Confused about Boost Leak Test

[sccrAdidas15]

So I followed the boost leak check, built my own tester and hooked it up to the end of the intake which is a freaking PITA!!! I had to take the whole thing off then attach it back to the MAF Sensor then figured how is this going to be pressurized when all the air is just gonna go right through the air filter and MAS sensor and out the other hole?? I"m really confused about this test can someone help me with it??

 

[PieEyedPiper]

heh, you poor sap! j/k!

You take your intake off completely and leave it off during the test. You pressurize your turbo inlet completely bypassing your MAF/intake pipe.

My results aren't so good doing it like that though since my turbo only seals up when the engine is running and oil pressure is high.

My suggestion to you is to test at the turbo inlet, and if you're getting a solid 10psi you're probably doing alright.

THEN, pressurize the intercooler inlet (sooo much easier if you still have the stock licp) and your mission is now to obtain a pressure of ~20psi and have it hold at least 30seconds before it bleeds down to zero. (use your boost gauge to determine the results).

Any other questions? just ask.

 

[sccrAdidas15]

wait im confused so you don't attach it to the intake pipe itself??

 

[sccrAdidas15]

so you actually just stick it on the turbo itself??

 

[grnchevyz]

Go Paint GO!

Hope this helps out.

 

[sccrAdidas15]

iight dude thanx alot!! Yea i was just thinking u hook it up to the intake and i was like wait, that won't work.

 

[grnchevyz]

Glad to help out!

Just follow the diag with PieEyedPiper's instructions and you'll be good to go.

 

[kenamond]

The whole idea of a boost leak test is to make sure that the pressurized parts of your intake tract aren't leaking anywhere.

Since the turbo compressor is the thing that actually pressurizes your intake tract, only parts downwind of the compressor are what you need to test for boost leaks.

You need to remove the filter/MAF/intake pipe assembly so that it's not in the way. I'm a 2g guy, so I don't know what you have to do for a 1g. Just figure it out. You'll definitely have to disconnect the intake pipe from the compressor inlet.

At that point, you can clamp the boost leak tester to where the intake pipe was connected (compressor inlet). Then you apply compressed air to the valve on the tester, but make sure you limit the pressure so that it doesn't go above, say, 20psi, especially if you are using an air compressor.

All of the pipe couplers may leak. The pipes themselves may have cuts or holes in them. The intercooler could have corrosion holes or holes from rocks, and there are numerous gaskets/seals in the throttle body, intake manifold, and injectors that could also leak.

So you want to apply pressure to this whole system and see what happens. A spray bottle filled with extra soapy water (I use Dawn dish soap and water) is great for finding leaks. Just spray it all over each part, coupler, the throttle body, BISS, injector insulators, etc.

So try to get to the point where you can pressurize your intake, then go from there.

 

[sccrAdidas15]

ok well, i just got the intake pipe and the MAS out of the way and hooked the tester to my turbo inlet, i just wanted to check if everything was in working order so i used a bicycle pump and pumped say 10 times and my mom said my gauge only moved to 1psi, so do i have to keep pumping like crazy? or should it move like instantly?

 

[EclipseTical]

Do you have access to an air compressor or an air tank? it would make life much easier for you.

You'll be pumping forever with that bike pump dude, go hunt down an air compressor or air tank and test away!

 

[daren_p]

ok well, i just got the intake pipe and the MAS out of the way and hooked the tester to my turbo inlet, i just wanted to check if everything was in working order so i used a bicycle pump and pumped say 10 times and my mom said my gauge only moved to 1psi, so do i have to keep pumping like crazy? or should it move like instantly?

You can't do a boost leak test with a bicycle pump, even if you pump like crazy & you have no leaks they don't have enough volume to pressurize the system. You have to hook it up to a compressor and pressurize the system to the boost level your running, first fix all the leaks you can hear, then go around with soapy water and spary down everything looking for more leaks. Once you have everything fixed you should be able to remove the pressure source & the system should hold the pressure, dropping slowly over a min or so. What your trying to do won't tell you anything.

 

[sccrAdidas15]

ok, thx we actually have on of those hand held air compressor to inflate your car tires in the back of my parents car, will something like that work?

 

[oldman]

ok, thx we actually have on of those hand held air compressor to inflate your car tires in the back of my parents car, will something like that work?

Too slow, you need one with a storage tank. Also, did you disconnect your mbc during the test?

 

[sccrAdidas15]

i don't have a mbc.

 

[sccrAdidas15]

i guess i will see if my dad has on at the shop, cause i dont feel like spending 40-50 bucks for one.

 

[oldman]

i don't have a mbc.

Then disconnect the factory BCS.

 

[sccrAdidas15]

well i took the whole mas assembly out of the way so i took it off already. i wonder if i could just go to a gas station and use the air pump there.

 

[kenamond]

well i took the whole mas assembly out of the way so i took it off already. i wonder if i could just go to a gas station and use the air pump there.

The BCS is not connected to the intake except via a vaccuum hose, so you may not have removed it. In a 2g, it's under the coolant overflow bottle, bolted to the passenger side frame rail. It's a small, black solenoid with two hoses coming out the side and an electrical plug on the bottom, connected to the rail with one nut.

Disconnect the hose from the compressor outlet and put a cap on it. The BCS leaks air as part of its function, and you don't want to confuse this with some elusive boost leak.

If you can take your car to your dad's shop (if he only has a stationary air compressor), you could do the test there. Trust me, you'll be very efficient at pulling the intake off in no time. It takes me about 5 minutes to do a boost leak test now on my 2g. Just make sure you can use a compressor with a regulator so that you don't overpressurize your intake to 100psi (this is bad and could blow your turbo compressor seals). Set the regulator to 20psi or whatever you want to test for. You need someone to monitor the boost gauge anyway, so have them read off the levels as you fill and as it leaks down.

I bought an 11 gallon tank for $60, but you could probably find one cheaper. I can do 10 20psi tests with it charged to 80psi even with a minor leak (-1psi/sec) before I have to refill it.

 

[sccrAdidas15]

i thought the BCS was on top of the air canister with two hoses that go into it and a plug and disconnected all that so i just have to put a cap in both the hoses then?

 

[oldman]

i thought the BCS was on top of the air canister with two hoses that go into it and a plug and disconnected all that so i just have to put a cap in both the hoses then?

Yes it's on the air filter housing because you have a 1G. The out fitting should re-route back near the mas and the hose should have been removed along with mas and bcs. The inlet fitting should have a hose coming from a Tee which splits into the turbo outlet pipe and the wastegate actuator. You can go ahead and pinch the end of this hose and zip-tie it for the leak test, this way you can still test the area around the wastegate actuator for leaks.

 

[sccrAdidas15]

ok so i just finished up with the air compressor thing my dad brought home from work, we only did tests up to 10psi b/c he didn't wanna waste all the air since it only had 100 pounds, we found a huge leak by the intercooler it seemed like it was coming from the jbend from the SMIC to the UICP?? There was also some kinda leak near the turbo i wasn't sure if it had something to do with the wastegate or gasket on the LICP i couln't really tell? I don't really know what to do with the intercooler though like take it to a radiator shop? or maybe just go with a FMIC

 

[kenamond]

ok so i just finished up with the air compressor thing my dad brought home from work, we only did tests up to 10psi b/c he didn't wanna waste all the air since it only had 100 pounds, we found a huge leak by the intercooler it seemed like it was coming from the jbend from the SMIC to the UICP?? There was also some kinda leak near the turbo i wasn't sure if it had something to do with the wastegate or gasket on the LICP i couln't really tell? I don't really know what to do with the intercooler though like take it to a radiator shop? or maybe just go with a FMIC

Can you tell if the IC has a hole or if the UICP coupler is leaking?

Did you try spraying things with soapy water? If the leak is bad enough, it won't bubble, but it's worth a try. You can spray down the entire IC, but you have to be able to get at it first. On a 2g, you can jack up the passenger front corner, put a jackstand under it, and reach up between the bumper cover and IC to spray and look for bubbles from underneath, but I'm not sure on a 1g.

Try soapy water wherever you think you have leaks.

Also, make sure you block the BCS line that goes from the BCS and T's off to the J-pipe and wastegate actuator.

 

[Booster-Shot]

All this talk about boost leaks makes me wanna go and do one right now!

 

[sccrAdidas15]

Can you tell if the IC has a hole or if the UICP coupler is leaking?

Did you try spraying things with soapy water? If the leak is bad enough, it won't bubble, but it's worth a try. You can spray down the entire IC, but you have to be able to get at it first. On a 2g, you can jack up the passenger front corner, put a jackstand under it, and reach up between the bumper cover and IC to spray and look for bubbles from underneath, but I'm not sure on a 1g.

Try soapy water wherever you think you have leaks.

Also, make sure you block the BCS line that goes from the BCS and T's off to the J-pipe and wastegate actuator.

yea, it didn't bubble but it was deff. hissing i couldn't really tell it was like coming from the jbend that goes from the intercooler to the UICP like above the jbend or maybe it was that pipe?? I also just put a screw into the hose that goes into the BCS.

 

[kenamond]

yea, it didn't bubble but it was deff. hissing i couldn't really tell it was like coming from the jbend that goes from the intercooler to the UICP like above the jbend or maybe it was that pipe?? I also just put a screw into the hose that goes into the BCS.

I'm a 2g guy, so I'm not familiar with the anatomy of the 1g where the IC/UICP meet. Can you get at it better from above by unbolting the fuse box and filter box and moving them out of the way? On a 2g, you can expose the entire UICP by removing those two parts.

Where is oldman when you need him?