Bad boost leak test results, consistantly, on a 99GSX

[Jammin'Trey]

Hey guys, I have a 1999 eclipse gsx, ever since I got the car I have never been able to have good results doing boost leak tests. I can't get the car to hold any boost for any period of time, as soon as I release the pressure to the system it leaks out. I have eliminated all the leaks in the inter cooler piping and throttle body. I consistently get a leak coming from the valve cover breather. To my knowledge there is 3 main ways that boost enters the crank case, 1. bad rings, 2. bad turbo seals, 3. bad valve stem seals.

Today I did a compression test, cam up with 175 across the board, this was a dry test, then I put a tablespoon of oil in each cylinder and retested, I got 175 across the board again..... I believe this eliminates bad ring seal

test 2, I did a boost test at the throttle body elbow, results came up the same as always, still leaking boost out of the valve cover, I believe this eliminates bad turbo seals (turbo never pushes out any oil into my intake or exhaust as well)

test 3, I put the engine at TDC, center two cylinders, I did the boost leak test pre and post turbo, same results, boost escapes out of the valve cover.

The only test I haven't done is a leakdown test, I dont own a leak down tester, and to buy one that is accurate is a lot of money.


Any input? I am at a lost, I can hear oil gurgle when I do the BL test from the throttle body, but not from the turbo? Thanks a lot in advance, hopefully I can get this figured out.

 

[LTUDSM]

Why you just dont use the magic 'Search' button took me 2 sec and thats what i came up with

Boost Leak!! Valve Cover Breather

Did a boost leak test, valve cover leaks???

Boost leaks in Odd Places

 

[gsxofftheline]

Sounds like the PCV is not working properly. Even the ones from mitsu suck. just get a check valve at autozone for 2 bucks and put it between the intake mani and PVC valve on the valve cover. I had the same thing when i first bought my 2g gsx aswell, went through two $12 mitsu PCV valves untill I got a check valve, they rate to 50 psi too. Hope this helps.

 

[habitatguy187]

^^^ Very correct. Although I use this check valve. Holds to 150 psi.

Make sure you keep the pcv valve that's in there though, as it acts as a metering orifice. If you completely get rid of it you will idle badly, and if you block it off and just use the pcv you will leave gasses in your crankcase therefore breaking down your oil.

 

[gsxofftheline]

^^^ Very correct. Although I use this check valve. Holds to 150 psi.

Haha yeah I've heard of those, but they are not neccessary. I actually bought two at the time and I hooked one up to a compressor and I regulated the pressure to 125 psi and it shot out haha.

 

[gsxofftheline]

^^^ Very correct. Although I use this check valve. Holds to 150 psi.

Haha yeah I've heard of those, but they are not neccessary. I actually bought two at the time and I hooked one up to a compressor and I regulated the pressure to 125 psi and it shot out haha.

 

[gsxofftheline]

^^^ Very correct. Although I use this check valve. Holds to 150 psi.

Haha yeah I've heard of those, but they are not neccessary. I actually bought two at the time and I hooked one up to a compressor and I regulated the pressure to 125 psi and it shot out haha.

 

[Jammin'Trey]

Pcv is in great shape, holds pressure no problem.

 

[Jammin'Trey]

Why you just dont use the magic 'Search' button took me 2 sec and thats what i came up with

Boost Leak!! Valve Cover Breather

Did a boost leak test, valve cover leaks???

Boost leaks in Odd Places

I read through every one of those threads extensivly, I couldn't find a diagnosis for the problem. I have had bad test results. I think i am going to borrow a leakdown tester and try that. Hopefully I just need rings.

If I do need to put new rings in the 7 bolt should I just do a quick hone, new rings(clean landings...) and rod bearings.... Dont even touch the crank main bearings? Thanks in advance

 

[My1GLaser]

Like said many times. PCV VALVE. Just block the port on the IM and do a test to take it out of the equation and the air coming out the breather should slow down a lot.

Some air out of the breather is normal. Any partially open valves let air into the CC which goes past the ring end gap even if the rings aren't worn out.

 

[Jammin'Trey]

I will go check the pcv by hooking it up to my air compressor

 

[Jammin'Trey]

the pcv is leaking a small amount, not quite as much as whats coming out of the valve cover.... will get a check valve asap

 

[gsxofftheline]

Yeah and let us know the results of the test. You said just rings? haha wish it was that easy. Have you done a compression test? That would determine if the rings are bad or not.

 

[Jammin'Trey]

did you even read my first post? I have done wet/dry compression tests, both were 175 across the board.... I tried doing a BL test before and after the turbo, both times air still comes out of the valve cover...

 

[donniekak]

Block off the pcv at the manifold and test from the throttlebody.

 

[gsxofftheline]

did you even read my first post? I have done wet/dry compression tests, both were 175 across the board.... I tried doing a BL test before and after the turbo, both times air still comes out of the valve cover...

Oh that's right, my bad. But you metioned that it could be the rings and it wouldn't be a problem, I just figured that if you did the compression test then you would void out the piston rings.

 

[gsxofftheline]

And a side note, when you replace the rings, you wouldn't just replace the rings, you got to rebuild the block. If you just replace the rings, your just covering up the problem.

 

[habitatguy187]

Have you tried doing a boost leak test with the car warmed up?

 

[Jammin'Trey]

Yes I have, same results hot or cold.... I am thinking its valve guides/rings... I am doing a leakdown test as soon as I can borrow a good tester....If it fails the leakdown test I am going to most likley get the head rebuilt and put new rings (am=nd glazebreak/hone) the cylenders....

 

[TastyTalon]

Yep my bet is the rings. A fresh rebuild would eliminate tons of problems and then you'd be good to go!

 

[ShadyGST]

^^^Wow thats a first! I never heard anyone suggest a engine rebuild due to boost leaks!

 

[habitatguy187]

Block off the pcv at the manifold and test from the throttlebody.

Have you done this yet?

 

[Jammin'Trey]

I put a check valve on the pcv, I will retest, the pcv shouldnt be leaking but I will try...

 

[habitatguy187]

I put a check valve on the pcv, I will retest, the pcv shouldnt be leaking but I will try...

You also shouldn't be getting blowby with the compression you mentioned.

 

[JEFFREYCASTGSX]

Leakdown test(it will lead you closer to the problem)?............ You say you keep having these problems? The symptoms for what seem to be a boost leak, might actually be something else.