Failed Ontario emission,high HC/CO,low NO.O2 sensor? which brand best?90 740 GL

B230F Regina 165000 km=100 000 miles. Already Ran a bottle of US
Tehron in fuel tank prior to test.Used 91 octane shell+94 Octane
Sunoco(with ethanol ?10 %)
ASM 2525 failed. Curb Idle passed
HC ppm 92 FAIL( limit 69)2 yr ago was 40 Curb: 113(limit 200)PASS
CO% 0.77 FAIL(limit 0.38) 2 yr ago 0.43(limit then)Curb:0.98(limit
1.00)PASS
NO ppm 26 PASS(limit 777) 2 yr ago 16 Curb N/A

Overall:fail

From looking at the FAQ,the stock 13 yr old oxygen sensor may be
suspect.What Brand should I get ,Fcgroton sells Walker direct
fit,,while foreigncarparts at Groton sells NTK by NGK o2 sensors.Which
one is better?I guess a universal fit Bosch would not fit a Regina fi?

Talked to dealerVolvo Villa.They dont do "diagnostic tests" or
emission tests.
Talked to independent mechanic friend,told me to run a bottle of CRC
Guaranteed to Pass Emission cleaner and have it retested at half price
at original test site.If it fails again,then contact him.

Any advice.Does it look like the 13 yrs old o2 sensor?
Tom

 

Imagine - a Volvo dealer that doesn't do "diagnostic tests"!!!! Ha ha
ha, really builds confidence doesn't it?

To me your emission numbers look like a clean running, properly tuned
car without a catalytic convertor. My guess is you'll need to change
the convertor to pass, but honestly there's no substitute for a sharp,
experienced mechanic who has the car. He should be able to tell the
state of the convertor by seeing how hot it is after normal running.

 

First off, I'd use the lowest octane gas you can find without ANY additives.
Injector cleaner alone will make it rise fast on a test.

Hydrocarbons and CO are the result of bad burning and while the Cat does
help a lot, it's not a miracle cure. 87 Octane gas has a higher energy per
volume, which means if they run the test on a dyno(engine under stress),
the car will be working a BIT less hard than with 94. Especially don't
put additives and ethanol mixed gas in.

The low NOx is a sign that the cat is probably in good shape. When mine
failed, it jumped to over 1000. New cat and it dropped to ~50.

You're not THAT much over, so it's more of a running rich/dirty problem, IMO.

Recommendation:
87 Octane gas if run on a dyno.

Basic tuneup - all cars can use a new set of plugs, air filter,
and oil change. Less air flow from a dirty filter means the
car will run rich. Properly running, it will emit a LOT more
NO as a result, but you are way under the limit there. You can
afford to run with a leaner ratio(more air).

On plugs, I recommend a plain high-quality plug. I'm not a fan
of the Platinum or splitfire or simmilar types. The ones with
a big, fat center piece and two outside ones(forget the technical
terms right now) are that I use. Holes or whatnot in the components
means it wears out MUCH faster. Two, though, is nice. I've seen
ones with four, but that seems overkill.

O2 sensor. If the sensor is $$$, and not the older screw-in giant
spark-plug type, do the other things first and test. If it is
a normal easy to install/buy type, replace it. Mine was $30 last time.

Run the car at highway speed for 20 minutes or so before the test.
You want the engine as warm and optimal as possible, so that
when it starts up, it doesn't run rich for the first few miles.

 

So 87 Octane is the way to go?/

I will post back later if it's the cat(Mike Froebel) or o2
sensor(everybody else cos of low No #s).First off,tune up already done
prior to test though I did re-oiled or maybe over-oiled a cleaned K&N
air .filter.

Just wonders whether to use a new paper filter instead?
Thanks for your advice.

 

Absolutely. The H&N actually restrict flow, believe it or not, in most
designs, especially if re-oiled. This might account for some of it,
if the air flow isn't as "clean" as you'd like.

 

Changed oxygen sensor.Expensive.But passed.
HC now at upper limit allowed =69
co down to .32
NO increased to 191 but way below limit of 777
Thanks to everybody who responded.
Tom