Volvo 850 Turbo smoking, no power

i.e., early-mid June?

You don't say how many miles are on the engine, total, or how many you've driven since early May but, omigod, six quarts of oil in three months?!? Did your mechanic do a compression test? My first hunch would be that you need rings, at a minimum.

Yup; sounds like rings.

And by the way: how can you let an engine even _get_ two quarts low in the first place?!?

cheers,

Henry

Have your mechanic check the complete pcv system for blockage. At the turbo inlet hose area there is a small plastic nipple where the 3/16" pcv hose connects. This plastic nipple has a brass insert and a smaller restricted hole inside the brass insert. The hole inside the brass insert can and will block up and can cause all of the symptoms that you describe. Once a turbo fails, it does not unfail. Sounds like the turbo is OK. BD

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Hello,

How would you recommend cleaning out the hole the brass insert? Is this like a carburetor jet, where don't want to risk enlarging it? I have compressed air and carb cleaner. What else would I want to look for in the rest of the PCV system?

Thanks,

-Eric

I had similar symptoms. One thing you don't mention is the colour of the smoke. I have an old oil-cooled turbo whereas yours is water cooled but if the smoke is blue then you're burning oil and the turbo may be toasted, if the smoke is white then you're burning coolant (likely a similar turbo failure as in the oil-cooled type) and your turbo is probably toasted. If it's thick black/grey smoke then it's your fuel mixture and you need to change your O2 sensor (Lambda Sond).

Like BD said, a broken turbo won't unbreak itself.

Also, if your O2 sensor has failed (someone recently told me the 850 has 2 of them) then the rich mixture may also lead to a plugged (or partially plugged) catalytic converter.

I had my cat completely bored out (i.e. removed) and got all my power back (plus I can hear the turbo howl now). Then I replaced the O2 sensor and my fuel economy went up and the dark smoke stopped.

To sum up: if your O2 sensor(s) fail then the fuel economy goes down and (more) smoke is produced, the particles in the smoke narrow and eventually clog the channels in the catalytic converter, and the turbo stops boosting, the needle on the guage stopping part way up.

I got this fixed last week and have been speeding and grinning-like-a-maniac ever since!

blurp

On 4 Aug 2004 07:13:53 -0700, the illustrious snipped-for-privacy@yahoo.com (Eric Goforth) favored us with the following prose:

83 240Turbo 320,000km and counting!

"In the absence of facts I will speculate wildly."

I assume that neither the Air mass meter or CMP sensor is an O2 sensor?

That's correct.

The air mass meter measures the air flowing into the engine. It's located in between the air filter box and throttle body. The CMP sensor = CaMshaft Position sensor - tells the computer which cylinder is coming up to firing position since the flywheel position sensor has no way of telling this. It's located on the back of the camshaft that doesn't have the distributor on it.

Hello,

I found the following bench test info for O2 sensors. I sounds easier than most of the tests I've seen using propane enrichment, etc.

It was at:

Testing O2 sensors on the workbench. Use a high impedence DC voltmeter as above. Clamp the sensor in a vice, or use a plier or vice-grip to hold it. Clamp your negative voltmeter lead to the case, and the positive to the output wire. Use a propane torch set to high and the inner blue flame tip to heat the fluted or perforated area of the sensor. You should see a DC voltage of at least 0.6 within 20 seconds. If not, most likely cause is open circuit internally or lead fouling. If OK so far, remove from flame. You should see a drop to under 0.1 volt within 4 seconds. If not likely silicone fouled. If still OK, heat for two full minutes and watch for drops in voltage. Sometimes, the internal connections will open up under heat. This is the same a loose wire and is a failure. If the sensor is OK at this point, and will switch from high to low quickly as you move the flame, the sensor is good. Bear in mind that good or bad is relative, with port fuel injection needing faster information than carbureted systems. ANY O2 sensor that will generate

0.9 volts or more when heated, show 0.1 volts or less within one second of flame removal, AND pass the two minute heat test is good regardless of age. When replacing a sensor, don't miss the opportunity to use the test above on the replacement. This will calibrate your evaluation skills and save you money in the future. There is almost always *no* benefit in replacing an oxygen sensor that will pass the test in the first line of this paragraph.

How hard is it to remove an O2 sensor from the exhaust system without damag> >

One thing this "test" misses is checking the heater. The other pair of wires are to heat the sensor - either to speed its response from cold, or maybe the sensor won't get hot enough to work without the heater working.

Most often they just come right out with no problem, but every now and then you get a seized on that resist all efforts to get it out. In that case the threads are so damaged that you can't reuse it. If you do take yours out with the idea to reuse it, make sure you have some anti-seize compound for the threads for reinstall.

Most of the time the computer diagnostic will let you know if a sensor is bad - often in fact it's too sensitive and condemns sensors that appear to be working fine. However, there are cases where the diagnostics will not pick up a bad sensor - I even had on my S70.

Hello,

I'm trying to find the nipple that you're talking about. The main air hose appears to flow from the air cleaner endwise into the turbo. Between the main air hose and the turbo appears to be an intermediate place.

This intermediate piece between the main air hose and the turbo has a vertical hose coming off of it. I'd estimate that this vertical part looks like it's probably a 9/16" to 3/4" in diameter. Pointing backwards towards the firewall from this vertical hose there appears to be the 3/16" hose that you're talking about.

There appears to be somtehing else that connects to this vertical hose pointing towards the front of the car. I've disconnected the hose that connects to the nipple that points toward the firewall and have tried to see inside it with a mirror-on-a-stick and a flashlight, but can't see the brass insert.

Is this the right piece? How do you safely clean it?

-Eric

Eric,

I have to remind you that my limited experience is based on the 240 so the location and ease of extraction will likely vary between the 240 and the 850.

On the 240 Turbo the O2 sensor is in an impossible place, on the underside of the exhaust manifold crowded by the turbo and several other hoses and wires. No room for a wrench to get good purchase. In order to remove it (as there was no socket that was the right size AND deep enough) we had to shear the end off of it with a long screwdriver and a hammer and then use a regular depth socket to remove the remnants.

What came out needed no testing to determine its status: It was white and caked with deposits (it looked calcified although I realize no calcium is involvoed). The slits in the tip of the sensor were almost entirely sealed up with the white chalky build-up so replacement was the correct course of action. Now had we destroyed it to remove it and then found that it was shiny and new-looking I would have been out some $$ and feeling foolish.

I believe there is a way to test the O2 sensor in situ so you don't have to go through the hassle but, again, the procedure and desired readings I have are for the 240.

Hope this helps somewhat.

blurp.

On 5 Aug 2004 16:35:37 -0700, the illustrious snipped-for-privacy@yahoo.com (Eric Goforth) favored us with the following prose:

There are several sockets specifically for oxygen sensors. They make getting the sensor out of your 240 turbo a 2 minute job, assuming you have a long enough extension.

Distibutor cap cracked?...happened to us, 850 T5.