Okay- how did I make this happen? BOV won't open

supraguy@aol

Well-Known Member
Dec 30, 2005
4,239
42
48
Atlanta
Hey guys-
I had mentioned this in passing in another post, but now it's an issue that I can't resolve.
Yesterday I replaced my exhaust manifold and gasket, because mine was cracked.
Anyway, I get it all together, and now the BOV won't vent. Here's what I did/touched in the process:
Removed intake pipe, and hardpipe to TB
removed ps resevoir and bracket
removed turbo
removed exhaust manifold
removed manual boost controller(and did not reinstall, put straight connection back in)

p1611269_1.jpg


In the pictures, you can see that the BOV is connected to the vac line by mostly solid piping- I didn't want to run a soft line that far, as I figured it would cause a decrease in response of the valve. I made sure that the line is not disconnected anywhere.

p1611269_2.jpg

This is the line from the turbo back into the wastegate. The other line is the vac line running from
the power steering pump up to the intake. I verified both ends are connected.

p1611269_3.jpg

I don't know if this would show anything, but it's the focus of where I was doing all the work.

p1611269_4.jpg


The engine in general. I tested the vac pressure to the BOV, and it's around 25in. at idle and when I rev to full and close the throttle. Normally, If I do this, the BOV will open.
During rev(naturally), the vac drops to zero, then returns to 25in. vac when i let off.
I don't know if this is a matter of insufficient vac, or something else. I also removed the BOV and checked to make sure it was not blocked or jammed shut. I really don't know what I could have touched that would affect this system, but maybe I just can't see the forest through the trees, and it's something obvious that one of you might notice right away. Anyway, thanks for looking.

ps- the BOV system that I have, was set up over 4 years ago, and has not been modified since then. I have never, ever had a problem with it's operation until I did this maintainence job, so I have to assume I have overlooked something, and it's not a matter of poor setup or natural malfunction.
 

supraguy@aol

Well-Known Member
Dec 30, 2005
4,239
42
48
Atlanta
Ok- update:

The pressure I read at the BOV was in cm, not in.
My pressure was about 10in.- too low. I should be getting about 19, as that is my manifold vacuum.
So i backtracked to the pipe that comes up vertically out from under the intake manifold, and it was 10in there as well.
Now I'm going to start searching under the manifold to see if there are any loose or broken vac lines down there.
 

supraguy@aol

Well-Known Member
Dec 30, 2005
4,239
42
48
Atlanta
Well, my block to valve cover pipe is fairly new, and as a precaution I checked it, all good. I did find a loose vsv line, so I replaced it, but that changed nothing.
The GOOD news- I found the problem back in my 'work area'. The vac line going into the power steering idle-up valve was NOT on- it only looked like it was, since it was sitting down on the base of that valve, along side the line up to the intake. SO, now I know that if I have a leak on that line(the one that crosses over the lower timing cover), I lose apporxinmately half of my intake vac. pressure(and it idles slightly crappy).
Anyway- glad I got this fixed, along with my crankcase overpressure issue- Found out that the line down into my catch can was blocked, and therefore there was NO suction from the TB port. Luckily, my front crank seal is only PART way pushed out. That's my next project. : )