IPD sale Volvo Parts
XeMODeX - Experts in Volvo Electronics My Swedish Parts ad - genuine Volvo parts
Did you know? 🤔
Logged in users can get email notification of topic replies Log in or register (free).
Amazon Link Buy your stuff using this and it helps MVS!

'94 turbo control vac lines Topic is solved

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

User avatar
BlackBart
Posts: 384
Joined: Sat Dec 10, 2016 5:03 pm
Year and Model: 2004 XC70 BlackBetty
Location: Montana
Has thanked: 25 times
Been thanked: 17 times
Sweden
BlackBart

'94 turbo control vac lines

Post by BlackBart » Mon Aug 05, 2019 12:16 pm

I've had a funny random stumble with my 850T on acceleration, like a cracked boost hose. Sunday I dove into finding a hose leak or intercooler hose problem.

Found one of the vac lines broken in half at the clip on the rear of the head, others seemed pretty dried out.

My question is about the routing and connection of those hoses.
Here's the diagram of those three hose connections...
vacuum-hose-diagram-850.jpg
vacuum-hose-diagram-850.jpg (104.59 KiB) Viewed 106 times
The lower hose (yellow this diagram) goes to the boost control body, the middle (blue here) goes to the intake hose close to the filter box, and the upper (green here) goes to the bottom of the turbo body. (hard to get to that one from under the car).

I checked mine before I took anything apart, and the upper and lower hoses were flipped from this diagram. The parts diagrams I have don't name body #16 where they all connect. Are there ports inside it that route the vacuum from one hose to another, depending on what the switch tells them? Is it just a hollow body and it doesn't matter where the hoses connect?

I've had this car a long time, and I'm sure the first owner never touched any of this at 60k miles, so I doubt it was changed.

So I hooked them up per the diagram. Only drove down to the gas station so far, but nothing funny in how it ran, and I had good acceleration. (Also tightened all boost hoses I could reach and checked for cracks)


Old & Busted
IMG_4143.JPG

Other end broken off
IMG_4145.JPG
They were all dry and just snapped off.
IMG_4150.JPG
All new. My blue goes to the bottom of the turbo housing. My red goes to the inlet hose. My yellow goes to the boost control body.
IMG_4152.JPG
IMG_4153.JPG


ex-1984 245T wagon
1994 850T wagon
2004 XC70 wagon
Want: '67 122 wagon

User avatar
greg850r
Posts: 190
Joined: Thu May 03, 2012 5:06 pm
Year and Model: a long list
Location: Mo
Has thanked: 1 time
Been thanked: 4 times
United States of America
greg850r

Re: '94 turbo control vac lines

Post by greg850r » Mon Aug 05, 2019 3:22 pm

I just walked out and looked at 2 different of my 96 850 turbos and noted;
top line to pull off,
middle to air cleaner,
Bottom line to turbo body at the bottom.
That diagram does not match my cars. I think I remember there are 2 diagrams for 2 different year TCVs though and some cars are plumbed the other way. Perhaps the 94 was different and your diagram is correct for your year. Maybe they changed it for 95-96. Someone else here probably can confirm this.

Edit: While you are replacing the lines there is a 4th one coming from the middle of the turbo toward the motor (red one in your diagram) that goes around the driver's side of the head and connects at the intake for full time vacuum. It's probably as bad as the others.


05 Cross Country wagon
99 C70 Convertible
96 850R wagon
96 850T wagon
96 850 GLT 5spd N/A sedan
97 850R 5spd sedan
66 GTO 421SD 4spd
67 GTO 455 T400
02 Powerstroke 4x4
85 Yota 4x4
24' 454 Challenger
07 Softail Custom
02 Sportster Custom
Parts cars not included

User avatar
abscate
MVS Moderator
Posts: 17913
Joined: Sun Feb 17, 2013 5:54 pm
Year and Model: 99T5 ,99S70,2005V70
Location: NYC, ALBANY NY
Has thanked: 193 times
Been thanked: 620 times
Trinidad & Tobago
abscate

Re: '94 turbo control vac lines  Topic is solved

Post by abscate » Mon Aug 05, 2019 8:52 pm

You have found the other one of the 6 hose connection permutations that will work as planned.

The turbo control valve connects pressure from the turbo spool to either the waste gate (red) or dump (blue)

If the spool pressure (green) and waste gate lines are switched, the valve is connecting them exactly the same.

the other four combinations of hoses will not work correctly'

True mathematicians will cringe at my use of the words permutation and combination here, but thats why Nobel doesn't give out a prize in Math - the world hates you all, since you neither exist nor are you unique.


Empty Nester
A Captain in a Sea of Estrogen
1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 BMW

User avatar
BlackBart
Posts: 384
Joined: Sat Dec 10, 2016 5:03 pm
Year and Model: 2004 XC70 BlackBetty
Location: Montana
Has thanked: 25 times
Been thanked: 17 times
Sweden
BlackBart

Re: '94 turbo control vac lines

Post by BlackBart » Tue Aug 06, 2019 3:36 pm

Where does that leave my son the fizziks major?

So my combination is ok, that's good. That diagram came from the 1994 files at Volvo parts webstore...
https://www.volvopartswebstore.com/show ... evel=24662

Greg - I saw that fourth hose back there. It was better than the others but I should probably change it too. I think I have enough of the blue left on the spool.

Thanks!


ex-1984 245T wagon
1994 850T wagon
2004 XC70 wagon
Want: '67 122 wagon

User avatar
BlackBart
Posts: 384
Joined: Sat Dec 10, 2016 5:03 pm
Year and Model: 2004 XC70 BlackBetty
Location: Montana
Has thanked: 25 times
Been thanked: 17 times
Sweden
BlackBart

Re: '94 turbo control vac lines

Post by BlackBart » Wed Aug 07, 2019 6:31 pm

Wow what a blast! This thing is quick!

I forgot what a solid car this was and how fun to drive. So much lower than the XC.
My engine is relearning the correct A/F mixture without a vac leak - my range went from 30 miles (yike) to 40, 50, 70, 90, 105 while I ran errands and zipped out the freeway to the airport. Stood on the brakes a few times to clean off the rotors. One might be sticking a bit.


ex-1984 245T wagon
1994 850T wagon
2004 XC70 wagon
Want: '67 122 wagon

User avatar
erikv11
Posts: 9103
Joined: Sat Jul 25, 2009 2:03 pm
Year and Model: 850, S/V70, 06 S60R
Location: Iowa
Has thanked: 55 times
Been thanked: 189 times
United States of America
erikv11

Re: '94 turbo control vac lines

Post by erikv11 » Thu Aug 08, 2019 9:00 am

Wandering off topic but: watch for rusting aftermarket caliper slide pins. Factory and 25 years old are not much of a worry, but if the calipers have ever been replaced then I'd pull them and grease them now.
These users thanked the author erikv11 for the post:
BlackBart


'95 854 T5-R, Motronic 4.4, 185k
'96 855 NA, 140k
'98 S70 NA, 210k (living out west)
'98 V70, T5 tune-injectors-turbo, LPT engine, 280k
'06 S60 R, 160k
gone: '96 NA 850 210k, '98 NA V70 182k

User avatar
BlackBart
Posts: 384
Joined: Sat Dec 10, 2016 5:03 pm
Year and Model: 2004 XC70 BlackBetty
Location: Montana
Has thanked: 25 times
Been thanked: 17 times
Sweden
BlackBart

Re: '94 turbo control vac lines

Post by BlackBart » Thu Aug 08, 2019 12:44 pm

OK, I'll look at that, thanks. It's been sitting for a while.


ex-1984 245T wagon
1994 850T wagon
2004 XC70 wagon
Want: '67 122 wagon

Post Reply