What is this BLT saying?

[@TDC]

Hey guys. I've been boost leak testing and I basically got all of my leaks fixed but I'm still not holding pressure. I am leaking out of my vacuum line that comes off of my valve cover and goes into my intake pipe. I also am leaking out of my PCV valve. I took it the line off if the PCV that goes to the intake mani and plugged the nipple on the intake mani. I had boost leaking out of the PCV. So basically I have boost leaking into the crankcase. This could either the rings or valve seals correct? I tried closing the intake valves by setting it the motor to 40* BTDC but I couldn't find the part where there all closed. There was always one cylinder that had the intake valves open when I would test. I rotated the crank at least 15-20 times trying to find this point. Is I am only needing a tune to have my car finished performance wise. Is it even worth going through with the tune at this point? Here is a video of my test. You can see and hear the leaks coming from the vac line and PCV valve. Also keep in mind that my gauge on my tester is zeroed at the 9psi mark. This text was done from the throttle body elbow with 20psi. Any help is appreciated.


http://youtu.be/rRaIl2QkK_E

 

[92AWDHX40]

Are there any other leaks.

 

[@TDC]

Are there any other leaks.

No there are not. I sealed every other leak. I put my fingers over the PCV and vac line and it leaks out after about 1.5 mins.

 

[leepen]

I would check the TB seals. With presure in the system wiggle the spring on the TB and use soapy water. That was my problem. Side note I had a friend put presure on the TB spring, the gauge shot up to 40 psi and blew the tested off (big bang) scared the pi$$ out of us

 

[xxNocturnalxx]

Use this check valve inline with your pcv valve.

https://www.rtmracing.com/xcart/product.php?productid=16861

 

[WES_393]

The pressure coming from the crank case is just blow-by. It's normal (to an extent) on a cold engine with open intake valves.

I would also suggest the soapy water method: Keep the intake pressurized while you spray everything down with soapy water and watch for bubbles.

If your concerned with the amount of pressure leaking into the crank case, then run a separate leak-down test of the cylinders. http://www.dsmtuners.com/forums/articles-engine-fuel/338152-compression-leak-down-testing.html

 

[habitatguy187]

The check valve is a godsend.

 

[@TDC]

Thanks for all of the help guys. I used the soapy water method and have every other leak plugged up. I rebuilt the throttle body with new shaft seals and they hold great. I also have new injector seals new throttle body gaskets. Sealed the ISC plate and FIAV plate. So no leaks coming from there either. I deleted emissions. No leaks coming from my Tial Q or speed density map sensor or IAT. Intercooler with all couplers are fine. The only place that leaks causes the boost to leak out are the places in the video above.


My assumption is if I connected the PCV during the BLT then it should be closed when I perform the test correct? This means that the oil dip stick and vac line that goes into the intake should be the only leaks left. But it the car was on and the turbo was spooling to create boost wouldn't the turbo suck all of the excess crank case pressure out of the crank case? Then the dip stick would not leak right? Does this sound right or am I missing something?? It will leak during the BLT when the turbos not spooling because that's the only place left for the crankcase gasses to escape right?

 

[WES_393]

My assumption is if I connected the PCV during the BLT then it should be closed when I perform the test correct?

Correct, it should shut to prevent boost from entering the crankcase, but it's pretty typical for the valve to leak slightly. That's the reason for the check valve suggested.

But it the car was on and the turbo was spooling to create boost wouldn't the turbo suck all of the excess crank case pressure out of the crank case? Then the dip stick would not leak right? Does this sound right or am I missing something?? It will leak during the BLT when the turbos not spooling because that's the only place left for the crankcase gasses to escape right?

Yes, the vacuum created by the turbo seriously helps reduce the pressure. However, there are still limits to how much the stock system can vent. More info can be found here: http://www.dsmtuners.com/forums/articles-engine-fuel/366890-4g63t-pcv-system.html

But I wouldn't worry about air coming from the crank case during a boost leak test. What really matters is that your leak free from the turbo to the intake manifold.

 

[@TDC]

Correct, it should shut to prevent boost from entering the crankcase, but it's pretty typical for the valve to leak slightly. That's the reason for the check valve suggested.



Yes, the vacuum created by the turbo seriously helps reduce the pressure. However, there are still limits to how much the stock system can vent. More info can be found here: http://www.dsmtuners.com/forums/articles-engine-fuel/366890-4g63t-pcv-system.html

But I wouldn't worry about air coming from the crank case during a boost leak test. What really matters is that your leak free from the turbo to the intake manifold.

Great! That makes me feel so much better! I think I may be finally ready to start my tune!