Throttle body air leak...Pics inside with how to fix!!!
I'll be pulling the throttle body off my '03 with 81k on it this week. I am going to borrow a friends boost leak tester. Wonder if this could have contributed to my idle air control valve failing four months ago?
I might have the same problem. I can turn the tester up to 20psi and my boost gauge reads 4psi. I turn it up to 30, it reads 6, turn it up to 40 and it reads 8. Is this what those of you who said you can't hold past 3-5psi mean?
Also, I don't hear anything around the tb, but the pressure is running straight out the back through the exhaust. Is this a tb issue or something else?
I have alky so I've run 26psi tapering to 19 and 28psi tapering to 20psi. Normal or too much taper? Thanks!
Also, I don't hear anything around the tb, but the pressure is running straight out the back through the exhaust. Is this a tb issue or something else?
I have alky so I've run 26psi tapering to 19 and 28psi tapering to 20psi. Normal or too much taper? Thanks!
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.
.
BTW for reference, I have 57,000 miles on my 2005. I did a boost test at 52k and there was no leaks, now at 57 it is leaking like crazy. Damn it.
Last edited by Soon2BEVO; Aug 23, 2006 at 12:08 PM.
Originally Posted by Soon2BEVO
Wow thats exactly what happened to me, good find!
BTW for reference, I have 57,000 miles on my 2005. I did a boost test at 52k and there was no leaks, now at 57 it is leaking like crazy. Damn it.
BTW for reference, I have 57,000 miles on my 2005. I did a boost test at 52k and there was no leaks, now at 57 it is leaking like crazy. Damn it.
It made me feel even better that it turned out to be something
useful to the Evo community.
This turned out to be a very informative and important thread.
57K on your 05 allready ... WOW !
Making it to 52K with out any leaks is very good.
At least with this thread, you wont have to spend a small fortune
for a new throttle body.
Thanks to dbdude for originally posting this thread and pointing out the leak.
Thanks to nigletsyz for all his time, hard work, taking pictures and sharing
his information with us.
Checkout this thread ...
https://www.evolutionm.net/forums/sh...3&page=3&pp=15
https://www.evolutionm.net/forums/sh...3&page=3&pp=15
Originally Posted by Spec'd
Checkout this thread ...
https://www.evolutionm.net/forums/sh...3&page=3&pp=15
https://www.evolutionm.net/forums/sh...3&page=3&pp=15
Originally Posted by dbdude
Its crazy how alot of us did not know about this leak.
Thanks to you and nigletsyz , this thread will save of us some grief and money.
It's great.
Well I was was able to get off of work early today and performed the leak test. I'll be damned, a major leak from the throttle body. I couldn't keep at more than 5 PSI before the hissing started. If I played with the throttle a little, I was able to stop the hissing but as soon as I let go of the lever the hissing came back. I was wondering why my idle was a little unstable for the past several months and now I know why. I had recently checked the plugs, plug wires, and coil packs and they were fine. It's now time to order those seals and fix it. There should be a recall from Mitsubishi concerning this issue.
Last edited by EvoTio; Aug 23, 2006 at 07:51 PM.
Hi,
We got confirmation recently that these seals DO fit perfectly into the Evo throttle body. Honestly, I'm surprised that cars this new are having problems with this. I don't remember any DSM's with leaky throttle bodies at three years old. At least it's relatively inexpensive to fix.
I've added the seals to our Evo web site, so hopefully you can add a T-shirt or another Evo trinket to your order and amortize the shipping over a couple of items.
As always, thanks for your business.
--Dan
Mach V
MachEVO.com
We got confirmation recently that these seals DO fit perfectly into the Evo throttle body. Honestly, I'm surprised that cars this new are having problems with this. I don't remember any DSM's with leaky throttle bodies at three years old. At least it's relatively inexpensive to fix.
I've added the seals to our Evo web site, so hopefully you can add a T-shirt or another Evo trinket to your order and amortize the shipping over a couple of items.
As always, thanks for your business.
--Dan
Mach V
MachEVO.com
Originally Posted by Evoisdream
i also found out that napa can for sure get them with that 3090 number