Ok boys I need some help. It seems like my BOV is opening more than it should at idle and is causing a lean misfire at idle/development.

According to the Magic internet box BOV's should open under idle vaccume. Appariently on stock healthy blocks our VQ's run around 20-21psi of vaccume.

Well at idle when the BOV opens I get a super rough idle. My tuner even told me my BOV was causing a lean out in idle and he had to up the idle rpm to combat it.

i just opened my tial 50 and have either the brown or plain spring, according to the chart I either have the -21in/hg to -23in/hg (12 psi) spring which is brown. Or I have the plain spring which is the -18in/hg to -20in/hg. (11psi)

But it's still opening to a decent amount at idle and pretty sure it's the cause of my lean out misfire my engine keeps throwing. And the reason at times if I clutch in at 3-5k rpm the engine rpm tanks and engine dies.

 

My question is the vaccume hose inlet at the top of the Tial 50. It has a hole that I have picked up with the top screw to allow the vac pressure into the BOV. Is that meant to be turned and block off part of the access port into the BOV to limit/lower the veccume intake on the BOV to not pull it open on idle/decel?

 

It's a bango style fitting it doesn't matter although lining it up is always best

Are you turbo charged or supercharged?.I have the Tial 50mm set up for my procharger kit. I have the 3 in/ vacuum spring.My BOV is wide open at idle.

 

As far as I know it's the turbo. It's a stiff spring. According to the paperwork super charger is green or pink with the old BOV's. Brown yellow and other colors are for the turbo version.

As you see mine is plain or brown.

And yea I found that out. I spun it to nof line up and it made no difference.

 

I don't see how your BOV opeing up is leaning you out? With the BOV open your not getting as much air in the intake tract so you should be going rich, unless your computer is sensing the loss in air and is trying to compensate and dcking it up. I dont know if this helps but here is a Tial guide on BOV's and Springs.

 

Yea I have that chart. But my idle only changes to lean when the BOV opens either at idle or when I let of throttle.

 

When you left of the throttle makes sense, since your killing your fuel and its only air going through the motor.

Are you MAF of MAP tuned?

Did this just start happening?

Do you have the stiffest spring available?

If you take the Vacuum line off of BOV does it still open at idle or only when you have vacuum applied?

Is the Diaphragm cut in your BOV?

 

Is your BOV before or after the MAF sensor

 

Before. But i think being so big it can't make up for it at such a rapid rate when I come off the throttle in higher RPM's.

Been happening since I introduced the turbo kit.

As far as I know yes. You can see it pictured and you see the chart.

Nope as soon as you pull the hose it slams shut.

Nope still in tact.

 

If the BOV is before the MAF then the air should be accounted for. Otherwise change the spring or add washers to increase springrate. I use a cheap $40 RFL and I do not have this problem.

 

Yea that's why I'm asking. I'm literally out of logical reasons why this is happening.

But it's from the BOV. Cause it only happens when it opens.