shaft play. Absolutely none. (Original turbo...) 4.Checked hose clamps and air filter box. (just has a drop in panel filter, had it for a long while now) 5. Checked boost on Cobb Accesport. It makes good boost (Should i data log??????????:confused::confused:)(Possible wastegate issue?) 6. Adjusted the spring preload on my GFB BOV. 7. preformed a smoke test and found nothing useful... A little while ago i replaced my spark plugs. also i have been getting really poor MPG (13-15 city) (even before the plugs). Also the car idles kinda low when you come to a stop every now and then. Any ideas and help would be greatly appreciated. Link to comment Share on other sites More sharing options...
sanchitosonria Posted January 7, 2016 Share Posted January 7, 2016 What map are you using on the Cobb AP? Use the AP as a boost gauge. Are you losing pressure? Did you check the tabs on the IC towards the passenger side bottom? Oil at the seam is usually an indicator the tabs expanding from higher levels of boost. Search BPTMIC Link to comment Share on other sites More sharing options...
solidxsnake Posted January 8, 2016 Share Posted January 8, 2016 Sounds to me like you've got a post-turbo leak (running rich --> lower MPG), though you'd see lower boost if that's the case. What is "good boost?" Yes, you absolutely should datalog. Your smoke test might not bring anything up if you only have a leak at boost pressures (13-14psi on the stock tune). I'd check the intercooler as well. Link to comment Share on other sites More sharing options...
whitrzac Posted January 8, 2016 Share Posted January 8, 2016 TB hose "evap solinoid" on the front of the engine near the alternator Pre turbo exhaust leak. Link to comment Share on other sites More sharing options...
FoxTrotZuluOne Posted January 8, 2016 Author Share Posted January 8, 2016 Sounds to me like you've got a post-turbo leak (running rich --> lower MPG), though you'd see lower boost if that's the case. What is "good boost?" Yes, you absolutely should datalog. Your smoke test might not bring anything up if you only have a leak at boost pressures (13-14psi on the stock tune). I'd check the intercooler as well. What map are you using on the Cobb AP? Use the AP as a boost gauge. Are you losing pressure? Did you check the tabs on the IC towards the passenger side bottom? Oil at the seam is usually an indicator the tabs expanding from higher levels of boost. Search BPTMIC For the both of you: I am using the Stage 1 93 oct map. i got 14.16 psi on my way home just now. The intercooler is one day old. its a brand new AVO intercooler. I changed it because the tabs on the old one were oil covered and i though that was the source of my leak. but it wasn't, the noise is still there. I will see about data logging with my AP today. I have never done it, so i will have to do some research. Thanks for the help so far! TB hose "evap solinoid" on the front of the engine near the alternator Pre turbo exhaust leak. The car does have a sti up pipe on it from the previous owner oh so many miles ago..... Do you have a picture of this solenoid you are referring to? I am unfamiliar with it and i would love to inspect it???? Link to comment Share on other sites More sharing options...
bigleben Posted January 8, 2016 Share Posted January 8, 2016 Some reading that might help http://legacygt.com/forums/showthread.php/intake-vacuum-leaks-and-you-pics-inside-235626.html Taken from Tuning alliance thread Leak Test: You will need, a flat head screw driver and a plug for the intake 2.75” OD (aerosol can, spray paint etc will work). You remove your intake from your inlet tube, then insert the can into the coupler just in front of the inlet tube. Next you remove the vacuum source line from the by-pass or blow-off valve and blow into the source line (which connects to the manifold). Try not use above 5 psi because the inlet, pcv, and valve breathers will be under pressure and could pop off or generate a leak. The breathers normally do not see boost pressure. I typically blow into the line with my mouth (lungs) because its quiet and easier to hear air coming out of the system. Once all leaks are contained I blow into it and put my thumb over the hose for 3-4 seconds, then release my finger, and it should still contain some pressure and you can hear it hiss back out at you. A smoke test is another good way to locate leak sources but a smoke machine is needed. Link to comment Share on other sites More sharing options...
Subakook Posted January 9, 2016 Share Posted January 9, 2016 The last time I heard a "hissing" under my hood it was the downpipe to turbo conection. Link to comment Share on other sites More sharing options...
FoxTrotZuluOne Posted January 29, 2016 Author Share Posted January 29, 2016 I think it might be my turbo inlet hose. i was able to peek at it a little and the clamp is digging into the silicone and destroying it (its the stock one). However if it was leaking, wouldn't it cause a lean condition? At WOT i saw 11.03 AFR. So its not lean... Also who i blip the throttle i can here a little whistle when the window is open and the hood is up. Any advice would be helpful. Im currently unemployed and just dropped $700 on an AVO intercooler to try to fix this issue. So i dont want to replace anymore unnecessary parts. Thanks for all the help so far! Also i noticed the my fuel correction isn't pegged at 25. I yanked off a random vac line and watched the value jump up. Link to comment Share on other sites More sharing options...
FoxTrotZuluOne Posted February 2, 2016 Author Share Posted February 2, 2016 https://drive.google.com/file/d/0B6H2ez3qfiXkYjNSRXpVVVk4Smc/view?usp=sharing Here is a video of the sound i am hearing. Its only when you first tap the throttle. I also have that loud sucking noise while making boost. Im thinking the 217,000 mile turbo inlet is ripped. Link to comment Share on other sites More sharing options...
gimpydingo Posted February 2, 2016 Share Posted February 2, 2016 https://drive.google.com/file/d/0B6H2ez3qfiXkYjNSRXpVVVk4Smc/view?usp=sharing Here is a video of the sound i am hearing. Its only when you first tap the throttle. I also have that loud sucking noise while making boost. Im thinking the 217,000 mile turbo inlet is ripped. 217k on the inlet? Wow! I got about 70k or less out of mine before it ripped. Link to comment Share on other sites More sharing options...
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