Bpc576

low boost

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so my 2000 s40 is not boosting like it should. i installed a boost gauge today finally. i tapped it into the far back vacuum line on the manifold above the throttle body. it shows at full throttle in sport mode im only boosting maybe 5 of 6 psi max. its the same amount of boost i was getting off the obd2 reader before i installed the boost gauge so i know i didnt cause a vacuum leak. i also know i dont have any detectible vacuum leaks that i could find. could it be wastegate? thanks guys!!!!!

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On ‎1‎/‎3‎/‎2017 at 5:34 AM, Diio said:

try to just screw in the wastegate arm abit :)

I concur.  There's a great how-to from iPD on how to adjust the waste gate to properly function as it's meant to.  And you don't need their expensive special tool to do this either.  I made my own manual powered adjustment tool using a blood pressure cuff bulb pump, a Mr Gasket brand 0-15psi gauge (which is marked in ½ psi increments) and some silicon tubing to adjust the waste gate on my S60's turbo.  Just attach to the waste gate hose and you can see at that PSI the waste gate actuator arm begins to move.  Then you can adjust the arm from there so that the waste gate valve is CLOSED when the actuator diaphragm is fully retracted.  The arm should then begin to move at the proper listed PSI value that iPD gives.

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When I emailed IPD last year asking for the value for the nedcar they told me I couldn't use it and that the procedure required special tools.

My question:

Looking at the wastegate adjustment tool, saw the instructional video for it, your pdf chart supplies a bunch of good values for desired psi based on model #'s, has anyone inquired in the past what the psi should be for the nedcar s40/v40, B4204T 3/4 ? It is not in the list unfortunately for me.

Their response:

The adjustment procedure isn't on there because it is very complicated and requires special tools. We recommend a dealer for any adjustments needed but unless you are experiencing problems, it most likely doesn't need to be done. 

Ron Wyman
Customer Service Agent

I know I saw some fun stuff for sale on a facebook group forever ago for it. There is a UK post with someone asking and mentioning the IPD chart (which at the time must have listed the nedcar engines) and they were discussing how IPD was US and didn't have values for the T4.

Their current youtube vid does not show the nedcar engines. I can't find the pdf or the tool on their site at the moment.

This is the uk boards post - http://www.volvoforums.org.uk/showthread.php?t=160696

This is a snapshot from the youtube vid

yKodA26.png

 

 

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There is an ancient post on here somewhere with a manual boost gauge tool and saying that the boost at the turbo is .3 bar which 4.3 psi... which seems terribly high.

Still it might be worth hooking something up and seeing where you are currently to baseline it before you start spinning the doodad.

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5.5psi is stock wastegate pressure.  I know this because there used to be an MBC thread and I can attest to the numbers.

When setting the MBC with the TCV bypassed you start with the MBC all the way open which will effectively default to wastegate pressure.  Then montitoring with an actual boost gauge and not some obd Bluetooth BS gradually close the MBC till desired boost is achieved.

with the MBC open boost would build to 5.5psi (3psi lower than stock) and the wastegate would open.

 

in short get a boost gauge hooked up, bypass your TCV and do some 3rd gear pulls.  If you see less than 5.5psi your wastegate is the issue.

 

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This was the ancient thread I was talking about btw. Not sure if it's the same one noodle was mentioning.

 

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Oh the TCV bypass trick!  Ran that on my 40...  Wish I could with my 60...  *sigh*

That chart, what I gathered from analyzing it (besides that it's for the 5-cyl motors more-less) is that waste gate will always be 1.8psi for LPT models (2.5T), and 4.4psi for HPT models (T5 and R)  Also of note, when I adjusted mine on my S60, strangely my motor is NOT listed on there, the B5254T2...  When I adjusted mine however (it's the clip pin style attachment to the actuator arm) it's ~1.8psi just like I had thought it would be.  I don't see why adjusting the 1.9T S40 motors wouldn't be the same sans for maybe a different psi value?  I do recall anywhere it was mentioned, the value was about 5.5psi like stated above...  I never had the chance to delve into mine when I had my S40 unfortunately.  I just ran the original motor balls to the walls at 17psi using a MBC, lol!  :ph34r:

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I thought that the wastegate trick works only for a while until the computer compensates for the added boost, negating the affect.

 

If your boost is low it may be your TCV or a leak in your intake plumbing.

Stan

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19 hours ago, sks40 said:

I thought that the wastegate trick works only for a while until the computer compensates for the added boost, negating the affect.

 

If your boost is low it may be your TCV or a leak in your intake plumbing.

Stan

This I would highly look into as well.  The vacuum lines as well as intake and I/C plumbing are always the first places that you want to look when investigating low boost problems.  TCV is a common item to go out unfortunately (I have a good working spare one that I don't need anymore) and of course rubber hoses and lines are susceptible to high heat like our engines produce.  That all said, the wastegate CAN in fact get out of tune so to speak.  iPD wouldn't make a tool or tutorial about it if it wasn't the case.  I can attest to this also after adjusting the waste gate on my current S60, as when supposedly fully closed, it was in fact not and was just a pinch open with no throttle input and thus needed adjusting to get back to being fully closed with the waste gate diaphragm fully compressed.  I don't know if it's due to the diaphragm getting lazy and old after time and heat or what causes this, but it does happen.  Before adjusting mine, I had some noticeable turbo lag and now not so much.  I'm having some low boost issues myself currently, but it's more than likely a vacuum line or intake / I/C hose leak issue.

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