Has anyone else had problems with their early Cooper S passing emissions? I bought my CooperS two years ago. It passed emission fine when I originally tagged it. Now, two years latter, up for emissions renewal, I have failed four times in the last month and a half. First attempted, I got a 4.50 (1.50 passes) reading on Nox. Thinking there should be no reason other than tune-up, I changed the plugs, upgraded the coil pack, cleaned the air filter, and ran two cans of Techron thru the gas tank. Attempted again and got a slightly higher reading. Back to the drawing board, Remembered the Cat make a rattling noise So, I replaced the Cat. Tested again, 1.79 (1.50 passes) Very close but still FAIL. A mechanic suggested we checked DTC (computer diagnostic). Check fine with no error codes. We did oil and coolant change. Tested again 1.61 (1.50 passes) Arrrrrrghhhh !!!! I am a wits end on this does anyone have any suggestions

 

Did they replace the cat under warranty?

There is a"pre"cat just off the down pipe, has that been modified? What other mods have you done to the car? How old are the o2 sensors?

 

May or may not be related, there have been postings about the O2 sensors failing
and Mini extending warranty coverage for '04 thru '06 cars.

Hope this helps...

 

Yeah, when I first read your post I would say Oxygen Sensor issue. You can be g2g and not get a check engine light because the sensor is still within tolerance, but obviously your cat failed for a reason! I would try replacing just the front sensor. Because that is the one that actually adjusts mixture the second one is just a verifier of the cat doing its job. The only other thing I can think of is your PCV, and EGR circuits, (does the Mini have an EGR circuit?) That little bit of crankcase gases, or Exhaust gas, put back into the intake stream is designed to lower combustion temps, (which is exactly what the NOX reading comes from) and the software is setup to compensate for it all working properly.

 

No the cat was not replaced under warranty. I have a MiniMania Header, Now have a MagnaFlow Cat, and Magnaflow Cat back exhaust. O2 sensor is still original (40k miles). I was not sending and error for O2. Thanks for helping with the Brainstorming...

 

Does the MM header include the pre-cat like the stock unit?

 

Yes, the pre-cat is where the O2 sensor plugs in...

 

The O2 forward sensor sounds good. You are so close to passing. If you do the forward O2 also pour in the emissions juice to make sure you pass.
Here is a link of one of the manufactures of this stuff
http://www.protecusa.com/tbpuragas_emissions_test.htm

 

Colorado Springs may have different emision standards (or lack of) than up north. Not sure I can help you. Just a few ideas: is the same facility doing the testing? May see what a different station checks. Is the car nice and hot/warmed up prior to test? How often do you open it up on the freeway?
Short driving distances and cool engine could be an issue.
Mind you, these are just ideas, not any solutions to you exact problem.

I did have luck passing emisions with "Run it down the highway" (15+miles)
trick. It was with a different car, but it may help you.
Bryan

 

I have been going to the same station and will be going to a differant station on the next attempt. I have also tried warming up the car before going in. Problem here is there is alway a line, giving time for any heat to cool-off... I Am So Close, I think that I am going to try the acetone trick (recommended by a couple of mechanics now). Thanks Again, I will keep you posted. Wish me luck, RS

 

I have decided to go the extra mile and also replace the forward O2 Sensor before my next test. So far, It looks like MiniCarParts.net (Atlantic British Ltd) has the best price on these. Has anyone had any experiences with buying their O2 sensor? Some sites, list thiers as MiniBmw OEM, some are listed a Bosch, MiniCarParts, Does not say... ???

 

Can't tell for the minicarparts.net picture what it is, I guess you could call them. I put several up, RockAuto and thepartsbin too.
http://www.minicarparts.net/Parts/M3095.cfm
http://www.thepartsbin.com/guides/mi...en_sensor.html base
http://www.thepartsbin.com/catalog/?...Mini&md=Cooper Specific to Mini
http://www.rockauto.com/catalog/x,ca...,parttype,5132

Oh and apparently, the OEM MINI plug is worth about $100 for that MINI plastic part.

 

So have you tested again?

 

I graciously offer my services:

Transfer the car to me (as a free gift, so I don't have to pay taxes). I will title and register it in FL where we have no emissions testing. Then you insure the car yourself in CO.

What's the matter, don't ya trust me? hahaha

 

Jazzop, I wont be need your very generous offer. I finaly PASSED!!!

To update everyone on my ordeal: Following the advice of many on NAM, I replaced the precat O2 sensor and run a 1/4c of Acetone in a tank of gas. When back to emission (5th time) and FAILED. The Nox reading actually when UP from 1.61 to 2.16. So, Very Frustrated, I returned to my new friends at Peak Eurosport. Changed to "colder" plugs and put 3 gallons of 100 octane fuel. They strongly suggested, getting the car good HOT and if there was a line to go back another time. Just this morning, Drove to a emissions place on the opposite side of Denver (Getting her Good and HOT). When I arrived, there was a little bit of a wait but, still decided to wait, maintaining about 2000rpms (keeping up the HEAT). When I got to the bay, I told the guy that this was my sixth time and needed her to pass. He smiled and said "I'll make it pass". There must be some kind of trick because, I did pass with a 1.06 Nox. When I pulled away, the tester honked from the car that he was testing and gave me a thumbs up. Thanks for the input and help, Hope to motor with you soon. Richard "CooperRs"

 

Cooler plugs may have helped. High Nox values are typically related to lean mixtures and hot cylinder temps.

 

Hey if you do get sensors thru mini carparts make sure its the bosch sensors i got some off brands thru them at one point and they never cleared my cel as soon as I put in some bosch stockers no cel any longer. They may have changed it i dunno.

 

Sweeeeeeeeeet! You are legal again!

 

Its been two years since my emmisions nightmare, When back last month - FAST PASS!!!

 

Years ago when I worked at a speed shop we used to pour some methanol in the tank to reduce Nox. Its been a while, but I would think that would still work to produce some clean burn issues?? Burns clean and cool. A little combustion chamber clean up and emission fix. Just saw the thread and would like to see any responses.