850r failing emissions miserably (HC and CO) Topic is solved

[JayPea44]

Hey all - I have a newly purchased 850r sedan that is failing its emissions tests pretty terribly here in Colorado. It's failing on high (very) CO and HC.

HC = 2.9 GPM (limit is 0.8 )
CO = 88.7 GPM (!!!!!) (limit is 15.0)

CO2 and NOx are fine within limits. The gas cap is fine etc. I've put my (cheap) OBD2 scanner on there and there are no problem codes. The car runs fine, doesn't hunt when idling, and doesn't bog down under accel, no smoke or smell from the back (apart from a little white smoke as it's so cold right now).

I'm fairly aware that high HC is an ignition problem and could be lean or rich, and then high CO is too much fuel and not enough air (rich AF mix)?

The car has had a new motor 2 years ago with plugs and wires etc replaced then, and after the motor replacement, it passed its last emissions with flying colors, well below limits.

I've done extensive searches and on the information from them I've decided, just to be safe, to do a full stage 0 tune-up kit (plus, wire, dis cap and rotor, oil change, and air filter) as well as replace the PCV system as I do have smoke from the dipstick and filler cap. Could this be the problem?

I thought it might be an o2 or MAF sensor but I'm not getting codes. My other thoughts are to dump some techron in the tank and add some 91 octane (pretty sure the last owner put 85 in there...) and run it until empty then fill with 91 again and techron and get it rested once I've done the PCV and Stage 0. I did think maybe CAT too, but the NOx and CO2 are fine, and again, no codes.

Just looking for some advice and thoughts from some more knowledgeable guys on this, as I'm a little stumped about how it went from no problems on the last test to being so drastically high this time.

Cheers.

[scot850]

I always recommend running the turbos on Premium gas (91 and up). You are likely to burn a valve on regular gas.

Worth running a tank of premium gas and injector cleaner and see if that helps. Has the car been sitting for any time?

A stage 0 might be worth it and check if the flame trap is clean if it is still fitted. If it is fitted and blocked it will cause weird running. Remove it and either clean it out or just leave it out and see if thing improve.

Have you tried the glove test on the oil filler hole to see if you are getting positive crank pressure?

Neil.

[JayPea44]

Ok thanks, I think the next step is going to be fill it with Premium and Techron to give it a clean up. I'm sure the 85 isn't helping.

I think it has been sitting a little, the previous owner said he hasn't been using it as much, but I don't think it's been sitting without running completely for an extended period. Didn't do the glove test, but I am getting smoke out of the dipstick and filler cap with the cap off and stick out. I'll do the glove test, is that just simply placing a glove around the cap and seeing if it's sucked in?

[WhatAmIDoing]

Yes, just stretch a glove over the oil fill and see if she sucks or blows. Obviously if it becomes a balloon, then the pcv should be fully serviced.

Do they really require such an antique at this point to pass emissions? Most states I know exempt anything over 25years old.

[Clemens]

Wasn't a high HC a sign of badly worn rings? But maybe a PCV problem would cause high HC as well.
Oh, and check if you have a vacum leak. A GM 4 banger I owned had a high CO because of a tiny leak in the intake manifold gasket.

[JayPea44]

Wasn't a high HC a sign of badly worn rings? But maybe a PCV problem would cause high HC as well.
Oh, and check if you have a vacum leak. A GM 4 banger I owned had a high CO because of a tiny leak in the intake manifold gasket.

Ugh I hope not, it doesn't have any blue smoke out the tailpipe, that I've noticed, I'll let her run for a while and see. Could be a vacuum leak but it doesn't hunt or anything. I'll check the lines.

Another note, that may be of interest, it does seem a little down on power, the turbo doesn't boost as high as it should, only gets to about a 1/3 into the white when I give it a boot full.

[abscate]

You are running rich as a pig with that HC. Check your fuel trims , both short and long term

[JayPea44]

You are running rich as a pig with that HC. Check your fuel trims , both short and long term

Hmmm ok. Should I reset them by disconnecting the battery? I'm not entirely sure how to check them. Sorry, bit of a noob on these older Volvos.

[JayPea44]

My OBD2 reader has live data and says it can read Fuel trim. I'll look into that, thanks.

[matthew1]

Sounds like a vacuum leak. What part of Denver are you in?