i do it warm usually, but Ive done it cold before.. but doing it warm is better, because stuff seals way better and gives you a more accurate test in my opinion.

 

Wonder why my car wont hold over 20 psi with a cold engine? perhaps i should do a compression or leak down test.

 

I had an audible boost leak so I decided a boost leak test was in order...I can't build any pressure at all...first time I've ever tried to do a test

here is my set up

hallman mbc
stm valve cover catch can set up w/ breather

I am testing it right off the turbo compressor housing...I disconnected the hallman mbc and plugged the vac lines...do I need to do anything to my catch can set up being that it has a breather?

I just can't figure out where the air is going...I literally can't even hold 1 psi

it's pissing me off

 

no because for it to pressurize the valve cover it has to get past the rings and seals etc.. (unless read below at **) so unless you have a horrible sealing issue theres no reason for a catch can to not allow the system to build boost pressure.

if you have the vac line directly connected to your boost source to your wastegate actuator once you put that certain amount of psi in the system it will crack open the flapper and pressure will also escape the exhaust system.

disconnect the vac line from the wastegate actuator and plug it. even then tho before thats done it should still build wastegate pressure in the system, so if you cant build anything at all check under the intake manifold area.. is your egr blocked off and stuff? check in that area. also quite possibly the crank needs rotated slightly.


** unless you have lines running directly from the intake manifold to the vented can then thats a boost and vacuum leak.

 

I am no expert on boost leak tests however I can tell you that if you cannot even hold 1 psi then you have some serious investigative work to do. It could really be coming out from any of the couplers or even the throttle body shaft seals.

If you are really struggling I recommend a partner to help you out that way someone can operate the compressor while the other person is searching. Taking off the front bumper might also help.

Your catch can setup should not change anything. Technically speaking some air will escape however nothing that significant so it has to be coming from a different source. You would be surprised what you may find. Sometimes the clamps are simply too loose on a coupler, however other times you may find torn couplers, torn vacuum tubing, wrong size tubing, leaky injector o rings, even a cracked intercooler...

Its always an adventure and sometimes what you find may not come as the best news however its better to take care of it instead of leaving power and efficiency on the table not to mention the damage that its causing to the turbo.

 

how can you manually turn the crank?

I will check behind the intake manifold as well...I recently had the egr hose come off and I did put it back on...the car does not sound the same as when that hose came off but I will check

also when you say disconnect the vac line to the wastegate actuator...why would that matter if I disconnected the boost source (mbc)

I'm just trying to make sure I am understanding everything correctly

 

Take a picture of how you have it setup.

You need to make sure you are connected properly and that you're actually getting air to your system. If you're using a decent sized compressor you'd hear a Really loud leak. my guess is that it is just a simple connection issue. You should be able to build at least 5 psi...0psi means your car should be driving like crap and slow as ever. Which I doubt.

 

turns out my egr hose was off again...I zip-tied it on this time around...too late to run the compressor so I put the intake back on and took her out...noise is gone and she is running strong

thanks for the tips tscompusa

 

does anyone have an answer as too if the egr vac line was off could it vent pressure as fast as I injected it?

I followed all the steps in this thread...only things I did not do were run the car first and turn the crank (not sure how)

but I disconnected my mbc and plugged the lines as noted

 

The first couple of minutes of this video show an easy way to find tdc:
http://www.streetfire.net/video/how-...o-8_138721.htm

It all depends on how many SCFM (Standard Cubic Feet per Minute) of air you are injecting. Consider that many home style compressors only put out approximately 2 to 3 SCFM of air. I'm not sure of the diameter of the EGR vacuum port, but it is probably large enough to pass 2 to 3 SCFM of air.

Dan (drb)

 

Anyone making boost leak testers for people who dont have access to regular hardware stores? I'm in South Korea and need one.

 

EGR vac line is off.

 

because when you put more pressure in the system then the actuator is able to handle it will actuate the rod and open the flapper since its connected directly to the boost source.

if you go out and drive your car with the wga directly connected to the boost source you will get your true wga boost curve when you boost the car for your particular setup.

at the same time if you plug the boost source line and disconnect the wga vac line, you will run as much boost as the car can possibly take until the exhaust gases/pressure overpower the spring pressure and blow the flapper open.

Glad you got it sorted out. you could also try alittle dab of gorilla glue to give even more protection on the lines. not to small not to big of a zip tie with the right tension will dig into the vac line and it should never come off again if done right. i have noticed though if i dont use alittle bit of gorilla glue i still get bubbles with soap and water on T'ed off vac lines. but that doesnt occur until around 35psi on the test, and half the time my tester explodes off the compressor housing of the turbo before i even get that high in pressure.

 

@ chaiotix : I normally don't have to turn the crank before doing a test. I believe I have read one or two people having issues building boost and I believe it may have been the egr(I deleted)

 

thanks to everyone that answered...I learned a lot

it was indeed the egr valve hose that was off...I ziptied it and the car is running great

I will be deleting all the egr and evap stuff as soon as I get my tactrix and can handle the ecu end of things

getting a ziptie on that hose without remove the strut bar was fun...one handed and couldn't see but I did it haha