Car dies when the BOV is blocked off
#1
Senior Member
Thread Starter
iTrader: (1)
Join Date: Jun 2006
Location: Outside of the Loop-ATL
Posts: 761
Total Cats: 1
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Ok so I have a new one that is completely odd.
I have a Boash BOV in a VTA setup. Car run fine like this. Then it die(read my other post). Well got the car idling fine but the bov is blowing air out(yes I said it is blowing air out) at idle. If I put my hand over the bov and seal the leak, the car dies. If I unhook the vaccum line of the BOV and seal up the new hole the car dies.
I can have the car in netural and rev the motor fine, as long as the leaking BOV is hooked up right.
WTF is going on?? I am about to pick up a known working BOV to fix that.
noted information:
stock 1.6 ECU
1.8 motor
1.6 TB
still have the shitty AFM(stock 1.6)
The car ran fine until it died on the road. The only I did to fix my other problem was removing the VC to algin the CAS easier.
Any help would be great cause I am lost.
I have a Boash BOV in a VTA setup. Car run fine like this. Then it die(read my other post). Well got the car idling fine but the bov is blowing air out(yes I said it is blowing air out) at idle. If I put my hand over the bov and seal the leak, the car dies. If I unhook the vaccum line of the BOV and seal up the new hole the car dies.
I can have the car in netural and rev the motor fine, as long as the leaking BOV is hooked up right.
WTF is going on?? I am about to pick up a known working BOV to fix that.
noted information:
stock 1.6 ECU
1.8 motor
1.6 TB
still have the shitty AFM(stock 1.6)
The car ran fine until it died on the road. The only I did to fix my other problem was removing the VC to algin the CAS easier.
Any help would be great cause I am lost.
#3
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
I'm somewhat confused. There wouldn't be any boost at idle, so you would only feel vacuum at idle through the BOV. As posted, I would check your idle setting, but this is what would be happening to your car right now: Your AFM box will be metering the amount of air it sees, and since air is also coming in at your blow off valve, your car would be running leaner then it should (more air then fuel). By blocking off that BOV, your car should see the proper air/fuel mixture, and should run better.
#4
Senior Member
Thread Starter
iTrader: (1)
Join Date: Jun 2006
Location: Outside of the Loop-ATL
Posts: 761
Total Cats: 1
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
I'm somewhat confused. There wouldn't be any boost at idle, so you would only feel vacuum at idle through the BOV. As posted, I would check your idle setting, but this is what would be happening to your car right now: Your AFM box will be metering the amount of air it sees, and since air is also coming in at your blow off valve, your car would be running leaner then it should (more air then fuel). By blocking off that BOV, your car should see the proper air/fuel mixture, and should run better.
I also tried adjusting the Idle air valve screw like you said Brain. If I open the valve all the way and then cover/removed vaccum of the BOV the car barely ran and ran like ****. Popping often and idling like ****.
i am 100% at a lose here
#6
Senior Member
Thread Starter
iTrader: (1)
Join Date: Jun 2006
Location: Outside of the Loop-ATL
Posts: 761
Total Cats: 1
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
I have change nothing. The car was running good before the CAS. It was running a little rough, kind more of an high idle and running rich but once load was applied to the motor the car smoothed out. Now if I try to add load to the motor the car just bogs down.
#8
Senior Member
Thread Starter
iTrader: (1)
Join Date: Jun 2006
Location: Outside of the Loop-ATL
Posts: 761
Total Cats: 1
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Also if I push the flap door open without adjusting the TB and car started to die.
This made Eric and I both think that it kinda of sign as the AFM is still working.
#9
Moderator
![](/mt2011/images_td/ranks/supporter1.gif)
![](/mt2011/images_td/ranks/moderator.png)
iTrader: (12)
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 20,884
Total Cats: 3,075
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
I didn't think the stock ECU would let the car run right if you were VTA anyway.
Did you try routing the blowoff back into the intake tract behind the afm so that at least all of the air gets metered?
Did you try routing the blowoff back into the intake tract behind the afm so that at least all of the air gets metered?
#10
Senior Member
Thread Starter
iTrader: (1)
Join Date: Jun 2006
Location: Outside of the Loop-ATL
Posts: 761
Total Cats: 1
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Well... I know the stock ECUs don't like VTA... the weird thing is that the car has been running for about a month now in VTA with out any major issues. Granted until now the BOV didn't leak at idle. I have a Greddy RS next to me that should seal at idle. I need a bigger hose so I can try it.
#12
Senior Member
Thread Starter
iTrader: (1)
Join Date: Jun 2006
Location: Outside of the Loop-ATL
Posts: 761
Total Cats: 1
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
ok yea I know VTA with an AFM is not the correct way and has it issues... but 1) the car been like that for over a month no real issues.
2) even if I remove the BOV signal, closing the BOV the car dies so the BOV being VTA doesn't explain why when it's not leaking the car dies..
Explain why the big "hole" in my intake system is an out instead of a nomal in and why when that "hole" is sealed the car instanely dies.
#14
Senior Member
Thread Starter
iTrader: (1)
Join Date: Jun 2006
Location: Outside of the Loop-ATL
Posts: 761
Total Cats: 1
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
I have a single line running from the IM to the BOV. Also a single source from IM to Boost Gauge. My FMU and FPR is source together of the back of the manifold. Everything is hooked up, and just like it was before the car dieing.
I have double check to make sure I didn't change since before my CAS backing out.
#16
Boost Czar
![](/mt2011/images_td/ranks/supporter1.gif)
![](/mt2011/images_td/ranks/admin.png)
iTrader: (62)
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,688
Total Cats: 4,113
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
if the car is running and you unplug the AFM it should still idle, since the vacuum is pulling the flapper open, the fuel pump stays grounded. You should also be able to start the car with the AFM unplugged, but you cannot rev the motor.