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Volvo S80 T6 1999 bad start, bad idle after overhaul

Help, Advice, Owners' Discussion and DIY Tutorials on the Volvo S80 model. Sometimes called an "executive car", the S80 was and continues to be Volvo's top-of-the-line passenger car.
Joost
Posts: 21
Joined: Sun Dec 17, 2017 6:24 am
Year and Model: 1999 S80 T6
Location: Netherlands
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Re: Volvo S80 T6 1999 bad start, bad idle after overhaul

Post by Joost »

Hi all, I try to update this thread until the solution is found. Update on the gearbox: it turns out that I mixed up the 2 thinner pipes that you can find under the oil pan, leading to the accumulators. They fit either way, somehow I mismatched them. When I restored it, the gearbox went forward and reverse again. However, I haven't been able to test it fully yet.

Update engine: Because of a persistent DTC 3000, I checked both wires going to the engine speed sensor (pin 48 and 66 on ECU I believe). It turned out fine, I measured 120 ohms through the sensor. I also unplugged the sensor and shorted both ends, leading to 0.3 ohm, which is fine. No leaks to ground. I then put the scope on the relative pins on the harness and cranked the engine. I saw a sine wave, but not the BDP. I bench tested the sensor with a reluctor wheel (from the gearbox actually) and saw a sine wave again. Documentation stated that the value of the sensor should be around 150 ohm, so I decided to change it. New sensor came in at 136 ohm. Installed it, engine started, but problem persisted.

I decided to recheck timing. I found that the locking tool for the cams can be used up side down, which I may have done before, as timing was off (Still able to turn the engine without valve interference though...). I retimed the engine, using a procedure found somewhere. I rewrote it a little for clarification:

- Have the crank (locked) in position on its mark. (tool locks in crank behind starter, if using; turn engine past mark, insert tool, turn engine back until the tool stops the crank. Marks should now line up.)
- Lock cams in position, IN LINE WITH THE SEAM IN THE HEAD. (Mind you that you can also lock the cams with the tool upside down. If so, the tool doesn't align with the seam in the head and timing will be off)
- Undo the 3 small bolts in both cam pulleys (8 mm wrench for exhaust cam, 10 mm wrench for intake cam) Ensure all all notches are lined up on the cam pulleys with the timing belt cover.
- Put the timing belt and tensioner on.
- Inner bolt on exhaust cam pulley that fixes the unit onto the camshaft should be torqued down. (This is the center bolt behind the torx 55 center cap)
- VVT unit should be turned fully counter clockwise (bolts will be on the left of the holes in the cam pulley when this is done).

If you can't achieve the last step, ie the VVT unit will not move far enough counterclockwise for the three bolts to be at their leftmost limit, then the center bolt that attaches the unit to the cam needs to be loosened as their relative positions are incorrect. Adjust it, torque it, and try again.

- Keep cams locked, pulleys at marks amd crank locked\at mark.
- Fit the center cap onto the VVT unit (T55 torx), no need to torque it yet.
- Rotate the VVT unit clockwise (spring loaded) using the cap with a T55 torx until it hits its limit.
- Lock the three outer pulley bolts.
- Torque the VVT cap.

You should now be in a position where all marks line up and the three pulley bolts on the VVT unit are on rightmost part of the holes in the toothed gear.

- Remove locking tools, rotate the engine at least 2 cycles and recheck timing.

Note: I have seen that the VVT spins a bit relative to the cams, which means the cam locking tool doesn't line up perfectly. So, check the timing based on the marks on crank and both cams relative to the timing cover. These should always be intact.

After following this procedure, I started the engine and it ran much nicer. I still have to put the subframe back as well as fasten hoses, clamps etc. Testdrive and update will follow.
Joost
Posts: 21
Joined: Sun Dec 17, 2017 6:24 am
Year and Model: 1999 S80 T6
Location: Netherlands
Been thanked: 1 time

Re: Volvo S80 T6 1999 bad start, bad idle after overhaul

Post by Joost »

Oh, another thing:

I saw a drip of ATF on the visco coupling on the right drive shaft. I first thought it was coming from the gearbox seal, but that turned out to be wrong. It was coming from the actual shaft.

I pulled it out, put the big black part in a vice, took a piece of wood and hammer, and hit the inner shaft (gearbox side) with the wood to protect the shaft. The whole inner shaft comes out now, and reveals a seal and inner bearing. Apparently, the bearing can not be ordered, but the seal is available (there are 2 versions, 42 and 47 mm I believe) Mine was part# 8636206. I ordered it, and put it in, put shaft back together, leak is gone.
bronco
Posts: 194
Joined: Sun Aug 11, 2019 7:21 pm
Year and Model: 1998 V70
Location: boston
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Re: Volvo S80 T6 1999 bad start, bad idle after overhaul

Post by bronco »

Joost wrote: Wed Oct 07, 2020 3:24 am Hi all, I try to update this thread until the solution is found. Update on the gearbox: it turns out that I mixed up the 2 thinner pipes that you can find under the oil pan, leading to the accumulators. They fit either way, somehow I mismatched them. When I restored it, the gearbox went forward and reverse again. However, I haven't been able to test it fully yet.



now that is interesting ! so it was applying pressure to the wrong accumulator ! that would be difficult to tell , what made you even notice that?
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