Lost PSI on Turbo Boost

Post by **phils94850** » 21 Mar 2010, 13:54

yep you got it then... when you disconnect that hose you should be able to get basically as much boost as the turbo can muster. The triangular piece " i think " is basically like a factory BOV and id say yes if its ripped it can cause you boost problems.
With that hose disconnected you should be able to get more than 12psi. Soooo either you have a boost leak or mechanical problem at the turbo. I dont think you have boost leak though, my old 850 had a boost leak at the hose going to the throttle body and i couldnt build more than 5psi.

Post by **MadeInJapan** » 21 Mar 2010, 21:19

Hmmm, maybe time for a new turbo or maybe I'll try the rebuild kit.... The fun continues.

Post by **jblackburn** » 22 Mar 2010, 08:18

Before you go about rebuilding the turbo...how old are your lines? Silicone hose is cheap, and it may be worth replacing them. Or it could just be your turbo control valve is getting old, I've been looking into one of these for mine: http://www.ipdusa.com/product.asp?strPa ... rtRecord=1

Post by **MadeInJapan** » 22 Mar 2010, 14:48

Yes, I have that control valve from IPD...tried the old one too- no difference.
Also, all of my lines are silicone already- as well as all my turbo hoses.

Post by **MadeInJapan** » 22 Mar 2010, 17:24

Okay, figured it out!
Good news and bad...
I took the heat shield off and tried to work the actuator rod to the wastegate- I was able to move it without to much force. I shouldn't be able to do that, which means the diaphragm in the actuator or the spring is bad and isn't holding the wastegate closed. I'm in search for a new actuator now (as from a call to IPD I understand that that part is not serviceable). Anyone know of a spare lying around. I think they're the same from an '94-'96 850 turbo and my '98 S70 turbo (G15 or T16 Mitsu turbo). I'll put an ad up here later asking for one too.

Post by **vegasjetskier** » 22 Mar 2010, 19:43

MadeInJapan wrote:Okay, figured it out!
Good news and bad...
I took the heat shield off and tried to work the actuator rod to the wastegate- I was able to move it without to much force. I shouldn't be able to do that, which means the diaphragm in the actuator or the spring is bad and isn't holding the wastegate closed. I'm in search for a new actuator now (as from a call to IPD I understand that that part is not serviceable). Anyone know of a spare lying around. I think they're the same from an '94-'96 850 turbo and my '98 S70 turbo (G15 or T16 Mitsu turbo). I'll put an ad up here later asking for one too.

Dave,

Why would the actuator fail right when you had your engine fixed? What could the mechanic do that would ruin it?

I would think that it's more likely that the vacuum hoses are mixed up or a wire to the TCV is broken. I read somewhere that when the TCV fails the turbo defaults to a low pressure setting to prevent blowing the engine.

If you can't get the actuator through the ad here, you could try www.vandsautodismantlers.com or www.erievovo.com.

Post by **MadeInJapan** » 22 Mar 2010, 20:09

Hey Vegas,
I don't know what might have happened. My experience is that some things just happen randomly. I tried a different TCV that was known good and there was no change. I also disocnnected the hose to the actuator (which would have boosted full for the turbo- like no TCV was connected at all, and there was no change...I have also checked and double checked my hoses. The mechanic claimed he never touched the turbo, but my suspicion is one of his workers might have messed with things- who knows. Anyway, the actuator rod can be pushed in easily and this isn't normal. I found one on eBay but they want to much for it. I think I've located one here locally off an old 850 turbo, but if that doesn't work out, I'll try the places you mentioned. Thanks!
Dave

Post by **MadeInJapan** » 28 Mar 2010, 06:30

Quick update. I mistakenly thought the actuator was bad. It is NORMAL to be able to pull out on the actuator rod- just not in very easily. Since I could pull out on it, I thought it was bad but it wasn't. So I got a good used one from a member on VS (not expensive) and then I took the heat shield off again to change it out when I noticed a broken vacuum line just to the left of the actuator that goes straight to the front of the intake manifold. Anyway, after repairing that hose, all is well again! So, if you're having boost problems, my suggestion is to pull on all of your vacuum hoses (and make sure your turbo hoses are fine) and see if any are disconnected. It's amazing what one small vacuum line disconnected does to bleed off your boost. So, if anyone needs a turbo actuator, I have a spare laying around now.

SkyVolvo · Post by **SkyVolvo** » 11 Apr 2010, 17:44

Hey,
My '94 850 Turbo Wagon has been having odd turbo problems - it was working earlier today, and then when I took it back out a few minutes ago, no boost - it'll build turbo compression right up to the white line, but it won't kick in.

It had done this a few weeks ago before I embarked on a long PCV repair journey. Turbo, then CELs for o2 sensor and cat. converter, and no turbo. I had the battery detached for a long time, which I'm guessing reset something that allowed the turbo to work again for awhile until God-knows-what shut it down again.

I would love for it to be a vacuum line. I've triple checked every vacuum line associated with the PCV work - everything coming off the vacuum tree, the brake booster line, the ptc connections, and the two lines coming off the front of the intake. It sounds like there are more lines coming off of the turbo underneath the heat shield - when my engine cools down, is that where I should look?

Post by **osman** » 01 Jan 2013, 17:33

Did you ever figure it out?
If so what was the problem I am having a similar issue.

Lost PSI on Turbo Boost

Re: Lost PSI on Turbo Boost