[gr82882]

Hi Everyone,

Here is my story: A couple of days ago, I noticed that a rubber elbow that attaches to the passenger side of the intake manifold (between the manifold and the power steering pump) had worn away and become comletely disconnected. This made sense beacuse my car was only getting around 4-5 psi of boost. After hours of trying, I was unable to get the new elbow in there, so I ran a completely new vacuum line (along a different route). After doing that, I noticed no difference in boost pressure (still around 4-5 psi).

After this, I decided to try out my new Dawes Devices manual boost controller. To install it, I disconnected the line from the wastegate, pluged that into the MBC, and put a hose from the other end of the MBC into the wastegate (I think this is how it is supposed to be installed, but correct me if i'm wrong, please). After installing the MBC, i noticed absolutely NO difference, so I decided to adjust it. After adjusting the MBC as far as it would go, i STILL only get around 4-5 psi. I am very frusterated w/ the whole thing, and I'm out of ideas. Do any of you have any ideas as to what I should try next?

I look forward to your responses.
-Greg

 

[Prospero]

Sounds like you have more leaks. Try looking at all "boost" hoses to and from the intake to turbo. I've had to replace all of mine before. In some cases I couldn't build good boost and in other cases the car would not run at idle. Check each hose with your engine cold and feel every inch of the hoses with your hands. The hole could be quite small and hard to see without the turbo pushing boost through it. By feeling all of the hoses and checking the connections, you should be able to find the issues. If that doesn't work then let me know.

Cheers
Prospero

 

[gr82882]

Thanks Prospero!

On three message boards, you are the only one that has given me a decent reply. Quick question for you... I know that the vacuum leak that I fixed I would have never found if it weren't for Bay 13. Are there any other lines that are hard to find like that one was? I will check all of the lines that come out of the solenoid, and all of the lines that are on the "vacuum tree" that is under the throttle body cover, but are there any others, say underneath the car or anything? Thanks a bunch.

-Greg

 

[Prospero]

So far, it sounds like you've seen them all. I have replaced all of my lines at about 175K miles and still get ~30 MPG highway. There are, now that I think about it, more vacuum lines in and around the top of the intercooler and going under the battery tray. The best method of locating vacuum leaks is to use "gum cutter" and spray it around the possible leak areas with the motor at idle. Any change in RPM generally indiactes a leak. Spray again in the same area a few times to make sure it's that spot which is causing the RMP change.

Yeah...Volvospeed is a great resource to have on the net. And yeah...I know what you mean about people not giving replies too often about questions such as yours. But...hey...anytime I can help...

Prospero

 

[Prospero]

Oh...and one more thing. I suggest using the silicone type vacuum hose found at car-tuning shops and such. The natural rubber hoses from Volvo start to go every few years or so. The cost difference will not be that much if you are going to go all the way. It seems that you can find these hoses in kits at any decent auto-parts shop.

Cheers
Prospero

 

[gr82882]

One other thing Prospero...

My friend (who's advise I take lightly) suggested that I should disconnect the hose that goes to the wastegate completely. He said that by doing this I should see maximum boost. I know you arent' supposed to do this, but I tried it anyways, just for testing purposes. It made no difference at all. Still around 4-5 psi. Does this make sense if I have a vacuum leak? He says it's because my turbo is going bad. I hope not, and I've not seen any of the tell-tale signs such as a whining sound, or smoke coming out of the exhaust. Let me know what you think, and thanks again.

-Greg

 

[Prospero]

Pulling the vacuum hose off of the wastegate will produce max HP for a while. The ECU will give the CE light after it notices that there is no control over the wastegate function. This is only suggested for testing only though. Don't leave the hose off for normal driving, it's just not too good for the car.

Regarding the root cause...the turbo could be going bad. But I doubt it. Every time I've ever had a boost issue it has been due to a hose. When I suggest to check all of the hoses by hand, I meant check all of the hoses that come out of the turbo and into the IC and then into the throttle body. There are something like 18 places where hoses are connected with a hose clamp. There are also many rubber hoses (about 2" dia.) which are prone to leak. Look and feel every inch of these first. (Hint...if your engine bay is clean, look for any oily areas. The leak usually will leave a bit of residue near by.)

I've had the Volvo dealer tell me that my turbo was dead and they needed to replace it for big $$$. I figured that I'd replace the turbo myself to save money. I went back to the dealer to get my car and paid for their 1-hour of labor to inspect and diagnose the issue. They were 100% sure that the turbo was gone. So I went and got a turbo from a close friend. Took the car to my shop and pulled the turbo off. Installed the turbo and figured I was done. I started the car just to have the EXACT SAME PROBLEM as I did before replacing the turbo. Pissed as hell, I pulled off each and every IC hose and pipe. That's when I found a hole in the IC hose going into the throttle body and IAM. Replaced the hose for $54.00 and had full boost once again. I then asked the dealer to inspect the turbo for damage or issues. (I told them it was the replacement.) They gave me 100% good and said to use the turbo to replace the defective one on the car. When I told them that the turbo they were holding was in-fact the one they told me to replace. I gave them the old hose and they provided excuses. Needless to say, that wasn't the first time they were found to be full of crap.

Long-story...but do the extra work now and save yourself time and money.

Cheers,
Prospero

 

[gr828822]

Re: (Prospero)

Hello Again. I forgot my password, so now I'm gr828822. Anyways... a little update. I checked the hoses that go from the turbo, into the intercooler, then into the throttle body, and they seemed ok. I also replaced the three lines that come out of the BCS, and the line that goes from the intake manifold to the turbo. I still only see 5psi of boost. Is there any way for me to pressurize those lines to see if they are leaking? Do you have any other tips, or things that I should look for?

I look forward to hearing your response.
-Greg