The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Please Support STM Tuned
Please Support ExtremePSI

1G Boost leak check

This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Stock 1G BOV tend to leak both from the IC piping to the outlet and around the shaft. It gets worse as they get worn. In normal use it's not a huge problem since the air goes back into the turbo inlet but it does make the turbo work harder. If it's leaking too much there, just test from the TB to get the rest of the leaks until you can replace the BOV.
 
As long as there is no up and down shaft play and minimal in and out play the turbo should be fine. I would do a boost leak at the TB then do one at the compressor inlet. I would try to go about 20psi with no leaks. The system should be good after that. Like steve mentioned the BOV may be leaking so just feel the outlet of the bov when preforming the boost leak test.to see if that is true.
 
A couple things I can think of. Check the vacuum lines for leaks in the area. Once thing I have always noticed is I have to plug the line that goes to valve cover because it leaks by the check valve. Lastly the compressor cover could be leaking but highly unlikey but worth checking.
 
A couple things I can think of. Check the vacuum lines for leaks in the area. Once thing I have always noticed is I have to plug the line that goes to valve cover because it leaks by the check valve. Lastly the compressor cover could be leaking but highly unlikey but worth checking.

If fills up to about 8psi then it let's go and you hear a quick hissss..

And all the vacuum lines that go to my TB are capped off.
 
Last edited by a moderator:
Are you sure it's not leaking from the tester? Use soapy water

I have did that. Extra bubly. And no bubbles from tester. I figure it to out. It starts filling up fine then at like 8 psi , i i hear a quick psss near turbo and won't fill up anymore then 8 to 10 psi. And when i start my car and look at the boost gauge on the vacuum side it sits at about 8 to 10..
 
I would check all your clamps. Sounds like after 10psi it will leak. Also feel the outlet of the BOV with your hand to see if you feel any air.
 
I will check tommro when I go try this BLT again. That's the only spot in leaking and it must be big because it didn't hold psi.. I'm so cloosee. All summer I've been working on this car getting it back running.. now I narrowed my problem down to this leak.. Thanks for your help.. I will post with what I find..
 
I went over all the clamps and soaked them with soapy water. It's sounds like a gasket or something let's gos at like 10psi. Right in the front near the turbo.

I'd start with the jpipe flange coming off the turbo then. The two bolt stock flanges are notoriously hard to get to seal. Soak it down with the soap and if it bubbles, that gasket probably needs swapped out.
 
I'd start with the jpipe flange coming off the turbo then. The two bolt stock flanges are notoriously hard to get to seal. Soak it down with the soap and if it bubbles, that gasket probably needs swapped out.
I already found that one..
 
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Innovation Products Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top