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Marco's 2003 V70 T5 journey

Help, Advice, Owners' Discussion and DIY Tutorials on Volvo's stylish, distinctive "P2" platform cars.

2001 - 2007 V70
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Marcobrick
Posts: 329
Joined: Tue Sep 28, 2010 9:44 pm
Year and Model: 2003 V70T5
Location: Christchurch,New Zealand
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Marcobrick

Re: Marco's 2003 V70 T5 journey

Post by Marcobrick » Sun Nov 10, 2019 1:24 pm

Well folks, it’s been a while since I’ve posted any progress so I guess it’s time for a catch up. I have a good excuse though. We’ve been very busy with garden and landscaping projects with Spring being upon us.

I took a punt on the boost pressure sensor not giving the correct information and it looks like I was on to something. I fitted a new one, went for a drive and... WOOOOOAAAHHHH! the boost is back in town!

There is still slight jerkiness at low throttle though, but in BREAKING NEWS it appears that I have a leaking brake booster! Sigh. This could be contributing to the jerky herky? Thoughts?


The Fleet:
2003 V70 T5
2014 Nissan Leaf
1973 Fiat 125
1970 MGB GT
Previously:
1996 850R sedan
1994 850T5 Sedan
1995 850 Turbo Wagon
1998 V70T5

Favourite line: "How hard can it be?"

Marcobrick
Posts: 329
Joined: Tue Sep 28, 2010 9:44 pm
Year and Model: 2003 V70T5
Location: Christchurch,New Zealand
Has thanked: 3 times
Been thanked: 0
New Zealand
Marcobrick

Re: Marco's 2003 V70 T5 journey

Post by Marcobrick » Sun Nov 10, 2019 8:23 pm

I have done some more investigating.

I ordered a mechanical boost gauge some time ago and this morning I have fitted it (temporarily)
Idle vacuum (hot) 16in hg
Removed rubber tail from brake booster and capped hard line, idle vacuum 18in. We have a leak (booster is leaking) The joint between the rubber hose and the plastic plug from the booster was quite loose. I tightened the oetiker clamp as much as I could and pressure tested it under water with my Mityvac (everyone should have one) and no more leak. I also tested the hard lines and the check valve and all is well, no leaks, check valve works perfectly.
Reconnected the booster, and idle vacuum still 18 in. Win! ( booster still leaks down after 2 minutes though, so sad face)

I am confident the booster vacuum leak is not significant enough from an engine vacuum point of view to cause any running issues.

Right, now let’s see how much boost we’re actually making.. turns out quite a LOT!
Under moderate load (careful throttle application) it builds to and holds at 11-12psi
Floor it and it goes to 15 psi and sloooooowly comes back to 11
Nail the throttle and pin it and it goes over 20 and doesn’t come back!!

Am I getting enough wastegate travel? Let’s find out. Bridge the yellow and red TCV lines and you have full boost straight to the wastegate actuator. Test drive again and maximum boost tops out at 9 psi, so no problem there me thinks. That leaves the TCV. It’s brand new. But wait, I have a spare. Nope same massive overboost.

Help me out here please... In the past, I have experienced failing TCV on a first gen V70 and older BCS on one of my 850’s. This tended to result in a boost deficit, not a surplus, and that seems to be what others report also.
What is going on?


The Fleet:
2003 V70 T5
2014 Nissan Leaf
1973 Fiat 125
1970 MGB GT
Previously:
1996 850R sedan
1994 850T5 Sedan
1995 850 Turbo Wagon
1998 V70T5

Favourite line: "How hard can it be?"

Marcobrick
Posts: 329
Joined: Tue Sep 28, 2010 9:44 pm
Year and Model: 2003 V70T5
Location: Christchurch,New Zealand
Has thanked: 3 times
Been thanked: 0
New Zealand
Marcobrick

Re: Marco's 2003 V70 T5 journey

Post by Marcobrick » Mon Nov 11, 2019 3:58 pm

Today I thought, what if the wastegate initial pressure is wrong? I have quadruple checked this but it’s easy to do. It’s still set at 4.5 psi exactly. What if I do something rash, like lengthen the rod 3 full turns? Well, 3 turns takes the initial pressure to exactly zero.
Predictably that made it a bit more sluggish off the line but it still overboosts the same as before.

I didi a few more test runs and it’s really strange. Pulling in third gear it holds 11psi holding, holding, holding and then suddenly as if the car’s brain says “oh, I give up!” there’s a great rush as the boost runs away.


The Fleet:
2003 V70 T5
2014 Nissan Leaf
1973 Fiat 125
1970 MGB GT
Previously:
1996 850R sedan
1994 850T5 Sedan
1995 850 Turbo Wagon
1998 V70T5

Favourite line: "How hard can it be?"

User avatar
abscate
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Posts: 18944
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abscate

Re: Marco's 2003 V70 T5 journey

Post by abscate » Mon Nov 11, 2019 5:53 pm

Yikes. The only thing stopping you from blowing a rod is the CBV. I hope that is working well.


Empty Nester
A Captain in a Sea of Estrogen
1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 BMW
Link to Maintenance record thread
Link To Volvo Glossary

Marcobrick
Posts: 329
Joined: Tue Sep 28, 2010 9:44 pm
Year and Model: 2003 V70T5
Location: Christchurch,New Zealand
Has thanked: 3 times
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New Zealand
Marcobrick

Re: Marco's 2003 V70 T5 journey

Post by Marcobrick » Mon Nov 11, 2019 6:40 pm

abscate wrote:
Mon Nov 11, 2019 5:53 pm
Yikes. The only thing stopping you from blowing a rod is the CBV. I hope that is working well.
Brand new, fitted recently, but you never know. Actually, maybe it’s not working, because I don’t think it’s meant to hold 20+ psi (stock part)


The Fleet:
2003 V70 T5
2014 Nissan Leaf
1973 Fiat 125
1970 MGB GT
Previously:
1996 850R sedan
1994 850T5 Sedan
1995 850 Turbo Wagon
1998 V70T5

Favourite line: "How hard can it be?"

User avatar
RickHaleParker
Posts: 3156
Joined: Mon May 25, 2015 2:30 pm
Year and Model: See Signature below.
Location: Kansas
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RickHaleParker

Re: Marco's 2003 V70 T5 journey

Post by RickHaleParker » Tue Nov 12, 2019 7:50 am

Marcobrick wrote:
Mon Nov 11, 2019 6:40 pm
I don’t think it’s meant to hold 20+ psi (stock part)
B5234T3 Maximum boost pressure: 184 ± 10 kPa @ 5100 RPM. (26.687 ± 1.450 PSI)


Platform: P80 1998 C70, B5234T3, AW50-42, Bosch Motronic 4.4, Special Edition package, Plant: Uddevalla Sweden.

Platform: X40 (Nedcar) 2003 S40, B4204T3, AW55-50/51SN, Siemens EMS 2000. Plant: Born Netherlands.

Platform P2 2005 XC90 T6 Executive, B6294T, 4T65 AWD, Bosch Motronic 7.0, Plant Torslanda Sweden.
----------------------------------------------------------------
1997 S90, B6304S, AW30-42, Bosch Motronic 4.4 - Sold

Marcobrick
Posts: 329
Joined: Tue Sep 28, 2010 9:44 pm
Year and Model: 2003 V70T5
Location: Christchurch,New Zealand
Has thanked: 3 times
Been thanked: 0
New Zealand
Marcobrick

Re: Marco's 2003 V70 T5 journey

Post by Marcobrick » Wed Nov 13, 2019 12:34 am

RickHaleParker wrote:
Tue Nov 12, 2019 7:50 am


B5234T3 Maximum boost pressure: 184 ± 10 kPa @ 5100 RPM. (26.687 ± 1.450 PSI)
Is that absolute manifold pressure? It would make sense because that would equal about 12psi of boost


The Fleet:
2003 V70 T5
2014 Nissan Leaf
1973 Fiat 125
1970 MGB GT
Previously:
1996 850R sedan
1994 850T5 Sedan
1995 850 Turbo Wagon
1998 V70T5

Favourite line: "How hard can it be?"

User avatar
abscate
MVS Moderator
Posts: 18944
Joined: Sun Feb 17, 2013 5:54 pm
Year and Model: 99T5 ,99S70,2005V70
Location: NYC, ALBANY NY
Has thanked: 222 times
Been thanked: 739 times
Trinidad & Tobago
abscate

Re: Marco's 2003 V70 T5 journey

Post by abscate » Wed Nov 13, 2019 2:34 am

I think that is absolute pressure as you note. Good catch.


Empty Nester
A Captain in a Sea of Estrogen
1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 BMW
Link to Maintenance record thread
Link To Volvo Glossary

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RickHaleParker
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Re: Marco's 2003 V70 T5 journey

Post by RickHaleParker » Wed Nov 13, 2019 9:20 am

Marcobrick wrote:
Wed Nov 13, 2019 12:34 am
Is that absolute manifold pressure? It would make sense because that would equal about 12psi of boost
It does not say atmospheric or absolute. However 27 absolute would correlate with observed 10 - 12 atmospheric.


Platform: P80 1998 C70, B5234T3, AW50-42, Bosch Motronic 4.4, Special Edition package, Plant: Uddevalla Sweden.

Platform: X40 (Nedcar) 2003 S40, B4204T3, AW55-50/51SN, Siemens EMS 2000. Plant: Born Netherlands.

Platform P2 2005 XC90 T6 Executive, B6294T, 4T65 AWD, Bosch Motronic 7.0, Plant Torslanda Sweden.
----------------------------------------------------------------
1997 S90, B6304S, AW30-42, Bosch Motronic 4.4 - Sold

User avatar
abscate
MVS Moderator
Posts: 18944
Joined: Sun Feb 17, 2013 5:54 pm
Year and Model: 99T5 ,99S70,2005V70
Location: NYC, ALBANY NY
Has thanked: 222 times
Been thanked: 739 times
Trinidad & Tobago
abscate

Re: Marco's 2003 V70 T5 journey

Post by abscate » Wed Nov 13, 2019 11:56 am

Its a quirk of Volvo that everything is measure in absolute pressure in software and diagnostics, isnt it?


Empty Nester
A Captain in a Sea of Estrogen
1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 BMW
Link to Maintenance record thread
Link To Volvo Glossary

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