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Boost from bov vaccum line

2ggst1998

Proven Member
88
1
Jan 19, 2015
torrance, California
Is there suppose to be any boost coming fromthe bov vaccum line? Is this a bad bov? The vaccum line pops off under wot
 

2ggst1998

Proven Member
88
1
Jan 19, 2015
torrance, California
Where would u suggest i attach the tester, i hooked it up to the the throttle body and lower intercooler piping. Should i attach it to the turbo inlet? And wouldnt 40 psi damage something?
 

2ggst1998

Proven Member
88
1
Jan 19, 2015
torrance, California
Also the boost gauge sits like 2cm too high at idle, it doesnt rest at the bottom if the gauge in the car, idk if this anything
 

97_4g63t

Supporting VIP
472
49
Jun 6, 2010
carlsbad, New_Mexico
Where would u suggest i attach the tester, i hooked it up to the the throttle body and lower intercooler piping. Should i attach it to the turbo inlet? And wouldnt 40 psi damage something?
you don't have to test that high. I'm running over 30 psi so that's why I test that high. I would just test to like 15 or 20 if I was you. The stock boost gauge is useless.
Attaching it to the turbo tests everything. That's where I test. What kind of tester are you using? You Really need a wide band and aftermarket boost gauge.
 

2ggst1998

Proven Member
88
1
Jan 19, 2015
torrance, California
Im using a diy tester, it works good. But i dont believe i should need any of that for a car that has such limited mods like mine. I believe it should be easy to find i just needa keep digging
 

2ggst1998

Proven Member
88
1
Jan 19, 2015
torrance, California
Im using a diy tester, it works good. But i dont believe i should need any of that for a car that has such limited mods like mine. I believe it should be easy to find i just needa keep digging
 

rough

Proven Member
802
73
Nov 12, 2012
Indianapolis, Indiana
Ok but how do some 2g dsm drive totally fine with no modifications when they swap a 14b

Could be something wrong with the WGA sticking, could be a modified ecu..

Could be a failing fuel pump or clogged fuel filter. Injectors could be clogged.

Just because one person slams a 14b on and has no problems, doesn't mean you will have the same results as they had! :)
 

2ggst1998

Proven Member
88
1
Jan 19, 2015
torrance, California
But this car has had this problem even with the t25 which leads me to believe its something else, also my car has just been serviced so, new fuel filter, timing belt, ive swapped identical injectors with still no luck. Checked for boost leaks and had two, i sealed those up. Maybe i should start to downgrade my car until its completely stock. Like removing the ic piping, bov and intake
 

1QUICKDSM

Proven Member
32
1
Feb 22, 2015
Raleigh, North_Carolina
You should definitely address your CEL issues and go ahead and perform a BLT while your at it. Also look into maybe getting new plugs and wires.
 

rough

Proven Member
802
73
Nov 12, 2012
Indianapolis, Indiana
Life is grand, I'm having similar issues now that has randomly appeared. I myself will be running a BLT tonight, as I just installed new UICP and BOV thinking the OEM plastic pipe was the problem, well it was partly the problem, Wouldn't hold pressure at 19psi. Now I can make it to about 6k before it cuts. I will be BLT'n for 30 psi.

Only thing that I changed since this happened was a wally 255 and 660'cc injectors "i'm not sure they really are 660cc from how low I had to scale them" Even after these two were installed I had no problems, just happened one day when I floored it and hit what seemed to be fuel cut, I looked at the wideband and she was in the 9 range.

I thought maybe it could be my tune so I put a stock rom back on, car runs the same as my tune, which is another reason I believe the injectors I was sold are so not 660cc!
 

enriquez2000

Proven Member
1,698
209
Oct 5, 2014
fort collins, Colorado
I always use new seals :) I need to do the BLT, I crashed out the other night, just need to stop being lazy!
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Hmmmm those seals failed on me immedieatly with those style injectors... may want to check. Those should require an fic seal kit
 

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Mike_GST

Proven Member
89
8
Jan 5, 2016
Brazil, South_America
I think a lot of people are confused on how bov's and wastegates work. The bypass valve is normally closed due the the spring pressure this holds the bov shut but not well enough the reason for the vacuum/boost line it 2 fold. Under boost above spring pressure boost fills on top of the diaphragm helping the spring. When the throttle plate closes between shifts boost turns to vacuum the line then vacuums above the diaphragm and over comes spring pressure opening the valve. This is the only real reason for the spring waste gates work in the same way. Just reversed vacuum helps the close and boost opens mbc bleed off set psi to reach higher boost psi than the spring can handle. But if exhaust pressure surpasses spring pressure the flap will creep open no black magic just good old mechanic theory most important thing when coming to turbo cars vacuum lines run both ways vacuum under vacuum and boost under boost. N/a cars only run vacuum. I think this is a concept some people over look when moving from 1 car line to another and y boost leaks cause so much problems so some leaks will hold vacuum because it's suckling the seals in. And there may be something there that helps the sealing like a lip or boss around the injectors. But under boost these seals get pushed out with nothing to hold them in place remember the KISS method. Don't over think things and. Keep It Simple Stupid.

Oh man! That made universe making sense again!
I rejected two BOVs because of leaks through the recirculating hose.
Now I see, probably the BOVs were fine, my leak test is the one that's missing something.
I was applying pressure on the boost line with the vacuum line disconnected.
This way, the BOVs holded just 2psi. Coincidence? NOOOO.
2psi is the boost the BOVs can handle just on the spring force.
After that, it needs help from the vacuum line (supplying boost) to keep the piston down sealing the bypass.
I can't wait to test for leaks again with the vacuum line pressurized too.

I'm almost sure my stock BOV is bad. The spring must be ok, but the diaphragm not.
That could explain why my car runs ok on low boost (just on spring), gets all shaky on middle boost and can't reach high boost (leaking boost through the diaphragm).

THANK YOU!
 
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