97 850 has high NO fail CA smog by 100 over max

sinclair · Post by **sinclair** » 15 Mar 2012, 15:59

I just fail a smog check in California, my 97 850 has about 300,000 miles on it. It runs great with no check engine light. I did get a code a few moths ago for evap system. Will that effect NO levels? My levels at 15mph where 506 the max is 424, After decarbonizing it went down to 496, in addition two years ago at my last smog my NO levels were around 200. Cat was replaced a few years ago. Any suggestions, should i decarbonize again? Is it bad 02 sensors, one or both, or should I try something else?

Billc1015 · Post by **Billc1015** » 16 Mar 2012, 13:07

High NOx is caused by high combustion chamber temperatures. I would check your EGR system first. The EGRs main purpose is to reduce NOx by diverting a small amout of exhaust gasses back into the combustion chamber. Since the exhaust gasses were already burned, they cannot be re-burned and it will bring down the temperature.

sinclair · Post by **sinclair** » 16 Mar 2012, 15:19

My 850 doesn't have an egr valve. Any other ideas?

Billc1015 · Post by **Billc1015** » 16 Mar 2012, 16:14

Check your thermostat and cooling fan opperation. Also, did you notice if they put a fan in front of the car when testing it?

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sit22II · Post by **sit22II** » 16 Mar 2012, 19:34

running lean ? any vacuum leaks?

Post by **MoVolvos** » 16 Mar 2012, 21:18

300,000 miles!

Use this if you can find it locally as shipping is high - One bottle for one tank with Chevron Super Unleaded
http://www.paragon-products.com/product ... co-503.htm

Independent Volvo Service - $10 Dollars if you can stop by
http://www.yelp.com/biz/independent-vol ... lnut-creek

Change to this oil 15-40W with the 503 and drive for one tank. Smog afterwards with another bottle of 503 along with Chevron Super Unleaded.
http://www.paragon-products.com/Swepco_ ... /sw306.htm

This a simple way to figure out if it is your engine or you'll have to start doing some detailed diagnostics for a car that age.

Independent can be very helpful give them a call as they also carry the motor oil although I do not know if it is the 15-40W. I buy my mine by the case of 24 Qts.

Blessings,

BKM
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sinclair · Post by **sinclair** » 17 Mar 2012, 01:04

Bill,

I don't remember them having a fan during the test.
The temp gauge is always a little above center, which seems a little high. I will check thermastat.

sit22II,

I dont know of any vac leaks. I just got a P0442 for the evap system, there might be a leak there. I don't know if that would effect the NO

BKM,

I would love to take my car to independent but I live about 8hr away.

I have done two tanks of sea foam, along with decarbonizing twice. oh, and I use 20/50.

I will try your stuff.

Post by **MoVolvos** » 17 Mar 2012, 01:19

sinclair wrote:Bill,

I don't remember them having a fan during the test.
The temp gauge is always a little above center, which seems a little high. I will check thermastat.

sit22II,

I dont know of any vac leaks. I just got a P0442 for the evap system, there might be a leak there. I don't know if that would effect the NO

BKM,

I would love to take my car to independent but I live about 8hr away.

I have done two tanks of sea foam, along with decarbonizing twice. oh, and I use 20/50.

I will try your stuff.

Check your local Porsche, Ferrari or Mercedes high performance shop to see if anyone carries it.

Andial is familiar with the Product
http://www.andial.com/

For the P0442 this may apply to your car

Blessings,

BKM
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sinclair · Post by **sinclair** » 17 Mar 2012, 14:14

any idea where the charcoal canistar is located on my 850?

btw thanks, that shop is the next city over. I'll try them monday.

Billc1015 · Post by **Billc1015** » 17 Mar 2012, 19:36

If its in the same place as my 94 850, it will be behind the bumper on the driver's side by the wheel well.

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