JimBot

How's it going peoples! It's been years since I've been on this forum and also been years since I've owned an RX7.... after switching through 7 other cars in the past 5 years .... I'm back to a 1990 Turbo 2 LOL

Anyways, I recently purchased a used Sheepdog Prof BOV that comes attached with the piping to drop into the stock TMIC setup. I thought the installation was pretty straight forward, but when I i turned the car on after the install it immediately stalled as if there was a huge vacuum leak. The car ran perfect on the stock BOV. I connected all the lines and vacuum lines and capped the hole to the TID. Doesn't seem to be any signs of leaks.
My only uncertain area is the vacuum line that comes off from the stock BOV. I'm supposed to hook that up to the nipple on the aftermarket BOV right? (my old t2 came with an aftermarket bov already so I'm not 100% sure on this)

Any feedback or advice will be great!

Thanks!

texFCturboII

iTrader: (17)

Yes, you need a vacuum line to the BOV.

JimBot

yeah, did that .... car still stalls

any ideas?

texFCturboII

iTrader: (17)

Is the BOV stuck open?

Bamato

iTrader: (6)

^^This would be my first guess.

N1XRR

Try covering the open part of the BOV and starting the car up. It really sounds like your BOV is stuck slightly open.

boosted1205

iTrader: (9)

Did you buy a knock off BOV ? Although it says "GENUINE" a lot of times it's not. If you got a new unit cheap, most likely it's a knock off.
You have a huge vacuum leak at the BOV. Remove the BOV and see if the bottom is sealed. When you push on the valve, it should be very stiff.

JimBot

i'm almost positive that its authentic. Material is very good quality and it has "Prof" engraved on the back which the authentic sheepdog prof bov's have.
By being stuck open do you guys mean that its defective or is the adjustment screw super loose?

driften16

iTrader: (1)

try adjusting it a lil tighter if the bov isnt stuck open ....is there a gasket under the bov?

pacman74

Do you have the BOV recirculating into the TID? If you have the BOV venting to open atmosphere, it will stall. This is because FC's use a Mass Air Flow sensor as opposed to a MAP (Manifold Absolute Pressure) sensor like FD's. You need to either recirculate your BOV, get an "anti-stall" kit, or get a Power FC and swap to a MAP sensor.

10yearrx7

iTrader: (2)

My type rs worked fine venting to the atmosphere

pacman74

Read the last paragraph of page 6: http://www.greddy.com/upload/file/11541101_bi.pdf

texFCturboII

iTrader: (17)

This MAY happen when DRIVING. The OP is saying that he cant even get it to run. I have ran BOVs that vent to the atmopshere with absolutely no issues, never stalling once.

A Blow off valve is just that, a valve. If the valve were stuck open, then you would have a huge vacuum leak because there would be a giant hole in the system where the air would typically escape under pressure. This is what we are saying we suspect it is. Remove the BOV and inspect to see that it opens and closes properly.

pacman74

This has actually been discussed many times before, I'll just explain what's happening. Since FC's have an AFM (which is in front of the BOV), the AFM is telling the ECU that more air is coming into the system than there really is (in other words, the voltage from that sensor is not going to be accurate). This is because at idle, the engine is experiencing vacuum which has a direct affect on the BOV that causes it to open. Since the BOV is open, it is loosing air. The result of this is that the amount of air that the engine was expecting to get, relative to fuel, is inaccurate.
If you can crank down the adjustment bolt on the BOV enough so that it is completely closed at idle, then you should be OK. Although, I'd suspect that if you did this, you would get some flutter from your turbo when you get off of boost.

Here's a quick test, make sure you don't have any other intake leaks and then cover the opening of the BOV with your hand. It should idle fine at that point.

texFCturboII

iTrader: (17)

Huh? I don't get it. Are you saying that it is normal to have an open BOV at idle?

pacman74

It all depends on the BOV and the way it was adjusted to begin with, but yes, most BOV's (the way they come from the factory) will be slightly open during idle. This is because the primary purpose of a BOV is to prevent turbo surge when you let off the throttle and the way to do this most effectively is to have your BOV configured as sensitive as possible. So, to prevent this from happening, you can crank down on the adjustment screw on the BOV just to the point where it is closed during idle, no more than that. But like I said earlier, that will make the BOV less sensitive and more prone to turbo surge.
This is not a problem in cars that have MAP sensors because MAP sensors get their readings directly from the intake manifold, which lies after the BOV.