monkonmonk Posted March 21, 2013 Author Share Posted March 21, 2013 Update: I did some light reading about boost leak testing. Long story short I tried it again at 15psi and it was a bit quicker but still nowhere near 1psi/sec. Anyway, I did hear a hissing sound so I started to feel around and finally noticed that it was coming from my AVO TMIC. The previous owner had a methanol injector threaded into the bottom side of the TMIC and when I received it, I replaced it with a bolt and o-ring. The noticed the o-ring was split and the likely source of the leak. So, I teflon taped the bolt and then proceeded to RTV the entire bolt head. I will need for it to dry, but could this be the issue? How do I know if it is safe to check it, a.k.a. drive the car? Looking to maybe reinstall in the morning and then reset the ECU and try again. Anything else I should be investigating before I do any of this? Thanks. Link to comment Share on other sites More sharing options...
fahr_side Posted March 21, 2013 Share Posted March 21, 2013 You just have to go through these things one by one until you don't leak anymore. Have you burned off your suspect fuel yet? Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
monkonmonk Posted March 21, 2013 Author Share Posted March 21, 2013 Nope, I have about a 1/4 of a tank left. I thought about getting some 93 and adding octane booster just to make sure. I will check for leaks again once the rtv dries. I was also going to clean the MAF sensor tomorrow as well. Link to comment Share on other sites More sharing options...
fahr_side Posted March 21, 2013 Share Posted March 21, 2013 Siphon that shit out and use in your lawnmower / whatever. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
monkonmonk Posted March 21, 2013 Author Share Posted March 21, 2013 I guess I should have been clear. My car has never seen anything other than 93 octane. I meant that I would get known 93 and add the octane booster to confirm it was at least 93. But, still probably not a bad idea to get out as much of the 'bad' stuff as I can. I will reconfirm a boost check this evening after the RTV cures and will also clean the MAF sensor before putting anything back together. Link to comment Share on other sites More sharing options...
fahr_side Posted March 21, 2013 Share Posted March 21, 2013 I got that part. Diagnosis is all about knocking down possibilities one by one. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
monkonmonk Posted March 21, 2013 Author Share Posted March 21, 2013 Ah, gotcha. Just wanted to make sure I was being clear. Siphon this evening also. But, should I be checking it in between all of these things to be able to pin point what exactly was the problem? Or is it too dangerous to do that? Link to comment Share on other sites More sharing options...
fahr_side Posted March 21, 2013 Share Posted March 21, 2013 I'd say put good fuel in and fix your leaks first, then log some and see what happens. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
monkonmonk Posted March 22, 2013 Author Share Posted March 22, 2013 No more leaks found losing about 2-3 psi per second. Replaced the gas and reset the ECU... More to come...LV only as my laptop decided to crap out on me again. Link to comment Share on other sites More sharing options...
iNVAR Posted March 22, 2013 Share Posted March 22, 2013 Uh, 2-3 psi per second is a big loss. Link to comment Share on other sites More sharing options...
monkonmonk Posted March 22, 2013 Author Share Posted March 22, 2013 Whoops my bad. I meant 2-3 seconds per psi. Link to comment Share on other sites More sharing options...
mmmmspecb Posted March 22, 2013 Share Posted March 22, 2013 Good luck! I'm going through a very similar process and it sucks... Link to comment Share on other sites More sharing options...
monkonmonk Posted March 22, 2013 Author Share Posted March 22, 2013 Alright, so I just drove nicely (read: no boost) all day and then right before I came home I switched it to Sport # for one time in the throttle. I saw it go to 12-13psi and stumble heard a leak and stopped. I came home and pulled this LV. I am going to check boost one more time with the leak tester and then I am going to switch back to my stock TMIC and see what that does. Could this be a BOV issue? (running stock currently) Thanks. Link to comment Share on other sites More sharing options...
monkonmonk Posted March 22, 2013 Author Share Posted March 22, 2013 Alright, so I did one more boost test leak and all seems pretty well but there is definitely some air leaking from somewhere under the left side of the intake manifold closer to the center of the engine. Ideas where to look. I guess I don't know what I can remove and still continue to run the check again to inspect for leaks. It only happens at higher psi ranges. At lower psi ranges the loss is negligible. For, example it basically will settle somewhere between 6 and 8 psi and just stay there until I relieve the pressure. Very frustrating... Link to comment Share on other sites More sharing options...
monkonmonk Posted March 23, 2013 Author Share Posted March 23, 2013 So, I took some things apart and noticed that the third hose as you follow the main intake hose back (the largest of the three) was slid back from its mounted location. Am I supposed to pinch this off somehow when pressure testing? I cannot see anything else that could at all be the cause since this is normally under vacuum. Any other ideas as that is the rough area where it sounds that the leak could be. i tried to hold this hose together during another test, but I am not sure how successful I actually was. Link to comment Share on other sites More sharing options...
fahr_side Posted March 23, 2013 Share Posted March 23, 2013 You could just order that Chevy small block water outlet gasket for the turbo to TMIC interface and have peace of mind. Loads of posts on that here. Mr. Gasket... forgot the part number. Do you still the have the soft rubber couplers on each end of the intercooler to throttle body hose? A lot of people have issues with those popping off and just remove then. You just clamp the hose straight onto the IC and TB. If the TB hose seems short, there are aftermarket ones which are longer. Is that a Perrin or AVO TMIC? Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
monkonmonk Posted March 23, 2013 Author Share Posted March 23, 2013 fahr, I already have the Chevy gasket and it looked great the 5 times now the TMIC has been off. As for the rubber couplers, they are gone too as I had issues originally getting everything all hooked up. TMIC, yes, is indeed AVO. I started with a Perrin but had WAY TOO much clutch interference. I reattached the hose that had previously blown off, I think to my original 18psi test. I reset the ECU and went for a drive. I made about 5-6 pulls to redline making peak boost. Obviously not all the way to redline since I still have just a wee little VF46. I made it back home and took this LV. Something tells me either I am not out of the woods yet or I need to do some more miles. Thanks again for all the help. Right now I am thinking that the TMIC leak was the original culprit in the first place. Link to comment Share on other sites More sharing options...
fahr_side Posted March 23, 2013 Share Posted March 23, 2013 Mmm... not enough time for fuel trims or IAM to settle down. Drive some more, normal driving, and check again to see if IAM goes to 1.00 or you have more knock. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
monkonmonk Posted March 23, 2013 Author Share Posted March 23, 2013 Cars and coffee tomorrow so I will check it after that. Thanks. Link to comment Share on other sites More sharing options...
iNVAR Posted March 23, 2013 Share Posted March 23, 2013 You have an AVO TMIC? A few words of advice: 1) The bottom bolt hole for the BPV for some stupid reason actually goes all the way through and is a potential source of a leak. 2) The holes are not reinforced and the bolts are only 10mm which means it is extremely easy to strip if you attempt to overtighten. 3) It wouldn't be a bad idea to put RTV onto the lower 10mm bolt prior to threading it in and then letting it dry for a few hours to ensure the seal is good. Or teflon tape I suppose would work too. Whatever you want to do. 4) You may want to have a helicoil and tapping kit on hand for when that 10mm bolt inevitably strips. If/when that happens, be sure to clean out all the metal shavings that will fall into the endtank. 5) What sort of gasket are you using on the BPV? Link to comment Share on other sites More sharing options...
spec.B Dream Posted March 23, 2013 Share Posted March 23, 2013 Zip tie all vacuum/boost hoses. ALL OF THEM! The one under the intercooler is a pain to re-attach. The one between the intake manifold and the fuel pressure regulator can ruin your engine if it pops off. Link to comment Share on other sites More sharing options...
monkonmonk Posted March 23, 2013 Author Share Posted March 23, 2013 Update....It looks like no knock, but these values can't be good. I did notice what I thought sounded like wastegate flutter near redline. Also, I noticed the boost drop off more significantly than I remember when I first was tuned. Say to like 14psi or so at 6k rpm in 2nd or 3rd. Ideas? Do I still have a leak? BPV? Wastegate? Very frustrated... Link to comment Share on other sites More sharing options...
fahr_side Posted March 23, 2013 Share Posted March 23, 2013 Fuel trims aren't too bad. I like to see negative numbers rather than positive, but anything within +/-5% isn't bad. IAM being so low is more worrying. When IAM is that low you will running low timing and the boost control system may also be disabled, meaning you're on wastegate boost. Of course under these circumstances there should be no knock. Why is the DTC reader disabled? Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
iNVAR Posted March 23, 2013 Share Posted March 23, 2013 Did you pay attention to my last post about where to look for a leak? Link to comment Share on other sites More sharing options...
fahr_side Posted March 23, 2013 Share Posted March 23, 2013 One of these days we're going to have to create a master check list for intake / boost leaks.... Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
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