3SGTE Help - Boost Leakage

[cjrasmu]

Hey all,
I have a problem with my recently upgraded ST185.
It won't boost past 0.6 bar, and if I try, it starts misfiring in the higher revs. I have a ProfecB Spec2 hooked up and set correctly. It was boosting nicely before I got my BOV plumbed-back, but that seems to be hooked up ok.
I have checked all the clamps and they seem to be secure. And I cant find any holes or cracks in any of my pipes or silicon.
Here is a pic of my engine bay. If you have any ideas on what is causing my problem, please help me.



Cheers,
C.j

[Bored?]

In the rubber elbow after the AFM there is a line running back toward the plenum (probably idle air or something, possibly a factory BOV. It looks like it is missing at least one clamp in the photos. Also, immediately below that line in the rubber elbow appears to be an entry point for another line (hard to tell in the photo though). If that line isn't blocked, it would cause your AFM to read incorrectly.

Also, there is a blue vacuum line running toward the front of the engine bay. Is this connected to the BOV?

[cjrasmu]

The blue pipe is connected to the EBC. And I have no idead what you are talking about with the elbows. All the pipes to and from the elbows are connected properly.
Cheers,
C.j

[Squid]

A small piece of hose can be used as a stethescope, stick one end in you ear and point the other end around the engine, it is very directional, so useful for finding leaks...

[Bored?]

Also if you don't hook a vacuum line to your BOV it's going to suck. It should be opened by applying vacuum from the plenum when the throttle is shut, not just pushed open by excess boost. This also means that boost in the plenum will hold the BOV shut so it doesn't leak under boost. If that line is missing, it would explain a lot.

[cjrasmu]

The black hose running vertically over the top of the right hand side of the engine is the vac line for the BOV.

[cjrasmu]

Another Pic

[sw20r]

check for restrictions in your intake especially the cold air feed section. I had a flexiable hose that got blocked while driving so i lost boost pressure.. felt like my turbo had just dropped

[cycleofabuse]

I was playing around with some vacuum hoses one day and made it so my 3sgte wouldn't boost past about 6psi as the BOV would open. I still don't know why the vacuum hose set up didn't work but it definately caused a lot of leaking. Does it sound like it's leaking out of your BOV? Or does it not really make a sound when it struggles to get past 0.6 bar? Have you got a stock TMIC to chuck on and see if it does the same thing?
Good luck.

[cjrasmu]

I cant hear any different noises at 0.6 bar, but it could just be getting drowned out by exhaust etc.
And no, i dont have a stock TMIC to throw on, apart from the fact I wouldn't want to cause it would be a pian in the ring.
I tried adjusting the spring on my BOV to its hardest, but that made no difference. It is a plumback too, so it would be hard to tell if it was the problem.
Although, like I've already said, it was boosting to 1 bar when the BOV was just venting to atmosphere.
Cheers for help so far,
C.j

[cycleofabuse]

Do you have a vacuum line running to your BOV? This will keep it closed when on boost.
If it was working fine before when it was venting to the atmosphere, you'd think that the BOV, or where it connects is leaking.

[Matty P]

You don't seem to be running the EGR assembly. Have you made sure that it is blocked off properly?

[cjrasmu]

JDM = no EGR

[Alchemist]

Leakage aside, nice exhaust and turbo setup. Sorry I can't offer any advice, but just saying

[cjrasmu]

Problem solved. Was the spark plugs. The ones I had were set at the wrong gap and couldn't be adjusted. Just got some NGK ones and now it goes to 12psi. Yay!
Cheers,
C.j