BOV opens without releasing throttle

[PDX-GST]

I have been working on fixing multiple boost leaks over the last few weeks and have fixed all but one small leak at the weld on the bov flange. It hold pressure pretty well now so I thought my stuttering issues would be gone.

They remain, and even sometimes with the throttle wide open it will start to stutter then the blow off valve will quickly open for a second at about 12psi then keep stuttering.

If this isn't a boost leak issue anymore what could be causing the blow off valve release without letting off the throttle.

Could it be an issue with vacuum? What exactly initiates the release of the blow off valve?

 

[bryanwheat]

Are you sure that the bov is actually opening and you aren't just experiencing a misfire?

 

[WES_393]

Could it be an issue with vacuum? What exactly initiates the release of the blow off valve?

What initiates the release of the BOV is pressure difference. At WOT there is equal pressure (boost) in the intake pipes and the BOV itself. This keeps the BOV shut since there is no pressure difference to force it open. Once you close the throttle plate (let your foot off the gas) there will be pressure in the intake pipe, but vacuum in the intake manifold and all the things that connect to it (like the BOV). Since there is now zero pressure in the BOV, the pressure from the intake pipes will push the valve open. Vacuum from the intake manifold helps keep the valve open, but once the pressure in the intake pipe drops to nearly zero, the spring in the BOV will push the BOV shut as to prevent a vacuum leak.

So with that said, if your using the stock 2g BOV, it is pretty well known for leaking under anything higher than stock boost and I would suggest replacing it. But either way, perform another boost leaks test and make sure the BOV isn't opening or leaking at all while the intake is pressurized. Also inspect the hose that runs from the intake manifold to the BOV for cracks and tight fitment to make sure the diaphragm of the BOV isn't losing pressure while the intake is pressurized. This could cause a pressure difference which, like explained, is what allows the BOV to open.

 

[PDX-GST]

Are you sure that the bov is actually opening and you aren't just experiencing a misfire?

This is def not it. The pressure on my gauge drops when this happens and it is for sure the sound of the bov opening.

So with that said, if your using the stock 2g BOV, it is pretty well known for leaking under anything higher than stock boost and I would suggest replacing it. But either way, perform another boost leaks test and make sure the BOV isn't opening or leaking at all while the intake is pressurized. Also inspect the hose that runs from the intake manifold to the BOV for cracks and tight fitment to make sure the diaphragm of the BOV isn't losing pressure while the intake is pressurized. This could cause a pressure difference which, like explained, is what allows the BOV to open.

Actually I just replaced the bov with a greddy type rs and ran a boost leak test 5 minutes before driving it. Ran the pressure up to 15psi and and the needle on the gauge of my boost leak tester slowly went down. I still have a very small pin hole leak on my flange where the weld is to the pipe, but shouldn't effect anything this much. I also recently replaced most of my vacuum lines including the hose from the intake manifold to the bov and the hose from the tb to the fps and the hose from the fps to the fpr.

The other thing that I should mention in that no mods have really been made on this car in the way of boost pressure. I don't plan to do anything until I have everything up to par. This seems to happen I reach about 12-13 pounds of pressure. What is stock boost supposed to be?

 

[WES_393]

Stock boost for a 2g is about 10psi. Try adjusting the BOV to a harder setting. It seems it's opening way to easily. For the boost leak test I would suggest running it at 20psi. Also use a spray bottle of soapy water to find boost leaks. If there is a leak, it will start to make bubbles once sprayed.

 

[bryanwheat]

Did this just start happening with the new bov?

 

[PDX-GST]

Stock boost for a 2g is about 10psi. Try adjusting the BOV to a harder setting. It seems it's opening way to easily. For the boost leak test I would suggest running it at 20psi. Also use a spray bottle of soapy water to find boost leaks. If there is a leak, it will start to make bubbles once sprayed.

I have done many boost leak tests using this method. I know I am down to just one small leak. Very small leak. So far I have repaired the following leaks.

Fuel Injector seals
Throttle body Shaft Seals
Biss Screw And O ring
Replaced all the factory IC Pipes with Hard Pipes
Replaced Factory BOV that was leaking bad

I have beat the boost leak test and hunt to death.

Did this just start happening with the new bov?

I had these stuttering issues long before, this is when I started hunting down all my boost leaks.

I don't think I ever had the bov open up though until just recently without letting off the throttle. The bov holds strong. I tested it on the upper ic pipe alone before I put it on the car. I hooked up my boost leak tester to one end of the pipe and plugged off the other end and the bov did not leak at all.

 

[mchustle]

Do you have anything t'd into your bov vac line?

 

[niddydsm]

all boost leaks are fixed and the bov was replaced. I would start looking at Fuel filter and pressure.

 

[PDX-GST]

all boost leaks are fixed and the bov was replaced. I would start looking at Fuel filter and pressure.

Ok, I will take a looks at that. Possible the injectors too? I should also say that once the car is completely warmed up, this does not seem to happen.

 

[niddydsm]

sounds like fuel system

 

[PDX-GST]

Well I kind of feel like an idiot, but I will post anyways for the sake of resolving this thread and possibly helping someone in the future.

All my issues were resolved by changing out my spark plugs. They were pretty bad. Car runs like a champ now. Thanks for all the help guys. Now that I am running strong, sounds like its time for a new upgrade. I think exhaust is next.

 

[bryanwheat]

Well I kind of feel like an idiot, but I will post anyways for the sake of resolving this thread and possibly helping someone in the future.

All my issues were resolved by changing out my spark plugs. They were pretty bad. Car runs like a champ now. Thanks for all the help guys. Now that I am running strong, sounds like its time for a new upgrade. I think exhaust is next.

So it was a misfire.

 

[Bud92gsx]

I think you should replace the crappy 2g bov with a 1g and call it a day.That should be the next mod, 30 bux shipped, that still leaves room for ebay exhaust.

 

[PDX-GST]

So it was a misfire.

Yes I guess it was. Sorry I have never experienced a misfire and it sounded like my bov opening. Unless the misfire caused vacuum to open the bov. But regardless thanks.

I think you should replace the crappy 2g bov with a 1g and call it a day.That should be the next mod, 30 bux shipped, that still leaves room for ebay exhaust.

I have a brand new Greddy Type RS that replaced my crappy 2g bov already, but thanks for the recommendation. Got rid of it when I was chasing boost leak after boost leak for a couple weeks.

 

[Fast-Orange]

Spark plugs and the stock wires are notorious for causing this problem. Change your wires with your plugs. If you had any carbon tracking on your old plugs and you swap in new plugs they will quickly fail due to your wires change them both.

 

[PDX-GST]

Spark plugs and the stock wires are notorious for causing this problem. Change your wires with your plugs. If you had any carbon tracking on your old plugs and you swap in new plugs they will quickly fail due to your wires change them both.

Thanks, I will do that. Was actually going to buy some today, but they were out of the NGK wires. Tried to buy some magnecore wires off someone in the classifieds section of this forum and someone beat me to them.

 

[Artago]

Update your profile... like yesterday...

 

[Bud92gsx]

Update your profile... like yesterday,cause yesterday there were no mods...

Fixed.+2

 

[PDX-GST]

Update your profile... like yesterday...

Funny cause I did update my profile with the small amount of mods I have done right after the last post I made last night. Thanks for the polite suggestion.

Fixed.+2

I marked this post resolved yesturday.

 

[Bud92gsx]

Noobs being dicks.Have fun with that.

I'll just not try to help you anymore.

Close this up, because obviously this guy has this all under control.

 

[PDX-GST]

Noobs being dicks.Have fun with that.

I'll just not try to help you anymore.

Close this up, because obviously this guy has this all under control.

Yo dude, back up. Obviously I am not the one being a dick here. I appreciate all the help I can get, this is why I am here and everybody has been very helpful. You are the first to pop off to me here.

I admitted my mistake to bryanwheat and that he was right, and thanked him for his input.

I make no claims to be an expert here by no means, I am learning from the best on here and comments like the one I just got from you don't help at all. So as you said that you don't need to help me anymore, I am good with that. Input from people than can respect others especially newbie's is much appreciated though. Much like the help I got from everybody else.

 

[Bud92gsx]

At least you can admit it.I've seen a few know all noobs.

So then I apologize for my dickish bevavior, and retract not trying to help you out anymore.

No harm no foul

 

[PDX-GST]

At least you can admit it.I've seen a few know all noobs.

So then I apologize for my dickish bevavior, and retract not trying to help you out anymore.

No harm no foul

Alright man, thanks. I appreciate it. I will once again accept your help and glad we could resolve this short dispute so quickly.