How do I make / buy / use / troubleshoot a boost leak tester? [merged]

[Turbo Monk3y]

All boost leak tester threads are combined here.

i read somewhere maybe the Vfaq about making or buying a boost leak tester of some sort but never found it.... the reason being my acceleration seems slower than normal and all ive done to my stock car so far is take out the air box put on a K&N filter and cut the dump tube i have my boost guage sitting in a box not hooked up yet. and since those 2 mods it when i go wot on the car i can hear the turbo spool up and it sounds nice but i can also hear a sound as my rpm increases the SHHHHHHHHHHHHHHHHHHHHHH sound does too. the sound comes from the same area as the BOV i think maybe i got a #@%#@%#@%#@% stock bov and it cant handle over 11-13 psi??? Then i shift and it makes the nice BOV sound WHOOOOSHHHH... but my car seems to be a little slower.. any ideas before i go check every tube clamp and tube????

 

[bboyxtac]

hello everyone, today i performed the test on my car and found that i have a pretty bad leak around the throttle body and a small leak around the bov. my problem is that my car will fall on its face @ 4-5000 rpms and will shake badly. will replacing these gaskets answer my problems. any info will b greatly appreciated thank you.

 

[karbon]

I posted in another thread in this area regarding throttle body leaks a few minutes ago. Check it out.

 

[guamgsx]

I just did the same test on my car but my car would not build boost. But, I found air coming out of my vavle cover breather tube. Did yours do that?

 

[Mits3gts]

hehe i just did a leak test also,but could only build 1 psi,is there anything that should be blocked off to do a test? funny thing is my car makes 10psi,and 22in.hg at idle.car is basically stock.

 

[Mike000]

I just did the same test on my car but my car would not build boost. But, I found air coming out of my vavle cover breather tube. Did yours do that?

Your PCV is leaking. Get an OEM one. Aftermarket (part sorce) all leak from the start.

 

[Defiant]

i also think my car is running lean bcause spark plugs are white.

Plug readings are just about worthless in the world of closed-loop feedback fuel injection.
They weren't that helpful with double-pumper Holleys, for that matter. You need to chop the motor off at its best output, and the trouble is that the flywheel and crank mass keeps things running even without spark, destroying the precious tan residue you're hoping to find.

If nothing's melted, wet or broken, ignore what the plugs look like.

 

[CyberEye]

hello everyone, today i performed the test on my car and found that i have a pretty bad leak around the throttle body and a small leak around the bov. my problem is that my car will fall on its face @ 4-5000 rpms and will shake badly. will replacing these gaskets answer my problems. any info will b greatly appreciated thank you.

Sounds exactly like what my car is doing. Only difference is I can't get my damn intake leak tester to work

Why not just fix the two leaks and see if that helps?

 

[civickiller]

how can i do a boost leak test. I never done one before.

 

[1993eclipseGS]

Like this : http://www.vfaq.com/mods/ICtester.html

 

[blcknspo0ln]

there's two ways i've found to do it.

the VFAQ way, where you put the air through the little tester you make or you can block off the turbo inlet [ they used a can and a coupler ] and tap into a boost source.

either way should work.

 

[CyberEye]

Okay, what the crap. The first intake leak tester I made wasn't quite big enough to fit on the turbo without some fuss, but I got it on. When I put air into it, I could hear the air getting into the system, but my boost gauge wasn't moving.
I made another one that fits better, tried it yesterday and same thing happened, when I put air into the system the boost gauge doesn't move, so I have no idea how much pressure I'm putting on my engine.
I took the UICP off the throttle body an I can hear/feel the air coming out of it, so the air is definately reaching the intake manifold, so I don't see why my boost gauge isn't seeing pressure.
Both times I was using a big shop tank/compresor, so there should be no problem about not putting enough pressure into the system.

Any ideas why I wasn't seeing pressure at my boost gauge ( i had someone sitting in the car while I was putting air into it). How long of standing there with the air hose on it should it be before the boost gauge moves?

 

[Tsi_User]

stock or aftermarket boost gauge?

 

[CyberEye]

stock or aftermarket boost gauge?

aftermarket, t'd into the vac line for the fpr solenoid, between the solenoid and intake manifold.

 

[oldman]

Do you hear air leaking out any where? Disable the mbc, it could be leaking so fast that you can't build pressure fast enough. Bring the motor to TDC so all the valves are closed. If the boost gauge work fine before you must have a big leak some where, that includes the tester you made.

 

[Staytuned]

Yes bring your #1 piston to TDC. I tried a leak test the other day and I had a pair of valves open with a bit of overlap and the air was going out the exhaust valve as fast as I could put it in.

 

[dsm4life]

Ok i disconnect the MBC and have the waste gate line ran "T" ed into the BOV line into the TB. The only lines that are disconnected are the BOV dumptube side, charcoal canister line and oil breather line from Valve cover. Would any of these lines hinder my ability to build boost ????

I have my dad compressor hooked up and it reads in lb/in^2 How much of that would be needed to build boost ? i haven’t gone past the 60lb /in^2 yet. So far my boost gauge shows 0 ???

 

[JessesTalon]

If your pcv valve is disfunctional that could be a problem in a boost leak test.

When my pcv valve went haywire all the boost pressure was blowing my oil out of the valve cover.

 

[dsm4life]

one other question , with a 16G is the turbine wheel harder to spin then the stocker t25 ?? The wheel seems to spin freely (not hitting anything) but if i kind of "throw " the wheel with my finger it doesnt cont to spin .. is that bad ????

 

[oldman]

1. Bring #1 cylnder to TDC so all intake valves are closed, make sure you don't turn the crank ccw.

2. If you're not sure how old you pcv valve is, diconnect the hose from the intake manifold and cap off the nipple.

you want to pressurize the system to at least 20psi. If you're unable to build boost then something is leaking pretty bad. Don't go by the gauge on the compressor, use your boost gauge instead. Some of those line you disable is fine as long as what needs to be capped off is capped off. Follow the diagram here and make sure the removal of vacumm lines were done properly.

http://www.taboospeedshop.com/emissions1.htm

 

[dsm4life]

1. Bring #1 cylnder to TDC so all intake valves are closed, make sure you don't turn the crank ccw.

2. If you're not sure how old you pcv valve is, diconnect the hose from the intake manifold and cap off the nipple.

you want to pressurize the system to at least 20psi. If you're unable to build boost then something is leaking pretty bad. Don't go by the gauge on the compressor, use your boost gauge instead. Some of those line you disable is fine as long as what needs to be capped off is capped off. Follow the diagram here and make sure the removal of vacumm lines were done properly.

http://www.taboospeedshop.com/emissions1.htm

"Bring #1 cylnder to TDC so all intake valves are closed, make sure you don't turn the crank ccw"

How do i do that sorry ?????



i am searching for how to bring cylnder to TDC but if you can tell me would be great. Im getting pressed for time now.

 

[oldman]

"Bring #1 cylnder to TDC so all intake valves are closed, make sure you don't turn the crank ccw"

How do i do that sorry ?????



i am searching for how to bring cylnder to TDC but if you can tell me would be great. Im getting pressed for time now.

1. TDC (top dead center): Remove the plug from #1 and insert a long extension down the hole. Turn the crank by hand (via manual) cw until the extension doesn't move up for down.

2. There should be two gauges on the compressor, one shows what's in the tank and the other shows what's the max psi to be pumped into the system, either tells you precisely what is currently in the system, only the boost gauge does.

 

[dsm4life]

ok i put the ext in the hole and cranked it ,it went up and down puffing air then was really hard and stoped. After it became really hard to crank and the ext wasnt moving anymore i stop. turn compressor on and still ZERO boost ?????????????????

 

[steve]

1. Bring #1 cylnder to TDC so all intake valves are closed, make sure you don't turn the crank ccw.

I'm pretty sure that at TDC as indicated on the front cover the intake valves are not all closed. My logic is as follows:

When the mark on the harmonic dampner is aligned with the 0 on the front cover, cylinder 1 should be at TDC compression stroke and all the valves have to be closed in this cylinder. Actually the the front cover just shows crank TDC so you don't know if cylinder 1 is at TDC compression or TDC exhaust without looking at the cam timing marks, but let's assume we are at TDC compression on #1. Cylinder 4 is 360 degrees out of phase with cylinder 1, it's at TDC of the exhaust stroke and this is the interesting place. If we were 306 degrees off the it's cylinder 1 that is in overlap.

The intake valves open at 26(NA) or 21(T) degrees BTDC and the exhaust valves close at 9 degrees ATDC during the exhaust/intake strokes. So cylinder 4 both sets of valves are open during this roughly 30 degree time called valve overlap. Cylinders 2 and 3 are both at BDC in their various strokes and have at most one set of valves open.

This is why I suggest pressure testing the intake with the crank at about 30 degrees before or after TDC so that at most there is only one set of valves open per cylinder.


Steve

 

[thegreatms]

When i do a boost leak test I crank the cylinders until they are all at equal height. But a equal lenght extension in #1 and #2 then crank until they stick up the same amount. then put your spark plugs back in. this way you know that none of the valves are in overlap.

Also you can test your intake path in stages: from turbo to BOV; then from turbo to IM elbow. Then i just do from the IM on. this way you can figure out what part is leaking worst and fix it first.

I often find a couple tiny leaks that don't seem to be a big problem, and then one or more large leaks that are affecting performance

 

[dsm4life]

Ok i got most of the leaks. Few intercooler pipes and the BISS screw.. Thanks guys butttttttttttt

i am still having a leak but the car is running ok with the leak. No longer running rich and builds boost again !

When i pump the hand pump i was using i can still hear hissing right behind where the BISS screw is. I killed the area with soapy water but still i cannot find it. What can it be back there ???? and like i said KILLED it in water. Pumped up and got no bubbles what so ever