'88 240 DL Won't Pass SMOG

Swede Speed · Post by **Swede Speed** » 21 Aug 2005, 02:05

Hey,

I'm new here and this is my first Volvo. I recently bought a 1988 240 DL. The car is in showroom condition and has only 76k miles on it, but it wont pass smog. The person I bought it from forgot to get it checked, b/c after all it is the seller's responsibility. Long story short, I took it upon myself to get it checked, and it wont pass. What could the problem be? Could a sensor possibly be broken? How would I be able to tell/get a new one if necessary? Thanks so much for your help!

-Brian

Kmaniac in California USA · Post by **Kmaniac in California USA** » 21 Aug 2005, 08:47

Brian:

I would like to help you with your problem, but I need more information. As a California resident, I am familiar with Smog Check II and the new treadmill test.

What parts of the test did your car fail? You have your basic functionality tests (visial inspections and adjustments) and your tailpipe test (gas emissions). Look at your form and list everything that failed, then I can point you in the right direction.

Swede Speed · Post by **Swede Speed** » 21 Aug 2005, 14:56

Chris,

I very much appreciate your help. The 240 was taken to my local Smog Pros here in South Pasadena. Here's what the tests say:

"Visual Inspection.. (Pass)
Functional Check.. (Pass)
Emissions Test.. (Fail)"

So it looks like the 02 sensor passed and the wiring to sensors and all the other jazz passed, well.

Okay, here are the ASM Emission Test Results:

HC (PPM) - At 15mph it measured 36, the max is 116 - PASS
HC (PPM) - At 25pmh it measured 29, the max is 91 - PASS

CO (%) - At 15mph it measured .05, the max is .74 - PASS
CO (%) - At 25mph it measured .04, the max is .62 - PASS

NO (PPM) - At 15mph it measured 1721, the max is 791 - FAIL
NO (PPM) - At 25mph it measured 1732, the max is 730 - FAIL

Does that make sense? Is there anything that I left out? Thanks again for all of your help!

-Brian

Kmaniac in California USA · Post by **Kmaniac in California USA** » 21 Aug 2005, 16:18

Brian:

Your 240 is gorgeous!

Your smog test passed everything except for NO, aka Oxides of Nitrogen or NOx. High NOx values are indicative of high combustion chamber temperatures during combustion. The emission control device installed on cars to lower NOx is the Exhaust Gas Recirculator or EGR. High NOx values indicate that your EGR system is not working correctly. Your problem could be either an EGR valve that is not functional, vacuum lines to the EGR valve which are leaking or disconnected, or exhaust gas ports to and from the valve that are plugged. Check the functionality in that order.

Now there is one thing I need to mention. My knowledge of Volvo's is limited to my 1986 740 GLE. I have an non-turbo 2.3 Liter four that appears not to have an EGR system. I seem to recall other posts to this forum where I heard that these cars may not have come with EGR's. I don't know for sure whether your 1988 240 came with an EGR system or not. If it does not have an EGR system, you may have to consult with a smog referee for a variance. If other people out there can tell us whether or not a 1988 240 came with an EGR system, please let us know.

One of my thirteen cars is a 1980 Dodge (Mitsubishi-built) D-50 pick-up. It got it's first treadmill smog test last month. This vehicle failed due to high NOx. I found that the vacuum lines to my EGR had deteriorated causing the EGR not to function. After new vacuum lines were installed, it passed. My measured NOx was 1379. The maximun allowable for this vehicle was 1383. So I just bearly passed.

Kmaniac in California USA · Post by **Kmaniac in California USA** » 21 Aug 2005, 22:27

Brian:

I searched the forum for other posts regarding EGR systems and high NOx. Search the forum for entries by "rlumbard1". He had the same problem with a 1986 240 that did not have an EGR system. There is a reply to his post that is informative.

If you haven't done so already, I would suggest a full tune up. Replace the spark plugs, wires, distributor cap and rotor. Make sure all the timing and idle adjustments are proper. Also, too, check for vacuum leaks. Deteriorated vacuum hoses will draw in extra air (unmetered), causing the mixture to run lean and hot. Also check your vacuum reservoir tank for cracks and leaks, too. Then, before you take it in for the test, fill the tank with the best fuel possible (premium) and take the car for a long, high speed drive to clean it out. Say, a spin on Foothill Freeway out to San Berdu and back. Then make sure the car is good and warm just before the retest.

Good luck with this and let us know what happens.

Swede Speed · Post by **Swede Speed** » 22 Aug 2005, 00:31

Thank you so much for all of your help. I will for sure take it in for a full tune-up and make sure it's running hot when I take it in for smog. I'll let you know how it goes. Hopefully this will help people with the same problem in the future.

Thanks again,
Brian

dpauto.com · Post by **dpauto.com** » 24 Aug 2005, 00:09

Swede Speed,

Kmaniac in California is definitely right about high NOx emission when EGR is not functioning.

However, your 1988 should not have an EGR valve, not until 1989.

Your CO and HC were ok. Your NOx wasn't. I'll put my money on the bet and say it's your Catalytic Converter. A muffler shop usually charge $120-$140 for an aftermarket cat. But keep in mind, an aftermarket cat's life span is around 2-3 years.

In few cases I have seen bad air mass meter and clogged injectors (make engine runs too lean) can cause high NOx. But then your CO appeared normal. Air mass meter and injectors are a lot more than an aftermarket CAT.

I was a licensed smog tech for 11 years at the Volvo Dealer

Regards,
Dave

Swede Speed · Post by **Swede Speed** » 24 Aug 2005, 02:17

Thanks a ton for your input. I'll let you all know next Tuesday when I take it in.

Swede Speed · Post by **Swede Speed** » 30 Aug 2005, 15:02

Okay, after the full tune-up, my NOx levels are:

15mph - 539, max is 791
25mph - 302, max is 730

PASS!!!

All it needed was a tune-up. It runs great and I couldn't be happier. Thanks for all of your help everyone.

GoForVolvo · Post by **GoForVolvo** » 16 Oct 2006, 23:36

i have an '87 240dl... failed only the NOx portion of the california smog check a couple weeks ago... failed miserably.

15mph - max 785 - measured 1730
25mph - max 724 - measured 959

after a major tune-up and a replacement of a burned out oxygen sensor, she passed EASILY.

15mph - max 782 - measured 116
25mph - max 724 - measured 59!!!

i struggled to pass two years ago, too... and after $550 it just barely squeaked by (i'm not sure the guy didn't just give up and cheat the system). the difference - this time i had it repaired at a VOLVO GARAGE. lars the mechanic (at victoria motors in culver city/marina del rey) knows what he is doing. wish i knew about him last time i failed the smog check.

thanks for the help! i very much appreciated the previous posts about failing a smog check and the possible causes...