Greddy Blow off valve

[ScottyStyles]

I've been getting a lot of compressor surge lately, and I finally decided to fix it at bcool's urging. So, I got into my blow off valve and found a few things.

First; the previous owner had the thing as tight as he could crank it, so it had no possibility of opening. That's an easy fix... just had to replace the all-thread bolt and nut that had literally rusted together, and had now become worthless. Got that done, and played with how loose I needed it. Even as loose as possible, it still wouldn't open.

While I had everything apart, Greg and I noticed that the rubber flange... thingy was looking worn, and had some holes in it. Would that prevent the bov from working? Is there anything else I can do to try and get this goofy thing working?

[cupcake]

If it had a hole in the valve, that could do it. Without vacuum, it won't open.

[Gregory]

Should have taken a picture of it to show how worn out the rubber diaphragm looked and yeah it did have tears in the diaphragm.

[bcool]

Yep you're going to need to find another diaphragm. Without an air tight seal that sucker isnt going to open.

[ScottyStyles]

Yep you're going to need to find another diaphragm. Without an air tight seal that sucker isnt going to open.

Any recommendations on where to get one? Can just the diaphragm be replaced easily? It didn't look like a removeable part.

[Gregory]

That has got to be the most fucked up BOV in the world. Scott and I replaced the BOV with a new one and it works, however the car refuses to idol and dies. But when we replaced the new cap with the cap from the old one again the car will idol smoothly and keep running but the BOV won't work again. We're at a loss to figure out how to fix it correctly so that all the new parts are on the car and it'll idol smoothly and not die. I'm thinking that really the only thing that is different between the two caps is the air inlet pipe that the vacum hose hooks up to.

[bcool]

There is a massive vacuum leak that was happening in the old one. You car was tuned around that leak. So now that you have the leak fixed the ecu is still adding in the extra fuel. So grab a laptop, bang out that fuel, and you'll be ready to rock.

[ScottyStyles]

There is a massive vacuum leak that was happening in the old one. You car was tuned around that leak. So now that you have the leak fixed the ecu is still adding in the extra fuel. So grab a laptop, bang out that fuel, and you'll be ready to rock.

The cap is just a metal part; everything that creates a vacuum is fresh and new, so no vacuum leaks. Greg - when you tightened that new cap down when we put it on, did you make sure every bolt was tight (kind of like I forgot to do when we put the old cap back on at first)

With the new cap: Car can't idle (just dies), and when I hold the gas down lightly to keep it from dying, the rpm's surge from 1k rpm to 2krpm, then drop back down. I'm NOT modulating the throttle at all doing that. HOWEVER, with the new cap the BOV works and I've got air coming out of it.

With the old cap: Car idles, no issues with rpm surge, and the BOV *kind of* works - small amounts of air is better than no air - but I still have mostly compressor surge.

I guess I'm just having a hard time understanding how the metal cap is creating a vacuum leak; the two are identical, absolutely no differences except for the nozzle that I put the vacuum hose onto.

[ScottyStyles]

The purple part is the "cap" I'm talking about. The replacement that I got is identical to the original that I'm replacing. I'm using all new parts except for the old cap.

http://i57.photobucket.com/albums/g213/vivaaron/AK-Car%20Parts/ak-2.jpg

[ScottyStyles]

So... after a brief discussion in the shoutbox, I unplugged the vacuum hose from the BOV, per bcool's suggestion, and the car continued to idle just fine. Where do I go next with this?

[bcool]

just tune out the fuel as needed

[Gregory]

I was going to say plug the vacum line and see what happens. But Bcool is probably right though.

[nikuman]

surge sounds cooler.