HELP Cant find boost leak *Video*

[le0net]

Hi!

Found some threads covering this, but didnt get an answer, hoping i could get some more ideas here.

Have new injectors, new seals, made a IC tester and connected it before the GM MAF, see picture. When i pressurize up to 4 bar i just hear a hissing from the "backside" of the intake, but cant find a leak, you can hear that in the video.

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Sprayed on soap water and found a leak at the AFR, the threads were leaking so i put some thread tape on, now thats ok, checked all houses, sprayed soap water everywhere but can find the leak.

All tips would be appreciated...

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Big Video

 

[pj91gsx]

check you injector seals. They are in the head. I found out when I installed my injectors I broke the injector seal. good luck.

 

[iluvmy4g63]

Hi!

Found some threads covering this, but didnt get an answer, hoping i could get some more ideas here.

Have new injectors, new seals, made a IC tester and connected it before the GM MAF, see picture. When i pressurize up to 4 bar i just hear a hissing from the "backside" of the intake, but cant find a leak, you can hear that in the video.

You must be logged in to view this image or video.

Sprayed on soap water and found a leak at the AFR, the threads were leaking so i put some thread tape on, now thats ok, checked all houses, sprayed soap water everywhere but can find the leak.

All tips would be appreciated...

Small Video

Big Video

4 bar? thats a little high for a boost test. thats like 56 psi. i would turn it down a bit. also i bet its your intake gasket. it was on mine. would recomend the new magnus heat blocker gasket. best 40$ i spent in a while.

 

[iluvmy4g63]

check you injector seals. They are in the head. I found out when I installed my injectors I broke the injector seal. good luck.

yea. good point. very common spot.

 

[pj91gsx]

I never did a boost leak test but I noticed a hissing noise from around the intake manifold so I decide that I was going to take the whole manifold off. I started by taking off the fuel rail and found my injector seal torn because I was not careful when I installed my fuel rail with the injectors attached. I would check the those seals first. If you see that the injector seals are good then probably take the manifold off. but I dont think an intake manifold gasket would go bad for no reason.

 

[Side_Show]

i had a vacuum leak so i spray carb cleaner around the intake manifold on different spots while car was running, if the rpms raise when u spray it on a certain spot then pretty much found the spot where u are leaking from.

 

[le0net]

I sprayed soap water on the injector seals, and all around the TB, but no leaks, as you can hear in the video the air is leaking very fast, think i need to start take things apart to find the leak..

4 bar should be ok, since im planning on boosting around 2-3 bar...

 

[pj91gsx]

I would just take the fuel rail off. Its only 3 bolts that hold it down plus the bolt on the fuel filter. Also the leak you hear can be from a vacuum line off of the intake manifold. air goes threw all of those lines so check the lines for leaks too. I just assume that you probably broke an injector seal because you installed new injectors. When I installed my injectors I ripped a seal. When did the leak start?

Also, if you take off a gasket on the intake manifold it is important to put rtv gasket on the gasket replace the gasket. Check the TB for leaks.

 

[le0net]

Started to remove stuff, connected IC tester to TB and sprayed soap water on injector seals and everything i can see, no bubbles, reached down as much as i could but could not feel anything, think i need to remove the intake and reseal it..

BTW, does the engine need to be in a "position" so air doesnt go out through the valves? But seems that one of the valves (intake/exhaust) should always be closed so air cant escape that way...

Any more tips before i tear it apart..?!

Leif

 

[le0net]

Ok, intake is off. I had a metallic gasket but no RTV, that was propably the reason for the leakage, didnt find anything else. Will put the intake back tomorrow with some red high temp RTV and hope it seals... What a job, took about a hour to get it off..

L

 

[pj91gsx]

I heard there is a way to adjust the timing so that not as much air will leak but I dont know how to do it.

 

[casperfast]

4 BAR!!!!!??????wow dude, you might have just caused the problem, and the way you have it hooked up your only testing that section of your system, i would put the tester on the compressor intake and hit it with 25-30 PSI 1.5-2 bar. 4 bar is probly enough to blow a manifold gasket which you might have just done

 

[le0net]

This had been ongoing for a while, i could never boost more then 25psi with my 50 trim even if i removed the hose to the actuator, so air has been leaking out a while.

Im running on E85 and planning to boost at least 2bar, so i need to get this sealed. Hopefully the metal gasket with RTV will hold for that.

L

 

[BrokenTsi]

I dont think the thread starter knows what a "bar" is . 1 bar is almost 15psi. 4 bar, would just be crazy.

 

[BrokenTsi]

It could be leaking thru the tb shaft seals.

 

[le0net]

Know i exaggerated with the pressure, but as it was leaking from the first psi, i added pressure when trying to find out where the leakage was, if everything is properly sealed it should hold the pressure, the gaskets are not stock nor the internals.

After putting everything back i will take down the pressure to 2-2,5 bar and test with that.

4 bar = 58 psi

 

[le0net]

It could be leaking thru the tb shaft seals.

Should have seen that with 4bar and soap water?

 

[le0net]

So put RTV on both sides of the gasket, installed it tuesday evening. Took the pressure down to 2bar on my compressor, and STILL THE SAME SOUND.... Tested with soap water but no bubbles anywhere, all hoses are tight and not broken (removed them one and one and put my finger on the hole, but its still leaking.)

Ok, i removed sparks and the air came out from the spark holes, rotated the engine several turns at the same time as i was blowing but it was leaking all the time.. A head job was made before putting the engine together so the valves should seal ok... What am i missing...

HAve anyone experienced this??

Leif

 

[pj91gsx]

did you let the rtv gasket dry for 24 hrs

 

[le0net]

So put RTV on both sides of the gasket, installed it tuesday evening.

Yes, installed it tuesday evening, so it has basically gone more then 36 hours.

 

[le0net]

This should be around 30 ATDC, tested back and forth around that position....

Does this mean that for all cylinders either intake or exhaust valves are closed, or that all valves are closed?

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[The_EE]

One trick to finding leaks you cant see is to use a good sized flexible hose like a stethoscope. Feed the hose into the engine bay and start fishing around for the location of the sound, works well with engine running trying to find exhaust leaks as well. Like like you use for your PCV is good enough, about 4 or 5 feet does it just fine.

 

[le0net]

Thanks The_EE, tested the hose thing, didnt find anything, nothing else to do then take it off again, will screw/seal the intake against something and test it there, shouldt leak... Could still be the intake gasket, its not the injector seals, sprayed them soakwet with soap water, think the metal gasket i had is bad so i need to get a new one.

Stock gasket should hold 2bar/29psi?

L

 

[meliketoball]

Holy moly! 4 bar is super high!

 

[le0net]

Ok, bolted the intake manifold against a wooden plate, sealed with blue RTV this time, tested after one hour, kept 2 bar several minutes until the IC tester popped off, so it seems the red RTV i used yesterday was crap...

Cleaned everything, put back the old metal gasket with blue RTV on both sides, will test tomorrow... Wish me luck..

L