DarkSlide Turbo II

iTrader: (1)

okay i know some of you guys have answered similar questions about BACs but i cant seem to find exactly what I'm looking for here. Ill start from the beginning; i got my turbo rebuilt for my 87 Tii and started putting it back in the other day. i got it all put back together the turbo worked excellent the engine ran perfect. the only problem was my boost gauge on my pillar pod wasnt working and the digital boost gauge on my boost controller wasnt working. I found that they were both off the same line that runs out of the intake manifold which also runs to my bov. So somewhere along the line of trying to figure out what was wrong with my line one of the guys was pullin vacuum lines off and putting them in different places like crazy while the car was running and all of a sudden it began to idle horribly erratic (1500 - 3000rpm). I went through every single vacuum line i could find and put it back where it goes and it still wouldnt idle right. So as of now my car sits in my garage because im confused. When i start it up it holds about 2k for a while then it drops and starts to surge. I did a voltage test on the bac and my shop manual says it should have around 5 with the key on and the engine off. the reading i got was in the 11 range. Does anyone think the bac is the culprit to my idle horrors, or any other ideas? Also, what can i do with my bac? can i get rid of it completely? and where can i get another one if i need to? Can i just drive it the way it is?

HAILERS2

On the back of the throttle body there are three/four nipples one above the other. ONLY one is vacuum. The very bottom one. The other three are NOT vacuum/boost related. Dig it?

On the right side of the engine there are two places for a boost sensor/guage. One comes off the ACV and the other is located a couple of inches aft of the BAC. Both are good places for a boost gauge.

On the front of the throttle body are three nipples. The Top one is vacuum ( actually for some reason I really don't remember if it's the top or the bottom nipple. If I'm wrong about the bottom nipple, I'll write back.)

By the way, why don't you just look at the diagrams if you want to know if a nipple is vacuum or not?

If you connect the fuel injector air bleed nipple to a source of vacuum, the engine will idle *funny*.

vrracing

iTrader: (1)

So a vacuum line will obvious show vacuum on a vacuum gauge (like if you wanted to test your assertion that the top line of the 3 in front of the TB is vacuum) while a bleed will show positive pressure? Is there a "right" value for the air bleed pressure?

Is there a third class of what we inaccurately classify as "vacuum lines"? I'm thinking of the line from the oil fill that goes to the air intake system with the check value. I'm guessing it would have positive crankcase pressure for which the exact value you dont care about since it is just taking vaporized oil and condensation back around to the front for combustion for pollution control purposes, right?

imloggedin

No. A PCV valve goes to a vacuum line also. Nothing special about it.

imloggedin

lol wow, ive never seen that diagram under any of my hoods. thats better than any of the manuals.