94' Volvo 855T P0131 after a new O2

Post by **abscate** » 08 Jan 2019, 03:37

What do the Finnish think?

Sommerfeldt · Post by **Sommerfeldt** » 08 Jan 2019, 06:24

They flog themselves in saunas. Which is generally a better idea than talking to either a Norwegian or a Swede.

- S

henrysin44 · Post by **henrysin44** » 09 Jan 2019, 01:43

Sommerfeldt wrote: 08 Jan 2019, 02:42 Yes, it is worth looking into.
If your V70 ECT is telling the ECU 300 ohm, the ECU thinks the engine is at 80 degrees, even though the ECT is saying it's at 40.
They're like a Swede and Norwegian talking to eachother. The Norwegian says something is "rolig". The Swede thinks something's funny, but the Norwegian is saying something's calm.

- S

true true close but not close enough, I'm going to stop by the scrapyard tomorrow and pull an 850 thermostat housing and see if it has any effect, also going to check the PCV hoses while the manifold is off maybe theyre cracked or disconnected. But if this doesn't do it I'm at a loss for ideas. But if burning oil can ruin an O2 sensor then I have more of an idea.

henrysin44 · Post by **henrysin44** » 09 Jan 2019, 02:16

Honestly this problem is starting to drive me nuts, could I really just need a new O2?

A little run down:
-Turbo has an internal oil leak? (oil in the intake manifold & intercooler).
-Runs rough when not at operating temp (1090RPM idle, rough shifts, bad MPG, sluggish)
-very quick misfire feeling under light throttle every now an then (like a blip)
-P0131
-gas and oil smell
-20-24 mpg

Post by **misha** » 09 Jan 2019, 02:22

henrysin44 wrote: 09 Jan 2019, 01:43 ...But if burning oil can ruin an O2 sensor then I have more of an idea.

Yes it can....lifetime for a brand new o2 sensor when engine is burning oil is about what you got...around 10k miles.

On the other side...when engine is burning oil,there must be more blowby than normal.That blowbuy can fool front o2 sensor that engine is running lean,because of extra oxygen that wasn't metered by MAF....BUT sensed by front o2.
When ecu gets lean condition report from various sensors it opens injectors longer,which results in rich running condition.

henrysin44 · Post by **henrysin44** » 09 Jan 2019, 09:10

misha wrote: 09 Jan 2019, 02:22
henrysin44 wrote: 09 Jan 2019, 01:43 ...But if burning oil can ruin an O2 sensor then I have more of an idea.
Yes it can....lifetime for a brand new o2 sensor when engine is burning oil is about what you got...around 10k miles.

On the other side...when engine is burning oil,there must be more blowby than normal.That blowbuy can fool front o2 sensor that engine is running lean,because of extra oxygen that wasn't metered by MAF....BUT sensed by front o2.
When ecu gets lean condition report from various sensors it opens injectors longer,which results in rich running condition.

Ive done a compression & leak down, all checked out great, i do have a horrific amount of oil in the intercooler piping and inside the intake manifold....could the turbocharger be causing that by leaking internally?

Post by **misha** » 09 Jan 2019, 09:30

If turbo is shot and leaks oil internally...that oil can foul o2 sensor....and kill it pretty soon.

henrysin44 · Post by **henrysin44** » 09 Jan 2019, 19:38

misha wrote: 09 Jan 2019, 09:30 If turbo is shot and leaks oil internally...that oil can foul o2 sensor....and kill it pretty soon.

FCP was having a sale so got an O2 sensor cheap, if it clears the code then I'll rebuild the turbo, its got shaft play anyway. I got it last summer off a junk car due to my 15G leaking internally so I'm unsure if the build up in the intake system is from the current one or not, I doubt it though because of how much I drive daily.

I'm still going to keep the old O2 sensor and see if a gasoline soak might get it working.

henrysin44 · Post by **henrysin44** » 13 Jan 2019, 18:15

Well I've had the new O2 sensor in for a few days and so far no problems or codes! Guess oil killed the 10K O2 sensor, I've had it sitting in denatured alcohol for 2 days and the alcohol has turned black.

Post by **misha** » 14 Jan 2019, 02:51

It turned black because of black soot and carbon from running rich condition you had.

O2 sensor can be cleaned in ultrasonic bath...BUT only once!