blow-off problem

Life is Supra · 12-22-2011, 02:01 PM

Hi guys,I have a problem whit greedy blow-off type s.You will see on picture how I redirected him and where do I go wrong whit vacuum lines because he dosent work and I hear very little air comes out and if somewone can help me please

cre · 12-22-2011, 10:58 PM

That BOV appears to have an outlet which is intended for recirculation... It's not built with making a lot of sound in mind. Fill you mouth with air like you're going to whistle or blow up a balloon and then suddenly, open your mouth all the way... it's a lot more effective at getting rid of the pressure but is a lot quieter than whistling until the air is gone.

It also appears that the BOV has an adjustable cracking pressure; You adjust the nut to determine at what level of vacuum it opens the valve. This is used to keep the valve open under low boost conditions where surge isn't as big of a concern in order to improve response between shifts. Basically, the higher it's set for the higher the amount of boost needs to be before the shift for it to open. If it opens too early the valve may remain open while at idle or really ruin your performance during casual driving... both are bad but the valve remaining open is VERY bad if there's no filter on it. Refer to the manual for information on adjusting the cracking pressure or just experiment with it.

Life is Supra · 12-23-2011, 03:07 AM

Yes I know what blow-off stands for,and yes I adjust nut for pressure but it isnt working at all....and thats why I need somewone to tell me of that vacuum lines.by the way thanks alot.

cre · 12-23-2011, 05:54 AM

I think you misunderstand. I wasn't questioning if you knew what blow off means. I was pointing out that a recirc fitting on a BOV isn't going to sound the same or as loud as a horn on the same BOV.... same device completely different sound and exhaust rate. I was trying to make sure you knew that you cannot judge whether it's working or not merely based on sound.

There is no way for anyone to know if it's routed correctly from just that one picture. The reference/trigger needs to be plumbed to a vacuum port which is after the throttle body for proper operation. If it doesn't open then the problem lies elsewhere.

cre · 12-23-2011, 05:59 AM

By the way, I also believe the lower port on that BOV needs to be connected to a boost reference (A vacuum port BEFORE the throttle body.).

Life is Supra · 12-27-2011, 12:36 AM

I try the way u sad and its working very well.

Steel its not that noisy but it shouldnt be because my boost pressure is stock(0.6bar)

Life is Supra · 01-03-2012, 01:24 AM

Hi again,like I said the BOV vent and works good but now I have a problem with large rpms in neutral(1500-1600).Please help me i dont know what to do

cre · 01-03-2012, 04:37 AM

Check for vacuum leaks, test the air flow meter and if the BOV is still venting to atmosphere check to see if it's staying open while the system is in vacuum (not boosting). Check for any stored diagnostic codes too (see the MKIII FAQ section for info on how if you don't know already).

Life is Supra · 01-03-2012, 01:55 PM

I think its bov stays open a bit when theres no boost.A nd I sound stupid to u,but what shoud I do now?Where to look and does the bov have a issue and because of that stays open or I have to close it a little?I didnt check codes,but last time I check it there was just one-I think 52 for a/c that is on.

cre · 01-04-2012, 04:32 AM

Code 52 is a knock sensor circuit malfunction and will cause severe operational problems. Code 51 indicates that either the A/C is in operation or the IDL switch in the TPS is open and is not a critical code although you should make sure that the error was indeed because the A/C was on or the throttle was open.

FYI - you can not set the timing with any codes present.

If the BOV is remaining open then you either have the spring too loose, the vacuum lines are not properly routed or the BOV is damaged. With a recirculating setup it isn't an issue at all as long as it's closed when boosting... one more win for recirculating.

12-22-2011, 02:01 PM	#1
Life is Supra 3" Exhaust Join Date: Apr 2010 Location: Serbia Posts: 51	blow-off problem Hi guys,I have a problem whit greedy blow-off type s.You will see on picture how I redirected him and where do I go wrong whit vacuum lines because he dosent work and I hear very little air comes out and if somewone can help me please Attached Thumbnails

12-22-2011, 10:58 PM	#2
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	That BOV appears to have an outlet which is intended for recirculation... It's not built with making a lot of sound in mind. Fill you mouth with air like you're going to whistle or blow up a balloon and then suddenly, open your mouth all the way... it's a lot more effective at getting rid of the pressure but is a lot quieter than whistling until the air is gone. It also appears that the BOV has an adjustable cracking pressure; You adjust the nut to determine at what level of vacuum it opens the valve. This is used to keep the valve open under low boost conditions where surge isn't as big of a concern in order to improve response between shifts. Basically, the higher it's set for the higher the amount of boost needs to be before the shift for it to open. If it opens too early the valve may remain open while at idle or really ruin your performance during casual driving... both are bad but the valve remaining open is VERY bad if there's no filter on it. Refer to the manual for information on adjusting the cracking pressure or just experiment with it. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

12-23-2011, 03:07 AM	#3
Life is Supra 3" Exhaust Join Date: Apr 2010 Location: Serbia Posts: 51	blow-off problem Yes I know what blow-off stands for,and yes I adjust nut for pressure but it isnt working at all....and thats why I need somewone to tell me of that vacuum lines.by the way thanks alot.

12-23-2011, 05:54 AM	#4
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	I think you misunderstand. I wasn't questioning if you knew what blow off means. I was pointing out that a recirc fitting on a BOV isn't going to sound the same or as loud as a horn on the same BOV.... same device completely different sound and exhaust rate. I was trying to make sure you knew that you cannot judge whether it's working or not merely based on sound. There is no way for anyone to know if it's routed correctly from just that one picture. The reference/trigger needs to be plumbed to a vacuum port which is after the throttle body for proper operation. If it doesn't open then the problem lies elsewhere. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

12-23-2011, 05:59 AM	#5
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	By the way, I also believe the lower port on that BOV needs to be connected to a boost reference (A vacuum port BEFORE the throttle body.). __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

12-27-2011, 12:36 AM	#6
Life is Supra 3" Exhaust Join Date: Apr 2010 Location: Serbia Posts: 51	I try the way u sad and its working very well.Steel its not that noisy but it shouldnt be because my boost pressure is stock(0.6bar)

01-03-2012, 01:24 AM	#7
Life is Supra 3" Exhaust Join Date: Apr 2010 Location: Serbia Posts: 51	Hi again,like I said the BOV vent and works good but now I have a problem with large rpms in neutral(1500-1600).Please help me i dont know what to do

01-03-2012, 04:37 AM	#8
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Check for vacuum leaks, test the air flow meter and if the BOV is still venting to atmosphere check to see if it's staying open while the system is in vacuum (not boosting). Check for any stored diagnostic codes too (see the MKIII FAQ section for info on how if you don't know already). __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

01-03-2012, 01:55 PM	#9
Life is Supra 3" Exhaust Join Date: Apr 2010 Location: Serbia Posts: 51	I think its bov stays open a bit when theres no boost.A nd I sound stupid to u,but what shoud I do now?Where to look and does the bov have a issue and because of that stays open or I have to close it a little?I didnt check codes,but last time I check it there was just one-I think 52 for a/c that is on.

01-04-2012, 04:32 AM	#10
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Code 52 is a knock sensor circuit malfunction and will cause severe operational problems. Code 51 indicates that either the A/C is in operation or the IDL switch in the TPS is open and is not a critical code although you should make sure that the error was indeed because the A/C was on or the throttle was open. FYI - you can not set the timing with any codes present. If the BOV is remaining open then you either have the spring too loose, the vacuum lines are not properly routed or the BOV is damaged. With a recirculating setup it isn't an issue at all as long as it's closed when boosting... one more win for recirculating. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

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