98 S70 T5 Boost problems- possible CBV?

captainkong · Post by **captainkong** » 23 Sep 2015, 00:42

Hey everyone, I'm having a boost problem with my 98 s70 T5 auto(160k). When I floor it at about 25 mph I'll boost up till about 45-50mph, once It shifts into 4th there is no more boost.

Now when I floor it at about 40 mph I get no boost at all and the rpms move slowly. Also feels like my engine is bogging down a bit.

I've noticed my car has been getting harder to start over the course of the last month or so... taking a couple of seconds to start up. Sounds like its struggling to turn on. I never have to crank it more than once but its definitely taking longer( this is only on a cold start)

At this point I'm thinking it's my cbv and or fuel injectors. Can someone give me a little insight on this?

If it is my cbv, why would I be able to boost early on and then get absolutely no boost when I floor it at 40?

Thanks for your time everyone.

Post by **rspi** » 23 Sep 2015, 07:34

Likely a bad turbo tube.

Post by **tryingbe** » 23 Sep 2015, 07:48

Could be a clogged catalytic converter too.

captainkong · Post by **captainkong** » 24 Sep 2015, 06:44

Thanks for the videos. I'll talk a look at my hoses after work tomorrow. I replaced some of the hoses by the engine with silicone, but haven't checked the one by the one by the turbo.

As for the cat, how would I go about determining if It is it? I haven't seen any threads about cat problems with the same symptoms as mine.

Post by **tryingbe** » 24 Sep 2015, 10:04

captainkong wrote: As for the cat, how would I go about determining if It is it? I haven't seen any threads about cat problems with the same symptoms as mine.

Unbolt the downpipe and take it off for a quick test drive.

http://volvospeed.com/vs_forum/topic/17 ... heck-next/

1ezliving4ume · Post by **1ezliving4ume** » 24 Sep 2015, 11:22

The CBV is easy to check and it sounds as if that could be the problem. When I opened mine up the diaphragm was sucked in, not good

captainkong · Post by **captainkong** » 28 Sep 2015, 03:04

I inspected ALL my hoses related to the turbo and intercooler and surprisingly nothing was torn or had damage...Only thing is I have some pretty rusty clamps down by the turbo.

After doing some more research it seems very likely it could be both my cat and cbv causing me problems. I'll attempt to remove the down pipe Wednesday when I have some time.

If I don't notice much of a difference in performance after I unbolt my downpipe would it be safe to say my problem lies with the cbv?

I will also post a video today/tomorrow showing how its acting. Hopefully that will give some better insight to my problem

thanks everyone.