MyE28.com

I took the S2 for a Virginia emissions test. I figured it would fail because I have only done basic tuning to idle without any tuning tools.

I was suprised it easily passed the 3 tests at 25mph and easily passed 2 of the 3 tests at 15mph. It failed the CO% at 15mph. The limit is 0.32 and it tested at 0.35.

Any ideas on what I can adjust to bring this down are welcome. The number is so close, I could probably pass by just adjusting something, but I don't know what affects that number.

CO is a function of how rich the engine is running. I would first check that stuff like the oxygen sensor, temperature sensor, and other emissions related controls are working. (Bad O2 connection initially made my fairly stock 533i fail with too much CO.) I'm not certain what engine management you are using, but if you have been playing with fuel maps, leaning the light duty maps a hair should reduce the CO. (Don't go too far, or the exhaust temperatures and NOx will spike.)

Ya,
Virginia seems to have the same tests as CA, but we measure here in PPM.

Sounds like the low throttle is slightly rich. Adjust down fuel there. Or add some additives like toluene/alcohol will work well also.

RussC

slip the emissions guy a $20.....

Just kidding. Ive heard of CO% being tripped up by somethign as bad as a very dirty air filter or a bad fuel injector. When were the basics changed like spark plugs, rotor, cap, wires, o2 sensor and air filter? Ive also heard that if you go with premium gas it burns cleaner and can pass emissions a little easier. I guess its like those detox drinks for drug tests, just take 3 hours prior to testing.... What kinda of idle tuning did you do ?

Yellow2 wrote:slip the emissions guy a $20.....

Just kidding. Ive heard of CO% being tripped up by somethign as bad as a very dirty air filter or a bad fuel injector. When were the basics changed like spark plugs, rotor, cap, wires, o2 sensor and air filter? Ive also heard that if you go with premium gas it burns cleaner and can pass emissions a little easier. I guess its like those detox drinks for drug tests, just take 3 hours prior to testing.... What kinda of idle tuning did you do ?

Idle isn't an issue, the test is at 15mph on rollers.

All those things can help. I don't believe premium fuel makes a difference, as it a cure for misfire, and at these low RPM, misfires aren't a real problem(?).

RussC

honestly all i did was make real nice with the guy and he hooked me up beyong belief......... my car would def fail the gas cap test (as the r1 gas cap does not seal properly), the guy just looked at it and literally said "fuck it!" then they let me do the revving while the car was on the dyno, all he had me do was rev the car to 1100 RPM, hold it there for 1 minute two times, got me a print out and said "enjoy the car buddy!"

russc wrote:I don't believe premium fuel makes a difference, as it a cure for misfire...

From which orifice did you pull that? Premium fuel is not "a cure for misfire." It reduces pinging and allows for more combustion pressure because it burns cooler and for a longer period. If anything, running premium fuel would increase misfire.

As for it making a difference, I doubt it will with regard to CO, but it makes a noticeable difference in NOx.

Steve in No Va wrote:Any ideas on what I can adjust to bring this down are welcome. The number is so close, I could probably pass by just adjusting something, but I don't know what affects that number.

1) Uninstall turbo kit.
2) Ship it to me.
3) Pass emissions easily.

.
.
.
.
.

Hey guys, I have a 535 and it's gonna have trouble passing PA emissions. Any tips? ;-)

-tammer <--cracking myself up, gawd i need some sleep

Tighten the AFM spring a notch or three. Ideally, you should have a wideband O2 for tuning, it makes things MUCH easier.

Jeremy

Steve

Check your PM's

Shawn D. wrote:

russc wrote:I don't believe premium fuel makes a difference, as it a cure for misfire...

From which orifice did you pull that? Premium fuel is not "a cure for misfire." It reduces pinging and allows for more combustion pressure because it burns cooler and for a longer period. If anything, running premium fuel would increase misfire.

As for it making a difference, I doubt it will with regard to CO, but it makes a noticeable difference in NOx.

Gee Shawn, I guess I pulled it from my ASS. I consider pre-detonation(ping/knock) a type of mis-fire. The combustion process did "miss-fire", as the spark didn't ignite it!

Premium will not help the car pass a smog test, for the most part. The super light load the smog roller system puts on the car will not benefit for the advantage that premium gives. Unless the light load advance curve is so far forward your car will pre-detonate at idle practically.

RussC

russc wrote:

Shawn D. wrote:

russc wrote:I don't believe premium fuel makes a difference, as it a cure for misfire...

From which orifice did you pull that? Premium fuel is not "a cure for misfire." It reduces pinging and allows for more combustion pressure because it burns cooler and for a longer period. If anything, running premium fuel would increase misfire.

As for it making a difference, I doubt it will with regard to CO, but it makes a noticeable difference in NOx.

Gee Shawn, I guess I pulled it from my ASS. I consider pre-detonation(ping/knock) a type of mis-fire. The combustion process did "miss-fire", as the spark didn't ignite it!

Well, misfire is traditionally considered to be the spark plug not being able to properly ignite the mixture due to improper fuel/air ratio, weak spark, fouled plug, and/or spark scatter. Misfiring is not ping/knock/detonation, as ping/knock/detonation isn't "firing" in the first place. Ping/knock/detonation is ping/knock/detonation and misfire is misfire.

russc wrote:Premium will not help the car pass a smog test, for the most part. The super light load the smog roller system puts on the car will not benefit for the advantage that premium gives. Unless the light load advance curve is so far forward your car will pre-detonate at idle practically.

I see you covered yourself by using the caveat "... for the most part." I can tell you it has certainly worked on my car!

Another vote for premium. It helped my old 528e get through the idle check we used to have here in CT. Premium gas gave the extra edge it needed. Car had failed on NOx.

Jeremy

Thanks for all of the ideas and insightful conversation. I am already running premium gas and the injectors and exhaust system are new. I will bump it another notch or two on the AFM, add some octane boost and maybe lean out the RRFPR a bit. Hopefully that will work.

The rising rate only comes into play under boost. If the car is running well otherwise, I'd leave that alone.

Jeremy

Jeremy wrote:Another vote for premium. It helped my old 528e get through the idle check we used to have here in CT. Premium gas gave the extra edge it needed. Car had failed on NOx.

Jeremy

Yea,
It may help NOx, but just a little. It wont help HC or CO. If your car is right at the testing edge, just the variation in testing parameters can make you pass and have nothing to do with the grade of gas used.

RussC

High CO, change the oil if you haven't done so. If you had fresh oil in the crankcase, you might want to try leaning the A/F mixture just a touch.

Rich

Thanks all for the input. I tweeked the RRFPR back half a turn, clicked the AFM spring over a notch and added fuel injector/valve cleaner.

This is one clean burning monster. Its emissions went down across the board except in HC ppm at 15 mph. The CO% went from .35 to .09 and it passed with flying colors.

Good work Steve.

Beautiful

RussC

Fate works in mysterious ways. Last night a neighbor's empty SUV rolled down the hill that my house is at the bottom of, and used my 318ti Sport as a means of braking. Luckily, my 535is passed emissions earlier that day and I went to the DMV this morning to get my 07 stickers so the car is legal. I guess I'll be driving it for a while as my daily driver.

I look on the bright side. The damage was superficial, although it will need a hood, quarter panel, M3 front air dam and probably a little pulling of the front substructure. It needed a repaint anyway. This way, I only have to pay for half a paint job.

On another note, does anyone know where the 25amp fuse for the power windows is located? All my windows stopped working at the same time and the under hood fuse is okay and I replaced the relay switch under the dash and they still didn't work. The Bentley manual shows a 25amp fuse in the system, but it isn't by the relay, so I was wondering where to look for it.

Theres no fuse, just the 25amp breaker on the drivers kickpanel. Bentley is confusing.

RussC