Is this normal? Boost leak test question

[stealthtt24]

First off, Hi! Second, so I did a boost leak test at the throttle body with a homemade tester (since when I did a boost leak test at the FP 3065 turbo, it was leaking air into crankcase), set my compressor regulator to about 20 pounds and had at it. First, i have a leak at the stupid tester, so I will fix that, I have two small leaks at ports at the intake manifold, but nothing major.

But I take the oil cap off and I can still feel/hear air coming out! Not a whole lot but some. I dont hear any oil bubbling as I did before though. No air coming out of my exhaust, and the boost the whole time was at minimum 26 pounds (via boost gauge) and max almost 30. So where do I sit? Obviously fix my 2 small leaks at the intake manny ports and boost leak tester but other than that do you guys think im OK or are my valves leaking?

My PCV valve has been eliminated and is running the two valve cover ports into a vented catch can. Also I have done a compression test and the numbers were fine.

I followed what to do just like oldmans post at the bottom of this page
http://www.dsmtuners.com/forums/articles-turbo-system-intercooler/169435-boost-leak-test-how-boostpro-net-tester.html

 

[joyfil2001]

what exactly is your question? are you actually having driveability problems?

 

[stealthtt24]

No, I just want to make sure I have no boost leaks. My question is, is it ok that i am leaking air into my valve cover when the tester is at my throttle body and if its not ok, what is the cause?

 

[joyfil2001]

yes that is normal. how are you closing off the intercooler piping that goes to the throttlebody?

 

[stealthtt24]

I'm not. Since I have the boost leak tester hooked up at the throttle body elbow, I just have the intercooler pipe hanging there since i'm not testing it at the turbo.

 

[stealthtt24]

Bumping this from a thread I made on other forums:

So I hate boost leaks, and decided since the motor is out of the car, why not try to see if i can find any. 1g 7 bolt motor with good compression, stock cams and intake manifold. Tested it at the TB elbow with an air fitting on boost leak tester, got a little leak on the tester but other than that, nothing except for the one major leak. Tested it to 30 psi and same results. Oh, turbo is a BB FP3065.

Its coming out the valve cover, the two ports. My PCV has been eliminated and if I hold both ports on the valve cover, I can hear a bubbling, not sure if its trying to go thru the turbo or what.

I did a search on several dsm websites and it seems as though (since my compression test were good) that I might have bad valve seals. Should I do a leakdown test to check them? I dont recall seeing a lot (if any) of blue smoke on startup, but its been awhile since then.

 

[95blackGsTurbo]

Do a leakdown test. Doing a boost leak test at the TB is sort of pointless. You need to do one at the turbo inlet to test all of your IC piping, blow off valve and the sealing at the throttle body. Doing it at the throttle body only tests the throttle body gaset, throttle body seals and intake manifold gasket as well as a few vacuum line. If anything is blowing by in the crankcase it's not a boost leak. It's call blowby. If you have good compression numbers then you need to move to a leakdown test to see how much you are leaking. Should be a very low percentage as long as everything is in good shape, 3-4%. If your valve stem seals were bad you would most likely be getting some smoke in the exhaust from the oil leaking into the combustion chamber. Is there any particular reason for all the boost leak testing on just the motor?

 

[stealthtt24]

I hate boost leaks, and just wanna make sure I have none so I can tune. Where can I get ahold of a leakdown tester?

 

[95blackGsTurbo]

Most autoparts store's will rent them out to you instead of buying one. They are pretty expensive to buy.

 

[stealthtt24]

Ive been to Napa, Discount auto parts, Carquest, and Pep boys. No one rents or carries them, this sucks!

 

[stealthtt24]

OK well put the car to TDC and tested it, still leaks out the valve cover! Got a friend who has a leak down tester and im going to get it in the next day or two...

 

[loba]

Wait - you're running a boost leak test at the throttle body? Why?

Listen to stroked he has the right idea. attach it to the TURBO inlet and test. It's very unusual to have an audible leak at 30 psi from the cylinder. That means air is blowing out of the combustion chamber through the rings or (more likely) that one of the intake valve seals is bad. I think while mistakenly testing for boost leak you've discovered a valve leak. Check your oil for gas, that'll solve your problem.

 

[95blackGsTurbo]

OK well put the car to TDC and tested it, still leaks out the valve cover! Got a friend who has a leak down tester and im going to get it in the next day or two...

I have 1500 miles on my 2.3. 205 compression all across the board, brand new valve stem seals, and everything else you could imagine in the head and with my oil cap off while running there is a small amount of air coming out of my oil cap. It's normal. That's why the PCV system and breather assembly comes off the valve cover, to release this pressure.

 

[stealthtt24]

OK thanks guys, I have seen in writeups to do boost leak test at the TB and at the turbo. I have the leak down tester in my possesion and will be doing it here shortly and will report the results.

 

[stealthtt24]

Ok so I redid the test since it wasnt at TDC...

Cylinder #1 leaked 12% out of the oil cap at 98 psi...

Cylinder #4 leaked 17% out of the oil cap at 100 psi...

Im going to do 2 and 3 later, but what does this mean? I know 12% is good, but how about 17%? The motor has about 10k miles on it....

 

[95blackGsTurbo]

http://www.geocities.com/dsmgrrrl/FAQs/leakdown.htm

You still never gave us your compression numbers.

 

[stealthtt24]

Ive read that website and that doesnt help me? Compression test was done a few months ago in the car, heres the post...

Did a compression test, also, I just let the car idle for a few minutes to get warmed up, should I have driven it around the block? All spark plugs taken out and throttle wide open. First was a dry test.
Cyl 1- 150
Cyl 2- 150
Cyl 3- 150
Cyl 4- 145

Then with a cap full of oil poured in the cylinders
Cyl 1- 195
Cyl 2- 195
Cyl 3- 195
Cyl 4- 200

 

[95blackGsTurbo]

Almost time for a rebuild. Numbers are nice and close but getting low.

 

[stealthtt24]

Those were done on a barely warmed up motor, so they would have been higher if I just took the car for a good drive, Im confident they would be in the 165-170 range.

 

[stealthtt24]

Ok so here are results of cylinder 2 and 3...

Cylinder #2 was 11% out the oil cap at 100 psi...

Cylinder #3 was 16% out the oil cap at 100 psi...

so these are ok I imagine?

 

[stealthtt24]

Finally got it right, results done on a cold motor since its out of the car.