Mysterious Boost Leak Under Intake Manifold
Oct 2, 2009, 05:44 AM
#1
Mysterious Boost Leak Under Intake Manifold
*Update, see bottom of page 1 for updated information/question.
I recently did a boost leak test, and I can hear air coming out from what seems to be under the intake manifold. A more precise location would be the bottom right side of the IM (from looking into the engine bay).
Has anybody else heard a leak back here? I can get it to 15psi, and then it will drop off after removing air pressure.
One thing to note, is a do have a slight head gasket leak on the back side of the motor. Could the leak be coming from this? My original though was, "if it's leaking oil, then its leaking air". The head gasket leak was caused by a 1x1 head stud install (Pruven Performance).
Thanks for the insight guys.
I recently did a boost leak test, and I can hear air coming out from what seems to be under the intake manifold. A more precise location would be the bottom right side of the IM (from looking into the engine bay).
- I checked the injector o-rings - not leaking
- I checked the egr hoses on the back of the IM - not leaking
- I checked the hoses on top of the IM - not leaking
- I checked the connections around the Perrin fuel rail - not leaking
- I checked the TB Shaft seals - leaking, but makes a different sound when I move the throttle cable, so its not coming from here. (Getting replaced by CBRD w/ Mil Spec Seals)
Has anybody else heard a leak back here? I can get it to 15psi, and then it will drop off after removing air pressure.
One thing to note, is a do have a slight head gasket leak on the back side of the motor. Could the leak be coming from this? My original though was, "if it's leaking oil, then its leaking air". The head gasket leak was caused by a 1x1 head stud install (Pruven Performance).
Thanks for the insight guys.
Last edited by kmcconn9; Oct 3, 2009 at 07:25 AM.
Oct 2, 2009, 08:07 AM
#2
The head gasket is getting replaced here as soon as I can get an appointment with CBRD, so we will find out if this is causing the leak soon enough.
But I wondering if anyone else has run into this issue, or if a leaking head gasket could cause a boost leak.
AFR's are more stable now with the bov and vaccume T leak fixed. It wouldnt even get past 5psi with those leaking...
But I wondering if anyone else has run into this issue, or if a leaking head gasket could cause a boost leak.
AFR's are more stable now with the bov and vaccume T leak fixed. It wouldnt even get past 5psi with those leaking...
Oct 2, 2009, 08:10 AM
#3
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I had the same type of leak and it turned out to be a solenoid under the intake near the TB... I think it was the ERG but that was like 3 years ago so I'm not 100% sure.
a good way to find a leak if you know the general area its in is to pressurize the pipes like normal then wet your hand and stick it back there feeling around for the air. you will feel the air better when your hand is wet then when its dry. hope that helps.
a good way to find a leak if you know the general area its in is to pressurize the pipes like normal then wet your hand and stick it back there feeling around for the air. you will feel the air better when your hand is wet then when its dry. hope that helps.
Oct 2, 2009, 08:14 AM
#4
I had the same type of leak and it turned out to be a solenoid under the intake near the TB... I think it was the ERG but that was like 3 years ago so I'm not 100% sure.
a good way to find a leak if you know the general area its in is to pressurize the pipes like normal then wet your hand and stick it back there feeling around for the air. you will feel the air better when your hand is wet then when its dry. hope that helps.
a good way to find a leak if you know the general area its in is to pressurize the pipes like normal then wet your hand and stick it back there feeling around for the air. you will feel the air better when your hand is wet then when its dry. hope that helps.
Oct 2, 2009, 08:39 AM
#5
I had the same type of leak and it turned out to be a solenoid under the intake near the TB... I think it was the ERG but that was like 3 years ago so I'm not 100% sure.
a good way to find a leak if you know the general area its in is to pressurize the pipes like normal then wet your hand and stick it back there feeling around for the air. you will feel the air better when your hand is wet then when its dry. hope that helps.
a good way to find a leak if you know the general area its in is to pressurize the pipes like normal then wet your hand and stick it back there feeling around for the air. you will feel the air better when your hand is wet then when its dry. hope that helps.
Oct 2, 2009, 08:51 AM
#6
Gotcha. Yea I am 6'6, I dont have small hands either.
So it must be right under the TB then from the sounds of it. I will check it out tonight. I might have to pull off the DC Ti strut bar though, that damn thing is always in the way.
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Oct 2, 2009, 06:42 PM
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check the EGR hoses again. the back side one pops off a lot and is very obvious. the front hose often times stays connected, but the hose itself splits right at the nipple on the EGR. its something that you can't tell without actually pulling the hose off and inspecting it. i've seen this hose split many times. the hoses on the solenoid are a good one to check as well.
Oct 3, 2009, 05:51 AM
#13
check the EGR hoses again. the back side one pops off a lot and is very obvious. the front hose often times stays connected, but the hose itself splits right at the nipple on the EGR. its something that you can't tell without actually pulling the hose off and inspecting it. i've seen this hose split many times. the hoses on the solenoid are a good one to check as well.
The one on the front, I will have to double check.
Thanks for the suggestion
Oct 3, 2009, 06:59 AM
#15
ok, so this is weird, or bad. I am currently doing another leak test, and I think I have pinpointed the leak.
If I put my ear on the top of the valve cover, right by the top right bolt I can hear a leak.
Why/how would the leak be on the inside of the valve cover? Might this have something to do with the head gasket leak on the back side of the motor?
Maybe I should pull the valve cover and try to re-tq the head bolts to 85 ft lbs?
If I put my ear on the top of the valve cover, right by the top right bolt I can hear a leak.
Why/how would the leak be on the inside of the valve cover? Might this have something to do with the head gasket leak on the back side of the motor?
Maybe I should pull the valve cover and try to re-tq the head bolts to 85 ft lbs?