'93 240 failed emission test in Ontario

Got 83 on HC (limit is 66), got .40 on CO (limit is .37) and got 903 on NO (limit is 505).

Plugs were changed, air filter was changed and oil (Mobil 1) was changed prior to test. I checked the thermostat in the air box and is working fine.

Car is ONLY driven in city and has 167,000KM (~ 100,000 miles).

Do you have any suggestions? I've been thinking about replacing the catalytic converter with originalVolvo part.

Thanks.

Reply to
NoOne
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First I would check all of the ignition components. Assuming that is all well, I would put in a new oxygen sensor using a direct fit type, not the universal sensors which require splicing wires. Bosch and other suppliers offer direct plug in replacements. If you 240 still has it's factory sensor there is a good chance that it is responding poorly.

Before replacing the cat I would get a before and after emissions probe done. That will tell the story on cat. effectiveness.

Volvo original cats are very expensive. I replaced the one on our '93 with a Bosal aftermarket unit at a fraction of the cost of a Volvo unit with good results and it has passed California smog testing.

Reply to
John Horner

I forgot to write that such high readings only happen during driving test. At idle, I'm passing with flying colors! At idle, HC is 45 (limit is 200) and the CO is 0.02 (limit is 1.00).

thanks

Reply to
NoOne

It should run cleaner than that even with no cat at all, something is wrong. If it's only been driven around town, it may have buildup on the valves, could also be dirty injectors. Try dumping a bottle of Techron in the tank, then take it out on the highway and thrash it a bit to burn out carbon deposits.

Reply to
James Sweet

I'll do the Techron, but would you also recommend changing the cat? Volvo dealer told me last week that it was $383 (CAD) + tax for the part. I'll do it myself.

Thanks for the reply.

Reply to
NoOne

The cat in my mom's 240 crumbled internally years ago and has been hollow ever since, it still passes the emissions test easily. Unless the cat is plugged or crumbled, there's no sense in replacing it.

Reply to
James Sweet

My concern is that the high emissions are across the board. Normally the things that make CO go up make NOx go down and so on.

My knowledge and experience are not enough to base a decision on.

Mike

Reply to
Michael Pardee

That is why I suspect the Oxygen sensor being slow to respond. It can give you rapidly alternating rich and lean conditions which makes all the numbers go up. The emissions sniffer does an averaging function.

John

Reply to
John Horner

I hadn't thought of that. Some O2 sensors can get mighty bad without the "check engine" light coming on. I think Volvos are among the least critical of O2 function. At any rate, the sensor is undoubtedly a ripe old age by now if it is the original and replacement would be a good start. Bosch replacements have a bad reputation; OEM through a discount reseller would be a safer choice.

Mike

Reply to
Michael Pardee

The OEM sensor *is* Bosch, I hadn't heard of the bad reputation, can you elaborate more on that?

Reply to
James Sweet

No direct experience myself, but a few of the experienced regulars in the alt.autos.honda forum warn against Bosch O2 sensors (the universal replacements). The response speed initially is supposed to be substandard and the useful life barely two years (according to one source.) The same source is also a proponent of replacing O2 sensors every ten years, especially if throttle responsiveness or fuel economy is dropping off. I have no opinion yet, but I'm keeping my eyes open.

Aftermarket parts and fluids is a touchy matter among Honda/Acura folks. Power steering fluid and transmission fluid (manual and automatic) are proprietary to Honda; use of the wrong PS fluid destroys the PS seals quickly. Aftermarket ignition parts as well as starters and alternators are often so flimsy compared to OEM that many Honda die-hards accept nothing else. (I've experienced bad aftermarket ignition parts myself.)

Mike

Reply to
Michael Pardee

Thanks to all for the replies. I'll keep you up to date, but it will take some time. I went to Canadian Tire and bought a bootle to clean the injectors. After I empty the gas tank, I'll do another treatment, this time with a liquid supposed to clean injectors, valves, etc.

After I'm done, I'll try the test again and will come back to provide you the results. But I must use two gas tanks... Give me ~ 2-3 weeks...

Reply to
NoOne

Be sure to run a tank through it after you use the treatment. That stuff will skew the results (meaning fail it) for sure. And, (in case you didn't know) you will get best results from the cleaner if you do many stops and starts rather than one 400 mile road trip. It seems the thermal cycles when the motor heats up and cools helps break loose the crud.

Reply to
clay

Didn't know that. Thanks for the tip.

Reply to
NoOne

I've installed Bosch replacement O2 sensors on several cars with no issues. The big deal is to make sure and get a direct fit one, not the "universal" splice in variety.

NGK and NTK sensors are also good brands. Volvo originals are generally high priced.

John

Reply to
John Horner

Sounds good to me.

Mike

Reply to
Michael Pardee

Where can one get NGK O2 sensor? Muffler shops?

Thanks.

Reply to
NoOne

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