we installed the fmic today and were almost 100% positive there are no boost leaks but when i rev it up if it stays in vacuum it revs up fine but as soon as it hits positive boost it just stutters

we think it is the vacuum line that used to go to the stock intercooler at the top we left it unplugged then we plugged it up but nothing what the hell do we do to it?

 

 

i used it for my BOV, but you can plug it.

 

The tube on the right aft end of the intercooler, is for the air feed for the Air Supply Valve (first picture). The fsm describes the function of the Air Supply Valve. Fuel section.

The tube on the intercooler that is on the right outboard side is for the Air Bypass Solenoid.

That applies for a series four turboII. If it's a series five, disregard and read the fsm for series five.

 

It doesn't connect directly to the plenum, so your BOV won't be doing much...

Hailers is half right. Both of the those nipples are for the same thing. They are normally connected together by a hose. The ASV is on the back of the plenum, and is basically a throttle bypass that connects the IC to the plenum. The ASV opens to increse idle speed when the power steering is used or the hot-start assist system is active.

If it were my car, I'd add a nipple to the IC piping just before the TB and connect it up to the ASV.

 

Hailers is 100 percent right if that was a series four. On a series four the intercooler has two nipples. One on the right aft end and one on the right aft outboard side. The first for the air supply valve and the other for the air bypass valve.

I did catch that remark about using the nipple in the first picture for a bov, but just ignored it. That is a most unsatisfactory place for a blow off valve . I got a chuckle out of that placement.

EDIT: Oh. Public Profile says you have a series five. Ditch the series five and buy a series four and my answer fits to a tee.

 

eh it went whoosh so i guess it was working.

 

how is the BOV set up on this IC project, that would be the first place i would start troubleshooting a boost problem.

 

ok the motor is a series 4 i dont know why there is only one nipple but i made my own piping and it has a greddy type s and i blocked off this nipple coming out of the plenium but it wont get boost it just stutters like a bad leak i searched these pipes for hours no leaks i think this nipple has something majior to do with it

 

so what do i do with it do i cap it off?

 

if it didn't make a difference when it was capped then i would pretty much guarantee it is not the majority of the problem but it should either be sealed or run back into the inlet piping.

are you sure your BOV isn't stuck open and bypassing the air to atmosphere or recirc system?

 

so you doublew checked all the couplers? and lines?, put the stock intercooler on and see if it still does it, you probley ahve a vac line upluged somwhere, you mess with the TID at all? even if you didnt its stlil easy to pump lose off the turbo inlet if you have the stock one

 

i have a hks up pipe that came from the turbo to the intercooler but it is switched over instead of flowing one way it flows another but i dont see how that hurts it all i did was changed the direction could this affect it?

 

U can try rigging up a boost leak tester.. I used to use it for my DSM all the time, no matter how tight u think it is.. u never know...

 

Then you must have it connected somewhere else. The nipple in the pic does not ever see vacuum, it leads straight to the ASV.

 

well i figured out the problem there was a leak somewhere so it fouled out the plugs from running soooo rich but now i got new plugs and im running the stock top mount but it still kinda hesitates ill have to see if it goes away

 

I'm having the same problem. Where was the leak that you found? I'm interested if it goes away too.

 

can you remove the ASV?

 

If you want, but I wouldn't recommend it if you have power steering.

 

oops i meant the air bypass solenoid valve, it looks almost like it. Mine broke

 

Ah, so you mean the AWS? That should be removed even if it works fine. All it does in increase engine wear...

 

NICE. what should i cap off or plug up

 

Whatever you disconnect.