2G Boost Leak Need Help Fast...System not holding pressure

[AWD96TSI]

Bring everyone up to speed as to whats happening. I have installed a SSAutochrome FMIC w/ short route piping. Also I have the "2g Solution kit" from Turbochargers.com. Before all this went on I just got my head back from the machine shop. The cleaned and installed new valve stem seals. They also had to put in new intake lifters. Now we brought it home and put it back on with a factory headgasket and arp head studs. Basically we are ready to prime the turbo and start the car. Before we did that wanted to make sure there were no boost leaks. This is where I am lost. We pressurize the system to 20 psi. There is not a leak at any of the couplers or gaskets. The boost guage only reads 3-5 psi though . As we are scratching our heads trying to figure out where it is going. I went to through something in the trash can and hear air coming out the exhaust ? Alot of air. I need help fast guys. We also eliminated vaccumm lines via Taboo Speed shop. Sorry for it being so long. If you need to now anything just ask. I have the laptop out in the garage. Thanks

 

[burtreynolds]

The TB is closed, correct?

 

[AWD96TSI]

The TB is closed, correct?

Yeah the plate is closed. I have also opened it too and nothing. But the air is definetly coming out the exhaust. Could the machine shop put the head back together wrong? Or is that even possible?

 

[donmagicjuan]

It's possible that your engine is at a point in its rotation where both the intake and exhaust valves are open for one of the cylinders. If you can, try rotating the engine a bit and see if the leak disappears. Also, since the turbo hasn't been primed yet, I would try applying pressure to a point downstream of the turbo, e.g. the IC pipe, if you aren't doing so already. If it leaks only when testing from upstream of the turbo, you've isolated the problem.

 

[AWD96TSI]

It's possible that your engine is at a point in its rotation where both the intake and exhaust valves are open for one of the cylinders. If you can, try rotating the engine a bit and see if the leak disappears. Also, since the turbo hasn't been primed yet, I would try applying pressure to a point downstream of the turbo, e.g. the IC pipe, if you aren't doing so already. If it leaks only when testing from upstream of the turbo, you've isolated the problem.

Ok, I'll try the tester after the turbo. Now I just capped the egr nipples off. I don't have a block-off plate yet. Should I re-connect that? I was reading something about it could be letting the air escape too? Or am I confused about its operation? Sorry for all the questions.

 

[burtreynolds]

Yeah the plate is closed. I have also opened it too and nothing. But the air is definetly coming out the exhaust. Could the machine shop put the head back together wrong? Or is that even possible?

Well, how would the pressure be reaching the head? Through the intake tract, into the throttle body, through the intake manifold, then into the cylinder head is the only way I know. Where are you pressurizing the system, and with what? How are your vacuum lines hooked up? If you eliminated some, did you cap off the sources?

 

[AWD96TSI]

Well, how would the pressure be reaching the head? Through the intake tract, into the throttle body, through the intake manifold, then into the cylinder head is the only way I know. Where are you pressurizing the system, and with what? How are your vacuum lines hooked up? If you eliminated some, did you cap off the sources?

Yeah, all the sources are capped off. I'm going to rotate the valves incase they are overlapping.

 

[donmagicjuan]

After looking at the EGR system diagram in my Haynes manual, it seems likely that without the 'A' line connected to the throttle body, intake manifold pressure could overcome the spring pressure holding the EGR valve shut and result in a leak to the exhaust system. If reconnecting that line doesn't help, I would look into the other things I mentioned earlier.

Good luck.

 

[AWD96TSI]

Ok, so we re-hooked up the egr lines. Did a test and it really didn't make a difference. I turned the crank over and over trying to get it right. No luck. I'm getting frustrated now. So I was just going to prime the turbo. Pulled plugs so it won't start. So we have been cranking it about 10 rotations let the starter cool. Did it about 6 times not really seeing the guage move but its the stock guage. So we took off the oil feed line from the turbo and cranked it and nothing is coming out. Let starter cool and re-peat. Then curiousity got to me and unscrewed the oil filter see if oil came out. Not a drop it is dry. Now my car sat without oil for about a month and now it just saw oil again. That wouldn't make a difference would it? Thanks for the help...getting closer to calling it a day if I can't make progress

 

[donmagicjuan]

This won't affect your priming issues, but have you double-checked that the timing marks are all lined up properly with #1 at TDC? That's the only thing that comes to mind in addition to what's already been covered regarding your boost leak test woes.

 

[oldman]

When #1 is in TDC, #4 = valve overlap, both the intake and exhaust valves are open, air rushes out of the exhaust. Turn the crank clockwise about 30* to avoid valve overlap.

This is where I am lost. We pressurize the system to 20 psi. There is not a leak at any of the couplers or gaskets. The boost guage only reads 3-5 psi though

What people are refering to when they say "I pressurized the system to 20psi" is the reading on the boost gauge, not the air compressor regulator gauge. You can go ahead and increase the regulator to 30-40 psi, the key is to achieve 20psi on the boost gauge, which will reveal most leaks, and allowed no less than 30 seconds before it bleeds down to 0.

As something to shoot for, I just performed a boost leak test on my new setup last night, testing from my LICP immediately after the turbo and the compressor regulator set to 35psi, I was able to pressurize the intake to 23psi. When I stop pumping, it took about 20seconds to bleed down to 15psi (my BOV starts leaking at 17psi), then about 1 min and 30seconds to 6psi, after that it just kinda sits there indefinitely for about 3 mins. The only leaks I found besides the BOV at 17psi was the four autozone rubber fitting caps on my four TB unused fittings as well as some hissing under the VC, probably some from pcv and my 250miles rings. I removed the fittng caps on the TB and looped them in pairs with a vacuum hose, I'm shooting for 30 psi during my retest tomorrow.

 

[donmagicjuan]

When #1 is in TDC, #4 = valve overlap, both the intake and exhaust valves are open, air rushes out of the exhaust. Turn the crank clockwise about 30* to avoid valve overlap.

Sorry for any confusion; I was asking if his valve timing was properly adjusted. I can see now that it might have sounded like I was suggesting he perform a test with #1 at TDC.

Thanks for clearing that up, Bruce.

 

[oldman]

Sorry for any confusion; I was asking if his valve timing was properly adjusted. I can see now that it might have sounded like I was suggesting he perform a test with #1 at TDC.

Thanks for clearing that up, Bruce.

Don, my post was in no way directed towards you, I was implying that since TDC is where most rebuilt engines are sitting in most cases before priming/start up, it is probably the cause of the OP's problem.

 

[tstkl]

Yeah the plate is closed. I have also opened it too and nothing. But the air is definetly coming out the exhaust. Could the machine shop put the head back together wrong? Or is that even possible?

its ok, this newb is just being newbish. The throttle plate never closes all the way. Think about it, at idle, when the throttle plate is "closed" the engine would be starved of any and all air, and it would die. Thats why at idle, your tps reads 10% (or it should at least). Its open even at idle, just a little.

don't rotate the valves, rotate the crank and the valves will move with it.

edit: looks like you guys got everything I said covered already,...

 

[donmagicjuan]

Don, my post was in no way directed towards you, I was implying that since TDC is where most rebuilt engines are sitting in most cases before priming/start up, it is probably the cause of the OP's problem.

Ah, gotcha. Well, no harm no foul then!

 

[AWD96TSI]

We are done for the night but I have an update. Well I screwed up on doing the timing belt. I had the exhaust cam I guess 180 off. I aligned it off the wrong mark. So after fixing that and double and triple checking it is dead on now. So we hooked everything back up and did about a 5 second start-up. It fired right up, but we didn't get any oil coming from the turbo supply line. The supply line is coming off the oil filter housing. It is installed in the exact same spot that the t-25 line was. Since the line was disconnected from the turbo we did put some oil in the turbo itself. We are going to resume tomorrow about 11:00am. So if theres some advice for the new problem. I am open to suggestions and will keep updating tomorrow. Thanks for everyones help and suggestions. I greatly appreciate it. Also the car sat for about a month with all the oil drained as I was waiting for parts to arrive and getting the head worked on.

 

[oldman]

We are done for the night but I have an update. Well I screwed up on doing the timing belt. I had the exhaust cam I guess 180 off. I aligned it off the wrong mark. So after fixing that and double and triple checking it is dead on now. So we hooked everything back up and did about a 5 second start-up. It fired right up, but we didn't get any oil coming from the turbo supply line. The supply line is coming off the oil filter housing. It is installed in the exact same spot that the t-25 line was. Since the line was disconnected from the turbo we did put some oil in the turbo itself. We are going to resume tomorrow about 11:00am. So if theres some advice for the new problem. I am open to suggestions and will keep updating tomorrow. Thanks for everyones help and suggestions. I greatly appreciate it. Also the car sat for about a month with all the oil drained as I was waiting for parts to arrive and getting the head worked on.

See boost leak test does it all , imagine if you would have started the car without the boost leak test. This is probably too late but you should have disabled fuel and spark and crank the car until the oil idiot light disappears or oil dripping out of the turbo return tube.

 

[AWD96TSI]

Update so far today. We have oil pressure now. We took the timing belt off again and spun the oil pump with a cordless drill. So we buttoned everything up. Primed the new turbo, checked for boost leaks. On small leak on the lower intercooler pipe due to a bad weld. O well can fix that easy. So now to the new problem. Before the turbo had oil in it there was shaft play from what I read its normal since there is no oil. Primed turbo started it let it operate at normal temperature and checked the turbo again. Now the shaft play is non existent. But took it around the block and it will blow smoke under boost . Now there was a restrictor in the old t-25 oil line and there is not one in the ss line. Is my oil pressure to much for the turbo and blowing some buy? Do I need to find a little restrictor somewhere? Someone please help almost done with this project.

 

[AWD96TSI]

Last and final update. Well I was getting so mad that I just started the car to bring it in the garage. When I started it no more smoke out the exhaust. Hmm...so took it for a spin. Boosted it and no smoke what so ever. So I guess it doesn't need a restrictor in the line. But a new problem developed. A drip of oil from the timing belt side . It is a very slow drip. Anyhow though it sure is a night and day difference from the t-25. Except for my horrible boost creep to 20 psi. So I will take it easy till I get that taken care of. Thanks for the help.