Hey all. I just finished venting the stock bov. I remove the hose from the bov to the airbox and capped the airbox with a wine cork(great fit). Now everytime I start the car it idles to 3000. It only does this after a long period of time. Like if i go somewhere and than come back 5 mintues later it will not do it. So it revs to 3000 for about 2 mintues, it will stop if i go in reverse or drive. Is this a problem with all stock vented bovs? Anyways any responses from the genuises are greatly appreciated.

 

every time you start the car when it's cold or warm/hot?

amel

 

What compelled you to disconnect the BOV from the airbox? The car should rev to 3000 when it is started cold with the stock ecu.

 

No its never started cold. I live in florida. The temp rarely drops below 75 degrees. Like in the morning tomorrow it will do it. I go to work and at the end of work it will not do it. Its like after it sits for a long time it will do it. It gets obnoxiously loud and alot of air is coming through the blowoff valve. When it revs to 3000 it stays constant at 3000 for about 2 mintues. Untill i put it in drive or reverse. As i have an automatic. Anyways I really appreciate your guys help and this site has helped me greatly.

 

The bov is disconnect from the airbox because its called venting to the atmosphere or something. Anyways it make the blow off valve very loud and I enjoy it.

 

this is called aws, blip throttle to stop it and do a search for more info on how to stop it permantly

 

This is normal. By cold start we mean like you say, it hasn't been started in a while (overnight). It's called the automatic warmup system. Mazda included it to warm up the cats before driving. It had most to do with emissions. Unfortunatly, the higher the miles go, the less positive it is to have cold apex seals revving to 3000 for an extended period. This has nothing to do with venting the BOV. I'm in Miami, and even during summer, when the car has been sitting at least about 8 hours or more, it will do this. As skunks says, you can blip the throttle as well as start the car in gear to stop this. There are more permanent ways if you search AWS.

 

stock bov leak (pull air in when not under boost)

put your hand over it.

The FD system doesn't mind too much though due the the MAP.

 

Try starting with the car in 1st gear and the clutch depressed. If it doesn't rev to 3000 then you're just seeing the Automatic Warmup working as it should...

 

Well it didnt do it at all before i vented the bov. I had it for about 3 months before and it didnt do it once. Now that i vented it, it started doing it. Alright well its fine I was just making sure it was normal and something was wrong with the engine. thanks

 

So it's perfectly safe to vent the stock BOV?

 

yes, totally safe.

 

haha n00bs..


j/p

 

A wine cork? Bad idea.

 

why is that?

 

Because as it dries, the cork will start flaking. Flaking into your airbox. Getting sucked into the engine. You get the idea.

 

Yep that would not be a good idea. Does any one know the exact dimensions of the hole i searched and found 3/4" is this correct?

 

hi you guys! new guy here to this rotary world

i've got a bone stock s4 fc t2.. manual

i tried to vent out the stock bov, plugged the hole that connects to the air housing.. and the car dies...

i really want that woooooshhh! sound... PLS Help! ^_^

i'm thinking of buying after market bov like the hks ssbov but i'm afraid that it might have the same problem

 

they only way you can do that on a FC is to use a check valve from the vac source. It's not the best way but will work for close to stock boost levels with the stock bov.

it is a MAF systems unlike the FD's MAP so it will die if it get's unmetered air. The stock bov's do let air past.

after market do not cause air leaks so they will be fine.

 

Venting the stock BOV to atmosphere will have no affect on the idle.

I have heard so many stories like; "ALL I DID WAS ...".

Then it ends up that they did something either wrong , or accidentially.

12 years FD experince including rebuiling engines.

 

dude....... RomeoFC3S talk'n about a FC. That doesn't have a MAP.