no boost after car warms up?

[whatusername]

Ok guys been chasing this for a couple weeks now. Sice turboing the car i have not really felt the zoom zoom. Had boost leaks i been finding.last night was the first time i felt any real boost n it made me smile but this morning going to work no boost. Leaving work this afternoon i had boost again altho when it boost i see smoke from exhaust then i stop at a store and afterwards no boost sgain. Does this make sense yo anyone? I do have a cel for the 2nd o2 cuz the po plugged the pipe but i read the 2nd o2 is pretty much a dummy sensor.

 

[808MP5]

there's only a few possible causes
-bad turbo
-bad wastegate
-bad vacuum source to wastegate?
-boost leak
-exhaust leak pre-turbo

but as far as your symptoms i'm confused

 

[AzzA SP20]

only time i have seen this is with a stuck/ sticky wastegate

 

[whatusername]

How do i test the wastegate? What are tue symptoms of a bad turbo? And on i boost gauge i tead 5psi under boost and vac is -10 to -12 but i dont feel boost

 

[808MP5]

Idle vacuum is -10 to -12?
If so u have a leak somewhere

 

[whatusername]

What should my vacuum be at

 

[ap123]

18-20ish inHg idle
On deceleration mine gets to 23 inHg

 

[protege3690]

18-20ish inHg idle
On deceleration mine gets to 23 inHg

+1

mine read -10 at idle when my wastegate went bad, and when i had a shot BPV.

 

[tweety2300]

Definitely a huge vaccume leak even with intercooler piping half on lowest I've had at idle was 12-14

I'd say check bov and waste gate

 

[whatusername]

i dont think the wastegate has anything to do with i because I had the boost gauge installed before i turboed the car and it always read that low.... the problem with this boost gage is it will only read vacuum to -14 so I need to buy another gauge that goes to 30hg now the bov may b something to look at as far as my boost loss.. it could b opening under boost. it is used and i dunno how long the po used it for... its a turbo xs type h universal bov and for vacuum i may have to pull the mani and recheck the bolt from when i did the VTCS delete. mayb its leaking thru the threads?


edit. i was just reading the page on the china gauge i bought and it says the gauge reads psi from -15 to 45 psi if thats the case then my vac is in psi and not inhg so if u covert -10 psi u get psi to inHg
-10 psi
are:
-20.360206773178 inHg that would make it normal i think... but still dont explain the low boost and bucking surging like fuel cut i guess

 

[whatusername]

So i worked on the car today and found out my turbo xs type h bov eas completely siezed up.. i took it apart n found no washers inside and the piston frozen..took it apart cleaned it with a wire wheel lubed it eith grease and the piston started sliding. Put it together n saw on idle it was open added 4 random washers i found and its closed on idle but opens under boost and i start bucking... i guess i need more washers or mayb a new bov.

 

[AzzA SP20]

So i worked on the car today and found out my turbo xs type h bov eas completely siezed up.. i took it apar5 n found no washets inside and the piston frozen.. took it apart cleanedvit with a wire wheel lube it eith hrease and the piston started sliding. Put it together n dsw on idle it was open added 4 random washers i foynd and its closed on idle but opens under boost ni start bucking... i guess i need more washers or mayb a nee biv

Just remove BOV and block it off.
go for a lap around the block, if everything is normal... go buy a New BOV.

that way you can be sure that its only the BOV that is the only issue. (should be.. but you never know)

and enjoy the noise

 

[whatusername]

Ok i bypassed the bov and got boost so yea my bov is bad but when i shift i still hear the turkey like bov sound i know its back feeding thru the airfilter is that what they call compressor surge? Can the car still be driven?theres No place to get a bov right now...

 

[tweety2300]

Assuming its a normal bov pull it apart and check the oring on the very bottom, I've torn 2 of those on the eBay bovs. It's either that or the diaphragm, if its the o ring take it to autozone they can get you one

 

[AzzA SP20]

Ok i bypassed the bov and got boost so yea my bov is bad but when i shift i still hear the turkey like bov sound i know its back feeding thru the airfilter is that what they call compressor surge? Can the car still be driven?theres No place to get a bov right now...

Thats what they call compressor surge... but thats not what it is. lol
No harm in driving like that. (waiting to be flamed by US guys)

over here in Aus... we like our cars to make that noise. and drive 100K Miles on stock turbos with no issues.
only side effect is when changing gears... your AFM will me metering the same space of air more than once. meaning it richens up slightly too much, but you honestley wont even notice.

Regardless of what others will say... no harm will be done with the turbo Flutter noise.
Tried, tested and run on many cars for many years.

Just drive it until you can get another BOV.
Rebuilding may be an option if you like. I would just buy a new shiny one lol

 

[whatusername]

Assuming its a normal bov pull it apart and check the oring on the very bottom, I've torn 2 of those on the eBay bovs. It's either that or the diaphragm, if its the o ring take it to autozone they can get you one

yea i took it all apart the oring is fine the brass piston was corroded into the aluminum so i hit it with a wire wheel after i hammered the brass piece out. then i lubed it with grease but like i said it had no washers so was opening at idle. then i put in like 6 or 7 washers (different ones i found in the tool boxes) and its closed on idle but opens under boost so its still weak i think im just gonna replace it since i dont have the original washers and dont know the spring rate of the spring

 

[whatusername]

So it is okay to drive without the blow off valve even though I hear that Turkey and I don't have the stock bypass valve?

 

[MSPCHI]

It's NOT okay to drive without a BOV, the "turkey" sound you're hearing IS compressor surge and will kill your turbo, then you'll have REAL problem. Don't drive it boosting like that. It's better to have it open and have no boost, then to be boosting without a BOV. Most stock cars have bypass valves that have a quieter turkey sound. You NEED either a BOV or a BPV or your turbo will go bye bye. The "turkey" sound you hear from a bov is either one that's not set up properly or one that is.; There's a small difference in the sound between the two. One is your unused boost going the twrong way through your turbo, adn the other is it going through the pipes and out the BOV.

 

[whatusername]

Yeah I didn't think it was good to drive it like that but the other guys said yes but I think he has the bypass file I'm going to run to open until I can get a new blow off valve

 

[ap123]

Its just flutter from air in the charged pipes coming out the turbo intake of the turbo. At low levels of boost it doesn't even matter IMO, its not that bad you'll be alright it wont break the turbo. Theres plenty of people that don't run BOVs. Its not recommended but its not the horror that people say it is.

Compressor surge is different. Compressor surge does kill a turbo but that occurs under boost and under load. Thats when the compressor suddenly spikes up or down in boost and puts huge amounts of stress on the turbo. Thats real compressor surge that will kill the turbo.