Throttle body air leak...Pics inside with how to fix!!!
Jul 4, 2006, 04:39 PM
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Throttle body airleak...Pics inside with how to (someone sticky this!!!)
I decided to check for boost leaks and i found some. I connected my tester straight to the air intake maniold and started pumping. There was a loud hiss coming from the 1st fuel injector. As you can see in the pic, the black O-ring is not mounted properly so i took care of it. Now i hear a hiss coming from the throttle body. When i pull the throttle cable, the hissing changes tones. As you can see in the pic i pointed at the area with green arrows. Im not sure if there is anything i can do besides buying a new one and hope that it dont leak either. Is there any adjustment like a screw or gasket that takes care of it? Im only making about 5psi at the manifold leaking very slowly. Have any of you guys ever tested this area? I also checked all the other IC pipes and everything held up to 20+psi. Dont just read. Please help. Im sure many of you evo owners have this problem but dont know about it. 
Jul 4, 2006, 04:48 PM
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That's a good way to test for leaks.
At least you narrowed the problem down.
That can often be the hardest part, finding the leak.
My car has low miles and slightly modified, so I haven't experienced leaks yet.
Can't your existing throttle body be rebuilt ?
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At least you narrowed the problem down.
That can often be the hardest part, finding the leak.
My car has low miles and slightly modified, so I haven't experienced leaks yet.
Can't your existing throttle body be rebuilt ?
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Jul 4, 2006, 05:40 PM
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Originally Posted by evodan2004
y did you do it from there. you should of done it right from the turbo. that way you get the hole system checked. how many psi you running. i did 25 and got all my leaks fixed.
Jul 4, 2006, 05:45 PM
#5
Originally Posted by dbdude
Im running 22psi. The throttle body is the only leak i have now. From the turbo all the way up to that point holds over 20psi. Maybe the throttle body can be rebuilt. Im wondering if its hard to take off just the throttle body without having to take out the whole manifold. Has anyone one here done this before? How much is a new throttle body or does anyone make an aftermarket one?
Jul 4, 2006, 05:47 PM
#6
also taking the t/b off is not hard. just take your time and remember where everything went when you put the new one on. but if i may ask why do you need a new one in the 1st place. you do know the t/b is not air tight?. when doing a boost test air will get by. also you can do it with the t/b open.
Jul 4, 2006, 06:02 PM
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OK.. So let me get this straight. Everyone here that does boost leak tests has an air leak at the throttle body when the procedure is done like i have in the pic?? I tested the rest of the IC pipes after i put evarything back together of course. But i put a plug on the upper IC pipe before i connected it to the throttle body or else my psi would only read about 5psi cus of the TB. I thought the throttle body was suppost to be airtight. So if you started checking at the turbo then did you block off or put a plug at the end of the upper IC pipe to get the high psi reading??
I just reread your post and understood you better. I know air gets by inside the throttle body even when its closed. You said it can even be open and you can still do a test. I tested it even when its open and i can still hear a hiss and see the psi drop slowly. You know how the inside looks with a circular plate that moves half way when the throttle is open, I think the air is escaping thru the metal peice that goes from the inside of the TB to the outside of the TB where the cable pulls.
I just reread your post and understood you better. I know air gets by inside the throttle body even when its closed. You said it can even be open and you can still do a test. I tested it even when its open and i can still hear a hiss and see the psi drop slowly. You know how the inside looks with a circular plate that moves half way when the throttle is open, I think the air is escaping thru the metal peice that goes from the inside of the TB to the outside of the TB where the cable pulls.
Last edited by dbdude; Jul 4, 2006 at 06:09 PM.
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Jul 5, 2006, 05:47 PM
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Originally Posted by dbdude
bump...
Maybe they can help. I am curious about this now myself.
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Jul 5, 2006, 05:55 PM
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I found this ...
http://ca.dsm.org/FAQ/tb-shaftseals.html
As you provide pressure into the system, you will hear it leaking from this general area. If you then manually rotate the throttle plate (or have the buddy in the car step on and off the gas) you will hear the sound changing. This is the leak around the shaft seals.
The problem with these things, is that they're simple rubber seals, bonded to a metal ring. Over time, the rubber they used, gets tired from the heat, oil, etc, that it's exposed to, and just goes rock hard. As you'll see later on, the residue it leaves on the shaft as it's breaking down is terrible to try and remove. The rubber is now like hard plastic, as you will see if you go on to dissect it. They were likely not ever even thought of as much of a problem in design, as they're definitely a long-term wear item that most customers would never notice.
So, assuming you have purchased a pair of 14mm x 10mm x 4mm (or 3mm) shaft seals, and are ready to proceed, let's get going.
.
http://ca.dsm.org/FAQ/tb-shaftseals.html
As you provide pressure into the system, you will hear it leaking from this general area. If you then manually rotate the throttle plate (or have the buddy in the car step on and off the gas) you will hear the sound changing. This is the leak around the shaft seals.
The problem with these things, is that they're simple rubber seals, bonded to a metal ring. Over time, the rubber they used, gets tired from the heat, oil, etc, that it's exposed to, and just goes rock hard. As you'll see later on, the residue it leaves on the shaft as it's breaking down is terrible to try and remove. The rubber is now like hard plastic, as you will see if you go on to dissect it. They were likely not ever even thought of as much of a problem in design, as they're definitely a long-term wear item that most customers would never notice.
So, assuming you have purchased a pair of 14mm x 10mm x 4mm (or 3mm) shaft seals, and are ready to proceed, let's get going.
.
Jul 12, 2006, 08:37 AM
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Originally Posted by Spec'd
I found this ...
http://ca.dsm.org/FAQ/tb-shaftseals.html
As you provide pressure into the system, you will hear it leaking from this general area. If you then manually rotate the throttle plate (or have the buddy in the car step on and off the gas) you will hear the sound changing. This is the leak around the shaft seals.
The problem with these things, is that they're simple rubber seals, bonded to a metal ring. Over time, the rubber they used, gets tired from the heat, oil, etc, that it's exposed to, and just goes rock hard. As you'll see later on, the residue it leaves on the shaft as it's breaking down is terrible to try and remove. The rubber is now like hard plastic, as you will see if you go on to dissect it. They were likely not ever even thought of as much of a problem in design, as they're definitely a long-term wear item that most customers would never notice.
So, assuming you have purchased a pair of 14mm x 10mm x 4mm (or 3mm) shaft seals, and are ready to proceed, let's get going.
.
http://ca.dsm.org/FAQ/tb-shaftseals.html
As you provide pressure into the system, you will hear it leaking from this general area. If you then manually rotate the throttle plate (or have the buddy in the car step on and off the gas) you will hear the sound changing. This is the leak around the shaft seals.
The problem with these things, is that they're simple rubber seals, bonded to a metal ring. Over time, the rubber they used, gets tired from the heat, oil, etc, that it's exposed to, and just goes rock hard. As you'll see later on, the residue it leaves on the shaft as it's breaking down is terrible to try and remove. The rubber is now like hard plastic, as you will see if you go on to dissect it. They were likely not ever even thought of as much of a problem in design, as they're definitely a long-term wear item that most customers would never notice.
So, assuming you have purchased a pair of 14mm x 10mm x 4mm (or 3mm) shaft seals, and are ready to proceed, let's get going.
.
Jul 25, 2006, 10:10 AM
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I will tell you an easy way of finding leaks at the throttlebody or intake: Just get a can of spray carb cleaner and spray around the area in question while the car is running (at idle). As long as you have all of the hoses and pipes connected, the spray should have no affect on anything. If there is a leak, the engine RPM's will change immediately when you spray in that area. You can really pinpoint an intake leak this way. Might want to wash the motor off a little bit after doing this if you got carried away with it. It doesn't take much to find any leaks...
