1996 850 Turbo, Rough idle, new PCV didn't fix it...

futureboycolin · Post by **futureboycolin** » 28 Sep 2013, 20:08

Hey y'all! Longtime no see.

So my '96 850 turbo was shaking and rattling all over the place, misfiring, had low power in 1st gear, and a horribly rough idle.

First of all, I just replaced the PCV with the kit from FCPeuro (all Volvo OEM parts), and also replaced the lower right motor mount, upper torque rod bushing and firewall torque bushing. I cleaned out the PTC, but did not mess with the EGR or the throttle body cleaning.

The engine vibration is mostly gone once I'm in 2nd gear, but in 1st and idle, it's still shaking and chugging, and seems like it's on the verge of stalling. In idle, the engine is rocking quite a bit, and it sounds like there's a misfire on one of the cylinders...it's going GLUG GLUG GLUG, and the exhaust is glugging, not humming and whirring like it used to. I don't think it's a vacuum leak (although one end of the hose that came with the kit was too big to stay on the PTC nipple, which was infuriating as there aren't any clamps small enough to keep it on! I had to jerry rig a new nipple with a vacuum line connector). Could it be the intake manifold gasket (I didn't use any permatex or silicon or anything on the gasket)? I'm sure it's an air leak somewhere, but I'm not sure where else to look. I know everything was reconnected correctly...I think. I've also noticed that I'm actually getting LESS boost than before I did the PCV, not only that, the old PCV system wasn't even that dirty or clogged. The plug on cylinder #1 was also very sooty last time I checked them.

My plan is to replace the dipstick tube with the updated double o-ring part, put in new NGK copper plugs, a new filler cap gasket, run some Lucas injector cleaner, seafoam the POS, check all the vacuum lines and hose connections, and I guess replace the 2 hydraulic engine mounts and the transmission torque mount while I'm at it. Any sage advice??

engine noise -
exhaust noise -

Post by **MoVolvos** » 28 Sep 2013, 20:27

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Was this problem the direct result from/after the PCV work? Perhaps the link will help if you think it is a vacuum leak.

How To Find A Vacuum Leak - EricTheCarGuy

Blessings,

BKM

**

futureboycolin · Post by **futureboycolin** » 28 Sep 2013, 20:41

No, I was hoping that the new PCV would resolve any blow-by issues that were fouling the cat, o2 sensors, causing misfires or fouling spark plugs. I will check the plugs tomorrow and see if they're clean, and read the codes to see if there's any new info.

Also planning on cleaning the o2 sensors to see if that may be the cause of the engine running rich?

Post by **MoVolvos** » 28 Sep 2013, 21:09

futureboycolin wrote:No, I was hoping that the new PCV would resolve any blow-by issues that were fouling the cat, o2 sensors, causing misfires or fouling spark plugs. I will check the plugs tomorrow and see if they're clean, and read the codes to see if there's any new info.

Also planning on cleaning the o2 sensors to see if that may be the cause of the engine running rich?

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My experience with my 98 S70 T5 high mileage car is that motor oil makes a critical difference as in this recent post. Don't know if it was blow by or turbo but the problem may be completely solved or greatly reduced.

https://www.matthewsvolvosite.com/forums ... =1&t=59045

As for the current problem you have check for vacuum leaks. I bent the Intake gasket when checking for fit with the Manifold.

Blessings,

BKM

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futureboycolin · Post by **futureboycolin** » 29 Sep 2013, 11:50

Any other advice?

futureboycolin · Post by **futureboycolin** » 29 Sep 2013, 12:52

Just looked for a vacuum leak with some Brakleen, and it looks like the intake manifold gasket isn't tight, but the idle didn't really change all that much. I did notice some bubbling of the liquid that was sitting on top of the manifold where it meets the block, near cylinders #1 and #2. Should you still be able to see the edge of the gasket peeking out?? Anyone know the torque specs on those bolts? I didn't use my torque wrench when reinstalling the manifold. I'll upload a video of the engine idle and exhaust sound shortly.

EDIT: Found the torque specs...14 ft/lbs. Guess I'll need to check that later today.

Post by **mikealder** » 29 Sep 2013, 13:38

If your inlet manifold isn't sat correctly I would take it off and start again but take greater care when refitting the support bracket the connects between the underside of the inlet manifold and the forward face of the engine block.

Leave the support bracket loose where it bolts to the engine, get the manifold secured in to position and attach the support bracket to the manifold tightly then finally tighten the support bracket bolts to the engine front face, not ideal as you are working blind but a mirror and torch will resolve that issue.

If you secure the bracket too high (it is slotted where it connects to the engine front face) the inlet manifold will never seat correctly and cause an air leak - Mike

Post by **MoVolvos** » 30 Sep 2013, 00:00

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You'll need to remove and recheck that gasket to make sure it is still OK.

Per "mikealder" tighten the 2 Bracket bolts under the Manifold slowly alternating between the 2 bolts so you do not bind or put pressure on the Manifold.

Blessings,

BKM

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futureboycolin · Post by **futureboycolin** » 30 Sep 2013, 22:44

Well don't I have egg on my face. Turns out I forgot to tighten the lower manifold bolt down below cylinder #1. I went back through all my work checking everything, and torqued all bolts to spec. Everything is tight and shipshape. The boost is back. BUT...

I pulled my plugs, and plug #1 is fouled with oil and carbon deposits again. I'm also getting a backfire/popcorn noise when I accelerate in 1st gear, and I'm sure it's cylinder #1 misfiring. Don't know if anyone listened to those videos I posted in the OP, but that gluglugluglug noise is still coming from the rear of the engine...exhaust leak?? The engine is still shaking like crazy when I decelerate into 1st, and when I idle, and my trip computer is telling me I'm getting an abysmal 8.9mpg average. WTF??

Post by **MoVolvos** » 30 Sep 2013, 23:59

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Do you smell unburned fuel in the exhaust?

Have you check for codes?

Do you have spark to the #1 plug?

Pull the plug wires one at a time and see if the idle changes

Do a compression check on the #1 cylinder

Do the vacuum leak test again.

Test MAF

Check the O2 sensor

Change to a new set of Bosch copper plugs.

Change the oil to a 5W-40.

The Videos: Sounds like that of an oil deprived or poorly lubricated engine besides not running on all cylinders.

Blessings,

BKM

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