Hey guys my car failed smog on the EVAP portion of the test and I noticed that both of the hard lines going to the canister had holes on them cause of a rat so I went to the parts store and got vacuum hoses that fits snug over the existing hard lines and so I cut off the portions which had holes and used the vacuum hoses i got to connect the lines back, but now my car feels like a slug I checked all the vacuum lines, tightened up all the clamps and even did a starter fluid test but no luck, the boost gauge used to go 3/4 to the white bar and now it doesn't even go half way, no check engine light either

 

I'd guess at a crossed vacuum line. It's pretty strange to fix something and have poorer performance.

I wouldn't worry or rely on the colors if your hoses still have them but follow each vacuum line from one point to the other.

Did it set a check engine light before ? Does it have a light on now ?

 

it had a check engine light for "shift soleniod B" and "system running rich bank 1" when I got the car a month ago. I replaced the PNP switch cause it was bad then I cleared the codes right after and the check engine light hasn't turned on since then and I did the job within the first week of owning the car... I did another starter fluid test just to make sure I didn't miss any spot and sprayed every vacuum line I saw and I've almost emptied out the can but still no luck, I even removed the vacuum hose that goes to the CBV to see if the CBV is broken but the car still ran on low boost, I remember the blue hose on the diagram being disconnected after owning the car for 3 days but even so the car was boost happy even after i reconnected it, this really puzzles me.. it happened almost instantaneously after fixing the EVAP hoses...

 

Bump. Anyone have any ideas what the problem could be? I miss my car hauling a** its really no fun now

 

Bump, anyone?

 

A bad turbo control valve can cause low boost problems. unplug one of the vacuum hose leading to the turbo control valve and see if the boost gets back.
http://www.matthewsvolvosite.com/for...hp?f=1&t=32575

 

l am having low boost problems too. change the TCV and yet still low boost. before my changing my tcv, the needle hardly moved on the white side, after changing the tcv my boost is not as bad as it was. it goes 3/4 of the white side.l am looking forward to turning my wastegate two turns in when it gets a little bit warmer outside. if it doesnt help l will have to uninstall the turbo and see whats going on in there.

 

alright I did what you told me and yes my boost is back, I'm going to change it today and I'll report back when I get a new one installed

 

that's where usually where my gauge goes before I had the low boost issue (3/4 to the white side)

 

do not boost your turbo with the vacuum hose unhooked. you will hit fuel cut off and probably destroy your turbo. same happened to me. am still getting low boost with one hose unhooked. hook the lines back on till you change your tcv. Good luck buddy. also make sure you get the lines back the same way out. dont mix the lines or else your boost will be lost again.. l would recommend IPD hd tcv. its better and cheaper.

IPD Heavy Duty Turbo Control Valve (HD TCV) - 850 S70 V70 C70

 

yeah I figured so I just drove around with it unhooked but didn't let it hit fuel cut or get the needle to go all the way, I just let it hit the 3/4 mark and let go of the throttle lol, thanks I will try the Ac Delco mod that some people are doing, I heard that it was better and only costs around 30-40 bucks Ac Delco Boost Control Solenoid / Tcv Mod Impressions - Performance Modifications - Volvospeed Forums I will report back when I replace the part

 

hey man! I still havent replaced the part yet but my boost went back! so today as i was sitting in the L.A. traffic and my check engine light went on and my car threw the P0442 code and which means "EVAP Small leak" I dont know what triggered it but it could be from not tightening up my gas cap properly earlier today so when I got home i plugged in my OBD scanner and cleared the code then I went for a test drive and alas! my car boosted like it did before and no check engine light so far. (I really hope it doesn't come back lol) but yeah that's how I resolved my issue, in a very odd way... lol.

 

Good, l have been getting that code too. but my boost remains the same. is the boost back on with all the vacuum hose connected?

 

yes i left all the vacuum hose connected, today my dad took the car to work and when he got home i took the car for a test drive and noticed that the ECU pulled the boost back yet again then I plugged in my scanner and it pulled no codes but I still used the erase feature and my boost was back again, now I'm totally confused i replaced my gas cap with a spare gas cap we have laying around the garage and will see if that's the cause of this funny business...

 

And I'll also leave the battery unplugged overnight and see if that will also stop it from being greedy and not giving me any boost

 

hey man I'm back with some news, so I left the car's battery unplugged overnight the other day and iv'e been driving the car a lot since then and the boost never went back down anymore! i hope it stays that way! try doing the same thing and see if it fixes your issue

 

l think l have a leak somewhere.

 

my car's vacuum hoses didnt have clamps when i purchased it (previous owners eh?) i picked up some clamps and put them on every end of the hose i saw and it seems like it helped, check if your car is missing clamps on the vacuum lines. My CBV hose used to jump out cause it didnt have a clamp, dangerous.

 

my hoses are on very tight l have to use alot of force to unhook it. l will be looking at my intercooler if it does have a leak.

 

have you tried the starter fluid method?