2003 M3 failed smog test

Hi

As the subject, my 2003 M3 failed the smog test.

The result for 15/25 mph failed in the HC(PPM) category.
Max is 51 for 15 mph and 35 for 25 mph, mine was 85 and 88.
This is much more than the limit.

I just did inspection 2 about 5 months ago at 48K in Dinan service.
No modification on this car, it is mostly used for daily driving.
Mileage is 50K now.

I went to dealer and asked them if there are recommendations.
The guy said $175 for the inspection, if something is wrong, then more. He said common is sensor or CAT. Price is $500 for sensor and $2-3000 for the cat.

Should I just let the dealer work on it? Or should I just ask Dinan service to check, it may be cheaper?

On the net, some people recommended to drive it for 20 minutes before doing the test. Does this really work?

I lived in the Fremont CA, can anyone recommend a smog station? Not just test station?

Thanks

Supposing you're not throwing an error lite: Use techron fuel additive to clean the injectors so they spray properly, a fine spray versus clogged/droplets. Do not cheap out on the $2 stuff, get techron. bg44, redline.
After you've run that thru the tank, When you get ready to have the test done, the deal about driving is to get *and keep* the cats hot.
So knowing a time when they're not busy at the inspection lane is really useful, as when you sit in a line for 20 minutes at idle, the cats cool off and the engine loads up. Since the goal is to get them hot, drive in lower gears than normal for 20 minutes keeping the RPM up to 3000 or so, hopefully at highway speeds, quickly getting to the inspection place w/o going thru slow traffic.

If you're throwing check engine codes, get those fixed first, but if the o2 sensor is bad you should be throwing a code. I think cats are warranted to 100k miles by law, and they shouldn't normally fail at 50k.
Let us know if it works for you, it certainly has for others.
Good luck
ADS

Sunnyvale area. I have 2 that I have used. One guy did let me adjust timing outside of spec on my Honda/B18c swap (which was BAR certified) to get it to pass.

Sounds like your car needs new CAT. You should be under the CAT warranty still (I thought it was 7 years, 80k miles, separate from the car warranty).

I used to use Chevron station before joining Costco.

Is the quality of gasoline lower than Chevron?
Sometimes I just have doubt how can Costco sells cheaper gas.

Thank you

Maybe putting in 100 octane wouldn't hurt either.

Costco, Sam's, indepentent dealers, uses "spot gas," gasoline bought on the open market. Insufficient detergents cause clogged fuel injectors and also cause build up of crud on intake valves.

The EPA mandates a minimum level of detergents. But, GM, BMW, Toyota, Honda, and VW have set a higher standard called "Top Tier" gas. They did this because they were having warranty claims with rot gut gas and cars with clogged injector and deposits in intake valves don't pass emmission tests. It's noteworthy that Exxon and BP/Amoco don't meet the standard. Shell, Chevron/Texaco, 76, and Conoco/Phillips.

http://www.toptiergas.com/index.html

Actually, gasoline in pipelines is all the same. The quality brands add detergents before it's delivered to the dealers.

http://en.wikipedia.org/wiki/Methylc...se_tricarbonyl

HC hydrocarbon.

Just another curious question, on the web, says this categoy failed means the oil is not burned completely.

Shouldn't this affect the mileage?

I kept my receipts for filling up the tank, my mileage does not vary much between each fill-up.

What is your opinion?

So, running with your theory, increased HC and no decrease in mileage would suggest bad cat's.

Or this is just a very minor portion of gas. It has no impact on the mileage. Just curious ...

I am not expert in this...that is why I am asking the web.

I believe the CAT and other smog related components carry a federally mandated 8 year warranty.

-- Lee

Today I was thinking to send the car to check at Dinan mt view.
Arrive there and the gentleman there told me to do the test again with the same recommendations you guys said. Drive hard before test.

So I did that. For the last 10 min, keep rpm at 4000-5000. Total driving time is about 50-60 minutes on freeway. (Fremont to Mt View then back to Fremont)
Before the actual test started, the car was idle for about 5-10 min.


It did pass this time.

pass result: HC 15 mph 23 , 25 mph 12 (failed result was both 85)
CO and NO sections are both reduced great amount too.


My own thoughts,

1. Beofre making a trip to the dealer, ask the web (thanks to you viewers here)

2. Sign-in person at the dealership may not have good knowledge on what customer should do before spending the money. ( if I directlty go dealership, i think minmum 200 dollars ) I will continue to have my service at Dinan Mt View.

3. Regarding the type of gas, I feel there is no difference.
But adding the techron concentrate seem to make my SMG shifting smoother and at lower speed smoother too.



Thanks again

Might be the guy in your car doing the test originally was modulating the throttle a lot, this might cause it to run really rich, giving you higher HC numbers.

Or your CAT's might be getting "weak" and they needed to be really hot to pass.

Either way, Congratulations! You are set for 2 years.

I went to the same smog test station, the same guy did the test.

The only difference is the time of driving. From my home to the test station, less than 5 miles.

During the first test, actually he did try to warm up the car on site, he ran the test 3 times and all failed.
That is date I asked the web for help.

This notice was a bit too late for me....

How many people are going to do this fix?

Thanks