Hello:

Just failed the AirCare (Vancouver, B.C., Canada) with my trusty 1981 245 DL wagon. WAY too high on NOx at driving speed (and high hydrocarbons at idle). Here are my 'stats':

Hydrocarbons (ppm)

- Driving: 76. (average is 27, pass is 210)

- Idle: 404. (average is 43, pass is 407) ***

Carbon Monoxide (%)

- Driving: 0.08 (average is 0.26, pass is 1.45)

- Idle: 0.46 (average is 1.80, pass is 4.57)

Oxides of Nitrogen (ppm)

- Driving: 3685.00 (average is 1018.50, pass is 2111)

BEFORE the test I poured some methyl hydrate in the gas tank, and made sure the car was warm.

AFTER failing the test, I have since changed the oil (which was very old) and filter.

Does anybody have any thoughts or suggestions on this? A bit of an intimidating prospect for me right now, and would certainly appreciate any help!

Thanks so much in advance,

Andrew Jeffrey

ajeffrey@vcn.bc.ca

Hey when is the last time you were angry about being rich?

Arent puns fun?

Anyway, hey im in Edmonton Alberta By the way, nice to see so many Canadians here.

From glancing at your stats I would take a guess and say your mixture is running too rich. If its too lean, you get lots of carbon monoxide. But, your carbon monixde is low, so the carbons have to go somewhere, and in your case they are just not being burnt or incompletely burning producing (or retaining already available) hydrocarbons, because there is not enough oxygen. Not enough oxygen means low carbon monoxide and low carbon dioxide, but again the carbon has to go or stay somewhere, and so thats why the hdrocarbons are high.

Now why would there be lots of carbon monoxide if you run lean you ask, since there is plenty of oxygen? Well I guess all the carbon dioxides are filled up already and there are a few too many loose oxygens and carbons running around (equal amounts left over now rather than 2 oxygens and 1 carbon) so it creates carbon monoxide, tons of it, and tons of carbon dioxide.

The other thing is, how old is your gas in the tank? is it any older than 3 months?

Bad fuel causes hydrocarbons, make sure there isn't crap in the tank. Even if the gas looks clean it can be bad. If you have filled up at a gas station though normally, like once a week or so, then it shoudl be ok, try a different fuel octane rating and a different gas station if all else fails.

thanks lars and dave for your suggestions -

- catalytic converter: wondering if there is there a certain volvo (or other) cat that i could pull from the junkyard if necessary?

- running too rich: super interesting, read up on this in the shop manual, and will be looking at my carb tomorrow - and probably i should check timing too it seems first

is there an additive that would help me pass the test? someone suggested that there might be too much gunk in the manifold, would this require physical cleaning, or some liquid?

thanks,

andrew

Just had similar AirCare results with our '85 245. T'was indeed the cat -guts all loose and broken. Replaced with a new aftermarket one and passed with flying colours. Even came well within California specs which are about 1/5 of ours.

A used cat is one possibility. Just make sure you can see the inside cone in one piece, not plugged with a heavy carbon deposit and nothing loose. No guarantees, but the odds are better if you try to get one off a younger, low mileage vehicle that hasn't been in an accident. Getting the old cat out may be mildly challenging as the flange nuts will likely be rusted -acetylene torch or angle grinder may be needed.

The next cheapest solution is to have the old cat cut out and a generic cat spliced in. Your local muffler shop can probably do this for under Cdn$150, just don't expect it to last forever.

A better solution is to get a "direct fit" aftermarket cat specifically designed for your car. Local muffler shops are quoting over $300 to install one. Swedish Service (Royal Oak at Imperial in Burnaby, 604-434-2535) is a reliable import shop and can fix you up right for less. If you want to DIY then you can get one through Imparts (Willingdon at Lougheed Hwy in Burnaby, 604-293-1511) for under $200. NAPA and Lordco would be other good sources. If you get Volvo to install an OEM cat then you're probably looking at between $500 and $1000.

Make sure you give the car a few good highway runs before retesting to burn off and blow out any deposits. New plugs and quality gas also wouldn't hurt. Arrive at the testing station with a fully warmed engine and try to pick a less busy time so you won't have to sit around idling too much. I recently spent some time at AirCare's Research Centre. Despite rumours you may have heard, it shouldn't matter which station you go to or at what time of day. All instruments are standardized to a common reference at the start of each day as well as being regularly re-calibrated throughout the day. Stations are cross-checked daily.

I think fuel injector cleaner or carb treatment or something would work.

Maybe spray it right into the manifold through somewhere, spray the throttle body and then when you have it all back together run car.

Only problem is you might loosen up a lot of s&*t adn put it into the combustion chamber, but I doubt there can be too much crud in there.

I haven't had a carb car so I don't know if you can get treatments but I am sure FI cleaner would work and also help flush out the tight spaces in the carb that may be clogged causing screwy mixture etc.

How does the car smell? does it stink out the exhaust? If it stinks like crappy sour eggs or something you got bad gas, but your probably filling it up ever week and driving it, see I am used to Porsche owners, the cars never get driven, they are peices of unreliable crap and people let em sit cause they aren't fixable, then sell it to some sucker (hint: me) and turn into dust and the gas goes bad. Volvos are driven though, so its unlikely you have bad gas, but just incase.

Just dealt with a similiar problem with my friends 87 dl. Here in NJ

he was failing for HC just over the limit. CO would pass and the

NOX was about twice what was allowed. Barring anything not correct like

your timing and the state of tune the only thing left is the catalytic

converter. We eliminated all the other stuff like tuning it up and any

vacuum leaks and when he still failed we bought a cat and put it on.

The car passed with flying colors. And, its a 220k mi car.

Hope this help you.

Dave 82 242ti