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96 850 Turbo Wagon Mechanic's Challenge

Help, Advice and DIY Tutorials on Volvo's P80 platform cars -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, including 850 R, 850 T-5R, 850 T-5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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FlipIt
Posts: 78
Joined: 2 January 2011
Year and Model: 96 850 T Wagon
Location: Greenville, SC

Re: 96 850 Turbo Wagon Mechanic's Challenge

Post by FlipIt »

My coolant pressure test finally passed so I installed the exhaust system with new gaskets, connected the turbo lines, connected the air tubes, added coolant and engine oil, installed and connected the battery. I cycled the ignition key a few times and checked for fuel leaks. Then I cranked the starter and the engine immediately started even though it hadn't run for a couple weeks. No exhaust leaks at the exhaust manifold, turbo or down pipe! No coolant leaks where the coolant pipe attaches to head or at the turbo. No engine oil leaks at the turbo or where the drain line enters the pan! No ATF leaks! I am very pleased!

The engine idled very smooth and quietly. After it reached operating temperature I tried different engine speeds. It was very responsive and sounded strong with no load. I eventually raised the speed to 4,000 rpm and held it there checking for blue or black smoke from the tail pipe but didn't see any. I won't be able to check the turbo boost until I can drive the vehicle and load up the engine.

I purposely left the engine oil dipstick up so the crankcase was vented. As I suspected, once the engine warmed up puffs of smoke emitted from the dipstick. This means that the crankcase ventilation system is clogged. I know the path is open at the main intake fitting because I soaked the fitting with SeaFoam and blew thru it with a test hose. No doubt the crankcase ventilation system is clogged so today I removed the intake manifold. I noticed that one of the grommets/insulator (not the O ring) is missing between the injector and the manifold so I ordered 5 new ones. They won't arrive until this weekend. I also installed the new torque rod assembly.

FlipIt
Posts: 78
Joined: 2 January 2011
Year and Model: 96 850 T Wagon
Location: Greenville, SC

Post by FlipIt »

I removed the oil trap and using various sizes of hoses was able to easily blow thru all ports in the trap and on the block. I soaked the oil trap overnight with the rest of my SeaFoam, drained it and installed the crankcase ventilation system. Since nothing was blocked I'm hoping my dipstick tube puffs of smoke were due to the pinched hose shown in the photo below.
NoIntake.jpg
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I installed the intake manifold, new injector seals on the fuel rail, the electric cooling fan and shroud, a new throttle body gasket and then connected all of the intake hoses and tubes. I even managed to install the two piece exhaust manifold heat shield that keeps the paint from blistering on the hood. Being almost out of gas I decided to make my first drive to the gas station about 2.5 miles from home.

When backing out of the garage the brakes squealed due to all of the rust on the rotors. By the time I had driven the two blocks in my subdivision the ABS warning light extinguished. I suspect it came on when I ran the vehicle in drive to check the transmission while all wheels were off and the vehicle was sitting on jack stands. Having the front wheels going 25 mph and the rears not moving must have been confusing to the ABS.

Almost as soon as I pulled out of my subdivision and started down the hill toward Wal-Mart's gas station a big arrow on the dash started flashing and the Check Enging light came on. I suspected it was related to the transmission but couldn't confirm that because I had left my owner's manual at home. At the bottom of the hill another symbol illuminated that I thought might be related to my cooling fan. Since the engine temperature was still normal I pressed on. Next the fuel low warning came on but I made it to the gas station without running out of fuel.

I read the DTCs in the parking lot but didn't have my manual to decode the only one shown: P0500

I decided to attempt to return home. Things went OK until I started up the hill to my subdivision entrance. It seemed like the transmission needed to shift down but wouldn't and the engine couldn't pull the hill in overdrive. I shifted to low but could only depress the pedal slightly or the engine would start to stall. Fortunately no one was behind me and I creeped up the hill at 5 mph and then thru the subdivision to my house going 10 mph on level ground. I learned that the flashing arrow indicates automatic transmission fault and P0500 is vehicle speed sensor malfunction. Hopefully, the engine just went into limp mode when the VSS faulted. The other indication was low coolant level because the thermostat opened up dropping the level in the pressurized overflow tank. The wagon is now back in the garage for diagnostics. The first thing to check is the ATF level with the engine warm. I've read that the VSS fault can be triggered by the ATF being only 1/2 quart low. I checked it with the vehicle on jack stands but the vehicle may not have been level.

FlipIt
Posts: 78
Joined: 2 January 2011
Year and Model: 96 850 T Wagon
Location: Greenville, SC

Post by FlipIt »

After some testing I found that the fuel pressure was low again. I determined that the series resistance was high so I pulled the pump and eliminated two of the four mechanical electrical connectors. I ran the engine with a vacuum/boost gauge connected to the engine oil dipstick. From engine cold start to fully warmed the crankcase remained at atmospheric pressure. I also checked the manifold vacuum. The vacuum is a steady 16.5 in. Hg at idle. The vacuum changes briefly to around 13 in. Hg when accelerating and to about 20 in. Hg when decelerating which seems normal.

I need some help correcting the VSS fault. I measured the sensor resistance to be 422 ohms. I read somewhere that the resistance should be from 200 to 400 ohms. Since I don't have a 1996 wiring diagram I traced the wires YEL/GRN and GRN/YEL thru the wiring harness. I was surprised they don't go thru the 26 pin transaxle connector. Nor do they connect to either the TCM or ECM. Instead, they go to a two row connector in the TCM/ECM box that is laying under the mounted TCM and ECM connectors. From there they leave the box in a harness that is attached to the passenger side fender well and then into the firewall. My 1995 wiring diagram has a note that YEL/GRN and GRN/YEL wires go to the speedometer for 1996. The fault (P0500) appears after about one mile of driving whether the VSS is connected or not. The speedometer works but the odometer and trip odometer do not increment. I've read on the forum that the odometer frequently fails after 100,000 miles. Is there a cable from the transaxle that drives it? I haven't been able to locate one coming from the transaxle. I noticed a two wire electrical connector aft and below the VSS but will have to raise the vehicle again to access it. I don't know what it is for.

I'm having trouble removing the VSS. I have the mounting stud/bolt out but can't get any leverage to pry the sensor out. I may raise the vehicle and monitor the VSS output voltage with the vehicle in drive. It's probably a pulsed waveform that may register as AC voltage on a multimeter.

FlipIt
Posts: 78
Joined: 2 January 2011
Year and Model: 96 850 T Wagon
Location: Greenville, SC

Post by FlipIt »

With Ozark Lee's help via PM I was able to remove the left and center vent outlets. On the models with the wood grain trim the left and center vents have no removable enclosure. Instead, the horizontal pivots are just held in place by friction and pull straight out. I pulled mine out with a paint can lid opener.

Following instructions on the forum I removed the dash upper trim panel with air bag and the instrument cluster. The leather trim has pulled away from the air bag corners and part of the main dash and looks bad. The trip and main odometer in the instrument cluster does not increment. I will attempt to repair both using guidance from the forum.

precopster
Posts: 7543
Joined: 21 August 2010
Year and Model: Lots
Location: Melbourne Australia
Has thanked: 8 times
Been thanked: 128 times

Post by precopster »

This post is a great resource for somebody wanting to resurrect pretty much any 850 turbo or n/a. How did you go with the odometer repair?
Current cars VW Transporter 2.5TDI, 2010 XC90 D5 R Design

FlipIt
Posts: 78
Joined: 2 January 2011
Year and Model: 96 850 T Wagon
Location: Greenville, SC

Post by FlipIt »

My wife reminded me of my annual spring yard duties so progress the last month has been slow. I purchased a 1/4 inch diameter 15 tooth plastic gear for the odometer. It cost me $11.50 with free shipping. I installed the gear and manually incremented the odometer to add the miles I've driven since purchasing the wagon. I installed the gear and reassembled the instrument cluster. I tested all of the warning and cluster lights with an ohmmeter and replaced all of the burned out bulb assemblies. I removed the SERVICE bulb since it can only be reset by an authorized Volvo repair shop. I installed the cluster in the vehicle as shown below.
Cluster.jpg
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I was able to remove the passenger air bag without deploying it. I separated the air bag cover from the dash. The photos below show the unsightly bulges in the main section of the upper dash.
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Buldge1.jpg
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When I examined the underside of the dash I found numerous splits in the plastic. I glued the splits back together with superglue and then reinforced them with aluminum flashing stock as shown below.
DashBLft.jpg
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DashBRt.jpg
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This was a tedious and time consuming process.

FlipIt
Posts: 78
Joined: 2 January 2011
Year and Model: 96 850 T Wagon
Location: Greenville, SC

Post by FlipIt »

Next I used two part epoxy to glue the leather bulges to the plastic form as shown below.
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Glue1.jpg
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Even though I waited 24 hours before removing the clamps the glue did not hold to the rubber like substance that is bonded to the underside of the leather. Instead of trying a different glue and chancing it coming loose I decided to "sew" the leather to the plastic. I used 24 gauge galvanized steel solid wire as my "thread". I used my electric drill and a 3/64 inch drill to make a hole for every "stitch". The results are shown below.
DashTRt.jpg
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I doubt the leather will ever separate from the plastic again. The two photos below show how the shrinking leather pulled away from the airbag cover plastic frame.
Curl1.jpg
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Curl2.jpg
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A large section of the plastic was broken completely off on one end and there were cracks on the other end. It was necessary to reinforce the plastic with metal flashing as shown below.
Cover1.jpg
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Even though I tried an adhesive advertised to work on leather and plastic and let it dry for 48 hours the leather began separating from the plastic within two hours after removing the clamps. So I reverted to sewing the leather to the plastic with metal thread as shown below.
Cover2.jpg
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Because the leather had shrunk when I reinstalled the airbag cover into the upper section of the dash there was a gap on the left side as shown below.
Dash1.jpg
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Also, the stitches at the top were more visable than I had planned. So I used two different gauges of wire with black insulation to fill the gaps.
Dash2.jpg
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I attached the wire with adhesive only applied to the dash and not the airbag cover so it would not interfere with the airbag deployment. It's not perfect but I've spent way more time than I planned on this particular task so it will have to be good enough.

SimLyons
Posts: 806
Joined: 3 April 2011
Year and Model: 2001 V70 T5
Location: Newberg, OR (Portland)

Post by SimLyons »

You have incredible commitment to this job along with the patience of Job. And I commend your wife's patience, too. I have learned more about my 850R through your amazing posting than I have from my (difficult) shop manual. Thank you!
Sim

Red-Arrow
Posts: 449
Joined: 26 August 2010
Year and Model: 850 T5 1995
Location: Scotland.
Been thanked: 2 times

Post by Red-Arrow »

You know that you could have just replace the material on the dash for a few bucks?
Life would be enjoyable if it wasn't so painful to live.

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