Tech Article: Boost Leak Test

RSA Supra · 10-14-2002, 10:48 AM

This will vary a little depending on what intake you have, etc. But its pretty much universal.

Please read the entire thread before commencing testing. I take no responsibility for any mistakes made or damages caused on your part. Potential damage from over 60-80psi to oil pan gaskets, oil seals, etc.

Here is what you'll need:

Soup can, small bolt, hose clamp, tire valve stem. (stop by a tire shop and ask for a used one)

Unhook your intake piping and clamp the soup can into the hose. (you'll do this at different positions depending on your intake, but you get the idea right? plug up the intake so no air can get out)

Take the hose off of the intake manifold, (find it by moving back on the outside from the throttle body) plug it with a bolt or screw and clamp it tight.

Take the valve stem and press it up against the nipple.

Then take a high pressure air hose with a tire inflation attachment and pressurize the system. This is where it helps to have a second person, but it isn't necessary.

Hopefully you have a boost gauge because you'll want to watch it for a couple of reasons. First you'll want to see if it is actually building pressure (if not, you either didn't seal things off correctly, or you have a really bad boost leak) and second to make sure that you aren't putting too much pressure in the system. Be careful not to pressurize the system with more than about 12-14psi (should be more than enough to locate any leaks) at which the pressure will probably cause air to rush out of your oil cap. (this is normal)

If you have a boost leak, you should be able to audibly hear it. If you can't figure out its exact location, you may either want to have someone move their hand around and listen/feel for air escaping, or put soapy water on the intercooler piping and look for bubbles.

Happy boosting!!!

10-14-2002, 12:12 PM

Very helpful, thanks for the post

10-14-2002, 02:55 PM

I hate when either the oil cap pops or the can pops off the intake, jumpy...

good post Ryan, its about time someone did an article on this properly.

one thing though, I wonder if its ok to pressure test the system with the oil cap off, since its gonna pop anyway

RSA Supra · 10-14-2002, 09:05 PM

Quote:

Originally posted by Zerosoul
I hate when either the oil cap pops or the can pops off the intake, jumpy...
good post Ryan, its about time someone did an article on this properly.

one thing though, I wonder if its ok to pressure test the system with the oil cap off, since its gonna pop anyway

Thanks! I took pictures a couple of months ago when I tested mine and just got around to posting.

I'm not sure if you could pressure test the system w/ out the oilcap because air is rushing through the crankcase. I guess you could try it by taking it off and watching the boost gauge. But I doubt it'd work.

Perhaps someone can make this sticky or add it to the FAQ.

10-14-2002, 09:10 PM

is the soup can empty or is it unopened?

NickT916 · 05-21-2005, 04:21 AM

hahaha use a soup to test the soup. Well instead of using one of those huge compressors so you wont blow up your seals, use one of those hand pumps or the electrical car pumps and pump yuor engine up to like 20-30 psi and then listen for the leaks.

im gonna do this tomorrow, ill try and get some picture if i can, sounds like fun.

If ill use the hand pump tomorrow and be pumping my engine , my neighboors will think im on crack or something.

VickSupra · 06-20-2005, 09:49 PM

Quote:

Originally Posted by NickT916

hahaha use a soup to test the soup. Well instead of using one of those huge compressors so you wont blow up your seals, use one of those hand pumps or the electrical car pumps and pump yuor engine up to like 20-30 psi and then listen for the leaks.

im gonna do this tomorrow, ill try and get some picture if i can, sounds like fun.

If ill use the hand pump tomorrow and be pumping my engine , my neighboors will think im on crack or something.

I want to see you pump 20-30 psi by hand...

Actually you only need to go to 8-10 psi. And even that is a fair volume of air.

michaelvanle · 06-20-2005, 09:56 PM

I don't see how the compressor will blow any seals. On the compressor, it has a knob that you adjust what psi you want it to spray out. Just set it to like 25psi (or whatever your high boost is) and listen for leaks.

BTW this is hard as shit. I have a bunch of leaks around the VSV but I can't pinpoint it out. I replaced most of the vacuum lines, but some of them are hard as shit to get to.

jdmuscle · 06-20-2005, 09:58 PM

wow..nice post!! i have a boost leak and it is driving me nuts, cause the car to run too rich at idle.

bahraini_zupra · 09-29-2005, 06:48 PM

THIS IDEA IS AWSOMMMMEEE i tested this and it worked like dream

thanks aloot guys ..

ali

KevinB6876 · 03-11-2006, 10:40 PM

I suspect I have a boost leak, so I just did this test with both a hand pump and a bicycle tire pump.

I could not build any pressure in the intake mani with either pump. not even 1psi. I even tried with a 12V pump. Instead, all I heard was the sound of air hissing from behind the engine and the hissing got worse the more I pumped. However, pressure remained at 0psi on the pump gauge and the boost gauge while the hissing was occurring.

I suspect this means that I have a bad boost leak. The noise is coming from somewhere behind the engine, but I can't find it! I'm starting to think its either under the car or in an area behind the engine that I can't get to. So far I haven't been able to pinpoint it and its PISSING ME OFF *frustrated*. lol.

I just want to say, I think this idea to test for a turbo boost leak by pressurizing the system is an excellent idea. I was initially skeptical of it, but the more I looked at it and thought about it, the more I started to think it sounded like a good idea. And this was proven in application, because it seems to have found a major leak on my car.

Too bad I can't pinpoint it yet.

Toyota doesn't even have a boost leak test procedure in any of their manuals. Sad. My respect goes out to RSA Supra for coming up with this idea. Thank you RSA. Lemme know if you got any more good ideas.

JohnA · 03-12-2006, 03:09 PM

An easier way to do this is to use a bicycle inner tube cut in half.
It's easier to clamp on both ends (being elastic) and already has a tyre valve attached to it.

Hasn't got a boost gauge but you can sure as hell hear any airleaks.

VickSupra · 03-12-2006, 03:31 PM

Quote:

Originally Posted by KevinB6876

...... Instead, all I heard was the sound of air hissing from behind the engine and the hissing got worse the more I pumped. However, pressure remained at 0psi on the pump gauge and the boost gauge while the hissing was occurring.

I suspect this means that I have a bad boost leak. The noise is coming from somewhere behind the engine, but I can't find it! ......

Was the sound near the EGR valve? Mine did that.
But it does sound like a bad leak.
Is someone helping you? I found I needed help (more ears) in locating the leak.

KevinB6876 · 03-13-2006, 01:22 AM

Quote:

Originally Posted by VickSupra

Was the sound near the EGR valve? Mine did that.
But it does sound like a bad leak.
Is someone helping you? I found I needed help (more ears) in locating the leak.

I've got a friend coming over tomorrow to help me.

KevinB6876 · 03-13-2006, 01:24 AM

Quote:

Originally Posted by JohnA

An easier way to do this is to use a bicycle inner tube cut in half.
It's easier to clamp on both ends (being elastic) and already has a tyre valve attached to it.

Hasn't got a boost gauge but you can sure as hell hear any airleaks.

I didn't exactly understand. What do I do with the inner tube? Please explain in more detail, I'd like to know.

JohnA · 03-13-2006, 02:57 AM

Here is a picture posted from another enthusiast in the UK Supra forum

03-13-2006, 03:11 AM

yeah but that only checks intercooler pipes. how would you check the turbo piping or the intake manfiold ?

KevinB6876 · 03-14-2006, 01:03 AM

Ok fellas, here's an update.

A friend and I did the test again together and once again we got 0psi on the gauge and we heard the hissing noise. The friend noticed the hissing noise was coming from the EGR vacuum modulator (the valve with the green top that sits right on the top of the intake manifold next to the EGR valve). I also listened and verified it, the hissing noise was coming from inside the EGR vacuum modulator. Is this modulator supposed to be making a hissing noise when the system is pressurized? Is this normal? Vicksupra said he had a noise coming from near the EGR also, but he didn't elaborate. Is the EGR vacuum modulator leaking the pressure or is this noise normal?

After realizing that the noise was coming from the EGR vacuum modulator and suspecting the modulator might be bad and leaking the pressure, we disconnected the hose to the EGR vacuum modulator, bypassing the modulator, and did the pressure test again hoping that we could build pressure this time. Once again, 0psi was showing on the gauge, except this time we heard a hissing sound from the intake where the soup can was clamped. Suspecting that the soup can was leaking the pressure, we reinstalled the soup can into the intake to get a more firm fit and tightened the clamp on it even tighter than before. We then did the pressure test again using a 12V air compressor, and the soup can popped off the intake! lol.

At this point, we realized that the soup can wasn't holding properly into the stock plastic intake hose and was leaking pressure, so im ordering a boost leak tester from http://www.speedforsale.com/newparts...d35257368c53c4

and we're gonna try the test again. Hopefully this time the boost leak tester will hold the pressure dammit.

KevinB6876 · 03-14-2006, 05:20 PM

So guys, is the EGR vacuum modulator supposed to be making a hissing noise when the system is pressurized?

house_of_senate · 03-14-2006, 08:39 PM

mine also makes the sound from the egr.

KevinB6876 · 03-15-2006, 12:48 AM

Quote:

Originally Posted by house_of_senate

mine also makes the sound from the egr.

So is this considered normal? Or does this mean that our EGR vacuum modulators are leaking?

If normal, shouldn't we disconnect the EGR vacuum modulator so that its hissing doesn't make it harder to hear other potential leaking noises?

house_of_senate · 03-15-2006, 06:12 PM

i would also like to know if its normal or not...

house_of_senate · 03-15-2006, 10:25 PM

yes it is normal.

KevinB6876 · 03-17-2006, 07:13 PM

Quote:

Originally Posted by house_of_senate

yes it is normal.

Wait. How can you say its normal if you don't know if its normal and would also like to know if its normal or not?

JohnA · 03-18-2006, 02:50 AM

this guy's mother thinks he's normal, but others beg to differ

(i.e. Define 'normal')

10-14-2002, 10:48 AM	#1
RSA Supra Administrator Auto Admin Join Date: Feb 2001 Location: 3.4 cars in front of your 6 speed (So Cal) Age: 31 Posts: 6,824	Tech Article: Boost Leak Test This will vary a little depending on what intake you have, etc. But its pretty much universal. Please read the entire thread before commencing testing. I take no responsibility for any mistakes made or damages caused on your part. Potential damage from over 60-80psi to oil pan gaskets, oil seals, etc. Here is what you'll need: Soup can, small bolt, hose clamp, tire valve stem. (stop by a tire shop and ask for a used one) Unhook your intake piping and clamp the soup can into the hose. (you'll do this at different positions depending on your intake, but you get the idea right? plug up the intake so no air can get out) Take the hose off of the intake manifold, (find it by moving back on the outside from the throttle body) plug it with a bolt or screw and clamp it tight. Take the valve stem and press it up against the nipple. Then take a high pressure air hose with a tire inflation attachment and pressurize the system. This is where it helps to have a second person, but it isn't necessary. Hopefully you have a boost gauge because you'll want to watch it for a couple of reasons. First you'll want to see if it is actually building pressure (if not, you either didn't seal things off correctly, or you have a really bad boost leak) and second to make sure that you aren't putting too much pressure in the system. Be careful not to pressurize the system with more than about 12-14psi (should be more than enough to locate any leaks) at which the pressure will probably cause air to rush out of your oil cap. (this is normal) If you have a boost leak, you should be able to audibly hear it. If you can't figure out its exact location, you may either want to have someone move their hand around and listen/feel for air escaping, or put soapy water on the intercooler piping and look for bubbles. Happy boosting!!! __________________ -Ryan Hawkins 1993.5 Supra PHR Stage 1+, 3.4L Stroker, BL Auto My Website My Mods My Pictures

06-20-2005, 09:58 PM	#9
jdmuscle SUPRAS FOR LIFE Join Date: Jul 2004 Location: 10 cars ahead of u!!!! Posts: 2,278	wow..nice post!! i have a boost leak and it is driving me nuts, cause the car to run too rich at idle. __________________ 94 BALTIC BLUE......720RWHP 06 Z06...................541RWHP 04 LS430................241RWHP

09-29-2005, 06:48 PM	#10
bahraini_zupra JZ Enthusiast Join Date: Jun 2002 Location: Bahrain Age: 25 Posts: 3,018	THIS IDEA IS AWSOMMMMEEE i tested this and it worked like dream thanks aloot guys .. ali __________________ http://www.cardomain.com/id/ghoshee

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10-14-2002, 12:12 PM	#2
WeaponX Guest Posts: n/a	Very helpful, thanks for the post

10-14-2002, 02:55 PM	#3
Zerosoul Guest Posts: n/a	I hate when either the oil cap pops or the can pops off the intake, jumpy... good post Ryan, its about time someone did an article on this properly. one thing though, I wonder if its ok to pressure test the system with the oil cap off, since its gonna pop anyway

10-14-2002, 09:10 PM	#5
BrianJ Guest Posts: n/a	is the soup can empty or is it unopened?

05-21-2005, 04:21 AM	#6
NickT916 SupraForums Member Join Date: May 2005 Location: Sacramento, CA Age: 29 Posts: 1,102	hahaha use a soup to test the soup. Well instead of using one of those huge compressors so you wont blow up your seals, use one of those hand pumps or the electrical car pumps and pump yuor engine up to like 20-30 psi and then listen for the leaks. im gonna do this tomorrow, ill try and get some picture if i can, sounds like fun. If ill use the hand pump tomorrow and be pumping my engine , my neighboors will think im on crack or something.

06-20-2005, 09:56 PM	#8
michaelvanle Newbie Join Date: May 2003 Location: South Jersey Posts: 11,171	I don't see how the compressor will blow any seals. On the compressor, it has a knob that you adjust what psi you want it to spray out. Just set it to like 25psi (or whatever your high boost is) and listen for leaks. BTW this is hard as shit. I have a bunch of leaks around the VSV but I can't pinpoint it out. I replaced most of the vacuum lines, but some of them are hard as shit to get to.

03-11-2006, 10:40 PM	#11
KevinB6876 SupraForums Member Join Date: Apr 2005 Location: San Diego, CA Age: 33 Posts: 1,560	I suspect I have a boost leak, so I just did this test with both a hand pump and a bicycle tire pump. I could not build any pressure in the intake mani with either pump. not even 1psi. I even tried with a 12V pump. Instead, all I heard was the sound of air hissing from behind the engine and the hissing got worse the more I pumped. However, pressure remained at 0psi on the pump gauge and the boost gauge while the hissing was occurring. I suspect this means that I have a bad boost leak. The noise is coming from somewhere behind the engine, but I can't find it! I'm starting to think its either under the car or in an area behind the engine that I can't get to. So far I haven't been able to pinpoint it and its PISSING ME OFF frustrated. lol. I just want to say, I think this idea to test for a turbo boost leak by pressurizing the system is an excellent idea. I was initially skeptical of it, but the more I looked at it and thought about it, the more I started to think it sounded like a good idea. And this was proven in application, because it seems to have found a major leak on my car. Too bad I can't pinpoint it yet. Toyota doesn't even have a boost leak test procedure in any of their manuals. Sad. My respect goes out to RSA Supra for coming up with this idea. Thank you RSA. Lemme know if you got any more good ideas.

03-12-2006, 03:09 PM	#12
JohnA Misty and Wet Join Date: May 2002 Location: UK Posts: 358	An easier way to do this is to use a bicycle inner tube cut in half. It's easier to clamp on both ends (being elastic) and already has a tyre valve attached to it. Hasn't got a boost gauge but you can sure as hell hear any airleaks.

03-13-2006, 02:57 AM	#16
JohnA Misty and Wet Join Date: May 2002 Location: UK Posts: 358	Here is a picture posted from another enthusiast in the UK Supra forum

03-13-2006, 03:11 AM	#17
Boostinhard Guest Posts: n/a	yeah but that only checks intercooler pipes. how would you check the turbo piping or the intake manfiold ?

03-14-2006, 01:03 AM	#18
KevinB6876 SupraForums Member Join Date: Apr 2005 Location: San Diego, CA Age: 33 Posts: 1,560	Ok fellas, here's an update. A friend and I did the test again together and once again we got 0psi on the gauge and we heard the hissing noise. The friend noticed the hissing noise was coming from the EGR vacuum modulator (the valve with the green top that sits right on the top of the intake manifold next to the EGR valve). I also listened and verified it, the hissing noise was coming from inside the EGR vacuum modulator. Is this modulator supposed to be making a hissing noise when the system is pressurized? Is this normal? Vicksupra said he had a noise coming from near the EGR also, but he didn't elaborate. Is the EGR vacuum modulator leaking the pressure or is this noise normal? After realizing that the noise was coming from the EGR vacuum modulator and suspecting the modulator might be bad and leaking the pressure, we disconnected the hose to the EGR vacuum modulator, bypassing the modulator, and did the pressure test again hoping that we could build pressure this time. Once again, 0psi was showing on the gauge, except this time we heard a hissing sound from the intake where the soup can was clamped. Suspecting that the soup can was leaking the pressure, we reinstalled the soup can into the intake to get a more firm fit and tightened the clamp on it even tighter than before. We then did the pressure test again using a 12V air compressor, and the soup can popped off the intake! lol. At this point, we realized that the soup can wasn't holding properly into the stock plastic intake hose and was leaking pressure, so im ordering a boost leak tester from http://www.speedforsale.com/newparts...d35257368c53c4 and we're gonna try the test again. Hopefully this time the boost leak tester will hold the pressure dammit.

03-14-2006, 05:20 PM	#19
KevinB6876 SupraForums Member Join Date: Apr 2005 Location: San Diego, CA Age: 33 Posts: 1,560	So guys, is the EGR vacuum modulator supposed to be making a hissing noise when the system is pressurized?

03-14-2006, 08:39 PM	#20
house_of_senate SupraForums Member Join Date: Jul 2004 Location: USA Age: 25 Posts: 453	mine also makes the sound from the egr.

03-15-2006, 06:12 PM	#22
house_of_senate SupraForums Member Join Date: Jul 2004 Location: USA Age: 25 Posts: 453	i would also like to know if its normal or not...

03-15-2006, 10:25 PM	#23
house_of_senate SupraForums Member Join Date: Jul 2004 Location: USA Age: 25 Posts: 453	yes it is normal.

03-18-2006, 02:50 AM	#25
JohnA Misty and Wet Join Date: May 2002 Location: UK Posts: 358	this guy's mother thinks he's normal, but others beg to differ (i.e. Define 'normal')