Tanman

Well, I finally got a BOV installed, but it looks like I've got the same problem a few others have had, the car will stall when idling. Watching the RPMs, it will fluctuate between 600 and 200 RPMS, then die occassionally. I have the Greddy type S on a V2 SC. I'm going to try swapping vacuum lines, but I'm hoping someone reads this and knows exactly how to fix it. I know the cause, but not everyone has this problem, so I'm curious why I'm having it?

dmontzsta

iTrader: (8)

Your BOV is most likely stuck open.

Tanman

Hehe, nice try, but that's not the problem. Others have had this problem. The issue is that the MAF detects the amount of air entering the engine and the fuel management system will supply an appropriate amount of fuel for the amount of air that's supposedly being supplied. The BOV releases excess boosted air, in effect reducing the amount of air actually supplied to the engine. The fuel is still added, but with less air, you get an air-fuel mixture that's way too rich with fuel, and this causes the engine to stall.

Some people have overcome the problem by trying different vacuum lines or by tightening the bolt on the BOV. I tried both, but neither has helped so far. Others don't have the problem at all.

Tanman

So here are the pics of the BOV. Does anyone know if I need to have a vacuum hose connected to the bottom nipple? Does anyone see anything wrong with the way it is set up right now?



I also tried connecting the vacuum hose shown here to the BOV. It is normally connected to the Hitachi boost sensor (stock part). When I did this, the BOV no longer worked correctly, I would get a loud phummm instead of a pshhhh like I normally get. This occurred with a loose and tight bolt on the BOV.

hlh0501

iTrader: (1)

i had that problem, a SAFC would probably fix it , or move you MAF past the BOV (closer to the throttle body than the BOV)..

ereet

He's right. S-AFC or redoing the piping are your options. (piping, so that MAF is after the BOV.

Tanman

I guess I'll have to get the S-AFC. On the V2 for the 5th gen, there is no way to move the MAF after the BOV without cutting the charged air pipe. The pipe between the SC and the throttle body is a solid pipe. In order to move the MAF to a position after the BOV, you'd have to cut the pipe to shorten it, then install the MAF in-line with the pipe. You V1 guys are lucky since the MAF is after the SC.

Tanman

How did you fix your problem? You didn't say for sure which way you did it .

ereet

I was under the impression 4th gen V2's also had the MAF after the BOV. I thought it was a 5th gen only thing, along with the wierd cross-tubing for the intake

hlh0501

iTrader: (1)

look at the bottom of this page

Tanman

From what I've read, getting an S-AFC won't help this problem (The New Climax). I'm considering moving the MAF, but on the 5th gen with V2, you'd have to cut the charge pipe, weld or connect square ends on both sides of the pipe (so it can attach to the MAF tube correctly). I'd also have to cut the BOV mount off and re-mount it further away from the throttle body so that the MAF section can go between the BOV and the throttle body. If you look at the pictures of my current setup, there's not enough room between the BOV and the throttle body to add the MAF tube.

All of this work will require a lot of cutting and welding, and may not be worth it just to have the BOV. Unfortunately, the Bosch recirculation valve is broken, so I'd have to buy a new one of those.

What I'm thinking is, like maxn'out said in another thread, that the BOV is not installed properly. When not boosting, the BOV should not be releasing any air, so the MAF readings should be fine. The problem I and others are having are occurring when not boosting, so there's no reason the BOV should be open, so the MAF and air/fuel ratio should be fine. I'm going to try another BOV, as well as tightening down everything on the BOV.

Tanman

From the other thread in the 5th gen forum:

Well, I checked the BOV, and it's releasing air all the time, through the main air outlet. I tried to tighten down the screw, but then the entire screw came loose:



You can tighten down this screw with an allen wrench, but on this Greddy, it won't tighten at all. I think I stripped the hole, even though I didn't do anything out of the ordinary. I just tightened the nut, then tightened the screw. Now the screw won't catch at all and can't go down at all. POS greddy cheap materials!



Right now, the BOV is turned off (disconnected the vacuum line), so it's always closed. This is ok until I get the problem solved, but I can't boost without risking damage to the blower. Of course, now I might have to get a new BOV .

Tanman

Here's the main problem now, I can't tighten down the pressure screw because the thread has been ruined:



What's weird is that the pressure screw will only go down so far, then you can see that the opening is too small for the screw to go any further. I tried to push down on the opening with a small rod, and it doesn't move. So I guess the pressure rod only goes down half an inch, and no more?



It doesn't really matter, since the pressure bolt won't stay in place because the thread has been stripped in the hole. Now what should I do?

Tanman

I got a suggestion from members of the local import car club:

Tap new grooves and use a bigger screw. As far as I can tell, the pressure release adjustment for the BOV is completely controlled by moving that screw up or down the 1/2" tall hole. Is that correct, or does the screw press down on something further inside the BOV to adjust the pressure release point?

Tanman

Bump.

DanNY

iTrader: (14)

i was always under the impression that the BOV adj is to adj how tight the spring is.

in any event..to avoid this u can always run the outlet of the BOV back to the engine or something. kinda rigging it a little. but your call.

oh your explaination of why it stalls...did u get that from kev?

Tanman

I don't see a spring on the BOV, if it's internal, you can't get to it. I think the screw on top of the BOV is all you have to adjust it.

The BOV is currently leaking because that screw is out (check my threads about how the BOV hole is stripped). It would work fine if I could get that hole re-grooved to accept a screw so I can adjust the BOV and close it off so it doesn't leak. There'd be no reason or way to reroute the air from the outlet back into the system (they cut off the flange where the stock recirculation valve feeds back to the intake pipe and welded a piece of steel over the hole).

As far as the explanation, the installers said the same thing, and it makes sense. Not sure if Kevin said it too.

DanNY

iTrader: (14)

hmm ok..prob adjust the distance the valve open then.

if you're going to tap and install the screw again..YOU BETTER make sure there's...
1. enough material for u to tap into.
2. threads are good enough to hold air since it's leaking air now.
maybe a helicoil is your better bet..but that gets messy..and i'm sure the tap/rethread method is too...your call there. maybe it's time to consider getting another BOV?

oh..just checking.

Y2KevSE

iTrader: (13)

Donald is correct.


You'll need it only if you're boosting 2 bar.


You can't use the vacuum hose going to the boost sensor. The line will never go above atmospheric pressure. Phummmm means the air was actually coming out from your filter..... which means it went PAST the blower.


You CANNOT tighten the screw after your have tightened the nut. This WILL strip and/or break the thread/screw.



As Dan said, make sure the new threads are able to hold the pressure of the internal spring. If not, you'll just strip the new threads. You would have fixed the problem by loosening the nut and bringing the screw down until you see about 8 threads left... then lock the screw in place by tightening the nut.

Tanman

What's a helicoil? Yeah, I was concerned that there's not enough material to tap. I'll have to check with the shop.

I just got this BOV new for $200!! I don't want to buy another one unless there's no other option. Sad thing is, I bought a Blitz BOV several months ago, and I'd use that, but the flange I had welded on is only for Greddy's and the Blitz won't fit on it.

Tanman

Sorry to doubt you Donald .

I guess I'll connect that lower vacuum line when I swap to a .050 pulley and make that much boost .

Ok I read the instructions afterwards and it says you have to loosen the nut, then tighen down the screw. I didn't do that, so I guess I destroyed the thread. I got worried when I saw the metal shavings and then the metal coil of thread come out with the screw.

So as far as fixing this problem, if I tap the hole and make new threads, I'd hope it could handle the same pressure as the stock threading since it's the same material. Maybe something I don't know about tapping threads though.

Concerning tightening down the screw (if done properly), the screw goes down that far? I guess 8 threads means the screw isn't that far down. If you see the pictures of my BOV, the screw can only travel about 1/2" up or down the hole. The screw doesn't go down any further than the length of the hole, does it? I mean, does it depress something further down in the hole, or is the pressure regulated only by the 1/2" movement of the screw in the hole?

Y2KevSE

iTrader: (13)

The screw is capable of going below the top of the nut. The screw depresses the object in the BOV, which in turns pushes down the spring.

Tanman

That image doesn't work but I found the site. Thanks for the information, this could save me!

DanNY

iTrader: (14)

http://www.ersco-mi.com/helicoil1.html

sorry the org server gave me the FU signal when i tried to post it.

DanNY

iTrader: (14)

so u turned the set screw before u loosen the lock nut...ouch.

if you're unsure on tapping or helicoil...best to bring it to a pro. small price to pay for your $200 BOV.

Tanman

Sigh, it costs $60 for one kit (12 re-threads). Not worth it for one use. It's a start though. Maybe someone sells something similar for less or maybe I can just use a manual tap to re-thread the hole.

DanNY

iTrader: (14)

tanman...u don't need all 12...find a shop that uses this stuff. ask them to plug one in your BOV. that's it...done deal..u go home happy.

Tanman

Looking at the pics of the BOV, the screw only goes down as far as the gold area, correct? I checked and it looks like that black hole at the bottom is too small for the screw to go through. I also tried to push down on the area at the bottom of the gold area and it wouldn't move .

Tanman

Sorry, coffee tastes like crap today so I didn't get my caffeine and I didn't get much sleep last night. It sucks laying awake in bed all night wondering how you're going to fix your latest car mod screw-up. In a few hours I would have come up with your suggestion on my own . I'll check that option out, thanks for the suggestions!

Y2KevSE

iTrader: (13)

The screw will push the gold area down. Look at your screw and see how the tip is made. That tips fits perfectly into the hole... it makes moving the gold thing easier.

The screw covers more surface area like this:
|
|
|
V


than this:
|
|
|
_

Tanman

I tried to push down on the gold part with an allen wrench and I couldn't get it to move. Maybe I wasn't pushing the right part or maybe I'm just weak . Anyways, hopefully the helicoil will fix my mistake. Thanks for the information.

[maxi-overdose]

iTrader: (3)

yo Tan....I got ur pictures but ur inbox is full. let me know when to foward the link to ya.

Tanman

I cleaned up my PMs. My rr account should be fine. I emailed you . Thanks,

20thdriven

iTrader: (2)

I get this same "PHUM" sound also between lower RPM shifts, is it destructive to the blower? If i loosen my BOV any more to release this air, the car will stall like Tanman. My SARD BOV has the same setup and tightening the spring keeps it from stalling but you deal with the PHUM sound and it doesn't sound good for the V2. Good luck with the repair.

Tanman

Well, from what Y2KevSE posted earlier, that's possibly the sound of boosted air flowing back through the intake filter? I might have read that wrong, but it means the charged air is hitting the throttle body and being forced back through the SC, then back out through the filter, which would definitely be bad. Hopefully I'm wrong or misinterpreted what he said.

Y2KevSE

iTrader: (13)

Nope, you're not wrong this time.

Tanman

Update for whoever cares:

The local shop is going to try to order the top part of the Greddy BOV (the purple part) to replace the top of mine since the threads are destroyed. I'd rather do this than try to rethread the hole, since using a thicker screw might interfere with its ability to adjust the pressure release setting on the BOV. I also suggested something like helicoil, but he said that wouldn't work because it would also interfere with the adjustment via the screw. Hopefully the top part isn't too expensive.

Tanman

First time for everything!

Tanman

As far as your problem is concerned, I guess you can try to adjust the spring to the perfect position so that you don't stall and you don't get backfeed. Or maybe just try not to accelerate hard, then stop suddenly, so the throttle plate stays open (not necessarily WOT) long enough to let all the boosted air get into the engine. Maybe try a new BOV.

Sprint

iTrader: (10)

greddy BOV are prone to leak

but that purple sure is purdy