1984 Volvo 244 DL 2.3 L failed emission test
 

Hello,

I live in California and bought the car last year. 126000 miles. Smog test failed. The NO number (1200) was higher than maximum (1000).

1) One smog station told that, the car has the wrong catalytic converter part. I went under the car, found the converter, but can't find the number. Where is the number?

2) What could cause the NO number to be high? How can I fix it? I changed oil, and filled the tank with 91 octane gas. It failed the test again.

Thanks for any advice.

Cats rarely have a number, any way I'd question the "wrong cat" diagnosis unless the car is a EGR car with no EGR cat? Many things can cause high NOx, lean fuel mixture, vacuum leaks, overheating, carbon buildup, etc. Hard to give definite advice on this one.

pretty sure there was no EGR on a 1984 California 240... there wasn't one on our 87 either, but there was on the 91 and 92, and later cal models.

change the O2 sensor, and bring the car in as hot as you can get it for the smog test, leave it running til they start the test.... if that doesn't fix it, you probably need a new catalyst.

re: wrong cat, cheap aftermarket cats are known to barely last a year, so they've been banned in california, you have to install a CARB approved cat which cost about twice as much, but will last as long as the original (20+ years, 250000 miles typical as long as the car hasn't been run too rich for a long time).

Thanks for your replies.

After taking the car to a near local Volvo repair shop, I was told that one of the reasons for high NOx is that, Mass Air Flow sensor is not working and needs to be replaced. Baed on my observation, temperature gauge is always closer to the "Cold" mark, no matter how long I drive the car. Also mechanic said the O2 sensor is working fine. He also said the Cat has been replaced with an after market part in the recent past (two years).

Does the diagnosis (changing MAF) makes sense?
Where I can buy a reliable MAF and Cat for my Volvo?

Thanks.

smog
 

damn i didn't even know you had to get emissions for that age car in cali in Georgia we dont after i think 95 now or something i know most cars would not pass at all.

I've never seen or heard of a MAFs to cause this, but can't say for sure, can say it's unlikely. You can buy a cat on line, or any muffler shop can help you, plenty on ebay around a $100...

Did the readings improve any the second time? If the car is running too cold, not reaching operating temp-- that will affect the emissions--check the actual engine temperature with a reliable thermometer!

um, CARB approved cats were more like $200 last I looked, and noone legit will ship a non-carb cat to California. The cheap cats don't last a year, hence why CARB started their approval program. NAPA Auto stores can order Magnaflow for a early 240 like yours, either a direct fit (bolt on), or a universal fit (muffler shop will need to weld it on, likely with some new piping).