boost leak?

[fatness_42]

Sorry guys because the first half of this post was alreaady posted by me. But I did what everyone said and got no results. Now I think the post is to old to get anymore response out of it. FIRST HALF (I am putting the intake manifold under pressure right now and I hear no bubbling no sounds of leak but it will not hold any pressure it just leaks out the exuast not around the manifold but out the tailpipe?) SECOND HALF (Ok so I tried to set it at 9 ATDC and I could not get it to hold any pressure still leak out the tailpipe. I also tried 30 ATDC and about every other crank setting all with the same results. What does this mean? The head was just rebuilt, new valves, springs guilds the whole works.)

 

[fatness_42]

Can I get any reponse please and thank you. I could use the help.

 

[oVaBoost]

so you got a leak out of your exhaust mani or intake mani???

 

[fatness_42]

what do you mean? the air is just racing out the tailpipe. I can't seemed to get the exhaust valves closed. It's not leaking out the either of the manifold from what i can tell. It won't hold enough air to find out.

 

[fatness_42]

I don't even see how it's possible to get all the exhuast valves closed at once.

 

[oVaBoost]

okay so your exhaust side valves they all dont close?? well i think 2 of the valves on exhaust side would stay a lil open but other than that the rest should be closed i you trying to set timing?? or do you have the head off because if its a rebuild it should be find.

 

[fatness_42]

I was trying to pressurize at the J-pipe with the turbo capped off. I also tryed to just pump it in to the intake manifold with the intercooler line plugged right after the BOV. Is this the wrong approach? I don't understand how to pressurize the system if it is just going to go out the tailpipe. The timing is dead on the car is running now. The head was off because the valves got bent. long story. But now it is all put back together and I am trying to check it for boost leaks. I thought maybe it was just leaking through the turbo itself and out the tailpipe but I tryed at the intake manifold as well with the same results.

 

[fatness_42]

Thank you for your input. I'm looking for anwsers and I'm confused.

 

[oVaBoost]

your welcome im confused too im tired sry i didnt help much

 

[fatness_42]

anyone else. please

 

[mentalTSiAWD]

I was trying to pressurize at the J-pipe with the turbo capped off. I also tryed to just pump it in to the intake manifold with the intercooler line plugged right after the BOV. Is this the wrong approach? I don't understand how to pressurize the system if it is just going to go out the tailpipe. The timing is dead on the car is running now. The head was off because the valves got bent. long story. But now it is all put back together and I am trying to check it for boost leaks. I thought maybe it was just leaking through the turbo itself and out the tailpipe but I tryed at the intake manifold as well with the same results.

Manual Boost Controller? disconnected?
Don't jump to conclusions yet my friend. It might not have anything to do with the valves.
It is better to leak test at TDC.

I always disconnect my MBC and plug the line to it. I also disconnect the tubing going to the PVC and plug it. I connect my tester to the inlet of the turbo and pressurize everything all at once.

EDIT: PCV not pvc

 

[fatness_42]

MBC was disconected because I used the hose running from the comprssor housing at the J-pipe to pumped in the air.

 

[fatness_42]

it wasn't leaking out anywhere that I could tell but out the tailpipe. But it was very hard to know because all the air that I was pumping in was racing out the tailpipe in the matter of a few seconds.

 

[mentalTSiAWD]

MBC was disconected because I used the hose running from the comprssor housing at the J-pipe to pumped in the air.

Check your WGA for proper operation, if that checks out, set the engine to TDC and pull the spark plugs and listen for the air leak at the spark plugs(to help isolate the leak). If you don't really hear anything out the spark plug holes, I would say you have a badly cracked turbo/waste gate flapper housing. If you hear a air out of your spark plug holes, I would recommend checking your valves closer you may still have one bent.

P.S. how are you pressurizing? air compressor I hope

 

[fatness_42]

Yeah air compressor. I thoght that too about the it leaking out the turbo and strait to the tailpipe. But I also tryed to push air into the intake as well with the same result. I mean I can hear the air racing out the head into the exhaust manifold and out the tailpipe. Plus I don't see how the valves could still be bent they are all brand new the whole head is except the lifters rollers and cams. New valves all new guides and springs. All surfaced checked for any cracks the whole nine yards.

 

[fatness_42]

I think tomorrow I am going to try again. I will plug the cap the turbo put air in at the J-pipe and pressurize it that way again. Only this time I will plug the intercooler line right before the intake manifold. This way I can atleast know for sure if it is a bad seal in the turbo and check all the intercooler lines. Also I will know if it it the BOV is leaking.

 

[Burtismaximus]

Just checking to throw it out there if one where to pressure test the system isnt the mbc supposed to leak?

 

[fatness_42]

yeah i unhooked MBC right now I have it off completly. I don't want to over work the turbo anymore than i have to if there is a leak. I was just saying that I used the vaccuum hose that was off the J-pipe at the time to pressurize. With the MBC unhooked.

 

[mentalTSiAWD]

Are you leak testing at 0deg TDC? If not, your valves will be at least paritally open.

 

[fatness_42]

i'm also not sure if there is any leaks I don't notice any kind of smoke ever out the tailpipe and my gas milelage is between 26 and 27. It just don't seem to have the same pull as it did before the head was off. And it seems to be worse with the MBC on. I am wondering if the MBC is shot. But it don't seem the same with BCS on either I mean it spools up like normal right around 3000 but something just don't seem right to me. I am also going to changed the Knock sensor back to the one that was on it. I changed it when I had the head because it was easier to get to with the head off. The one I took off worked it was just that the silcone on the back side of it melted off. But it never through the light on or anything. I thought maybe the new knock sensor was picking more knock than the old one so the computer wasn't advancing the timing like normal. So many thoughts and no answers.

 

[fatness_42]

I tried at TDC but some guys on here said to do it at 9 ATDC and 30 ATDC. All with the same results.

 

[fatness_42]

anyone else?

 

[fatness_42]

I guess I just don't understand how the valves leaking boost can be that concerning. And anyways if they are leaking boost than they for damn sure will be leaking compression.

 

[fatness_42]

Thank you guys. I appeciate the help that you guys provided. I'm still don't understand why I was unable to perform a good boost leak check. But nevermind it did not turn out to be a boost leak. It was most defenitly the knock sensor. I guess that is what I get for buying it at oriellys. I am still unsure if that new knock sensor I got was doing a better job than the original or not. Guess I won't know untill I get a datalogger and or dsmlink. If I go that far in my mods. This whole experance has put a little damper in my hopes with this DSM. Like I said ealier in the post the original never through the light, I only change it because it was a little damaged on the backside. The silicone that covers where the wire is scewed into the senor had melted off. So I changed it while I had the head off because it was easy to get to. But again thank you all that tryed to help.