Failed Emission Test

[frankh991]

Hello...
Just joined and love this forum...I just purchsed a '94.. 525i
with 120k miles.... woe be to me! brought it home..
changed extremely dirty oil/filter....changed plugs(a little oil
on them)...now it fails the emissions test ...high CO/HC's..
Any suggestions about further tests/repairs will be appreciated...I will test O2 sensor next..What about EGR
and the other pollution type stuf ??? I could "##@@@%%%**" the previous owner for abusing a lovely car....
Thanks

[winfred]

no egr no air pump or any other crap like that, id look for air leaks like on the hoses coming off of the valve cover, the big one eventually goes to the air boot at the throttle body and the small one goes to a nipple at the idle control valve, usually these are rotted off on m50s

[winfred]

floging it real good to get the cat good and hot helps too

[Tiger]

How high is your reading... high itself doesn't mean a thing.

[frankh991]

How high is your reading... high itself doesn't mean a thing.
HC's at 529ppm ..limit is 220
CO at 2.90% .. limit 1.20...
I will check for vac leaks also... These seem to high just for a good heat to help.
Thanks....

[Tiger]

Whoa... that is very bad. That is serious. Vacuum leak can do this but I think it is more than that... when is the last time you changed the O2 sensor? I don't think just by changing O2 sensor will fix this problem... more diagnostic is required.

[frankh991]

Let me test O2 sensor and check for vac leaks/ and will advise of results this weekend...Thanks...

[Tiger]

With a reading that high... I suspect it has something to do with fuel system... possibly the MAF... you really need a diagnostic machine to read what is going on with the engine.

Cat can't burn all that excess fuel. O2 sensor can only tell the engine that too much fuel is coming out of the engine.

[540i-94]

What is high CO is usually O2 sensor, and happen to me in my other car, the fuel injection gasket was leaking. What about CK ENG light, is on?. I hope just be O2 sensor, change it.

[frankh991]

was trying to pass emissions test 1st before going to my local Pirate...... But will change O2 sensor and have Testing service to recheck...I have 2 more free tests before I have to pay for another one.. and I have 2 more weeks on the Temp Tag...Thanks.

[DueyT]

was trying to pass emissions test 1st before going to my local Pirate...... But will change O2 sensor and have Testing service to recheck...I have 2 more free tests before I have to pay for another one.. and I have 2 more weeks on the Temp Tag...Thanks.


Frank, was the car nice and HOT when you took it in? If your NOx was good (nice and low) then you should go out for an Italian tune up then roll onto the drums nice and hot. You may be out by a factor of 2+, but my neighbour (he owns a shop with an E-test setup) has seen lots of guys come in with a car that's barely up in the operating range and fail (usually just be a bit.) He now tells everyone before the test to make sure the engine is nicely warmed up (not just needle in the middle).

That said, do a stomp test (http://www.bmwe34.net/e34main/trouble/engine_codes.htm)and see if they're any O2 codes (1221 and 1212 come to mind). You could also have some sick/plugged cats if the engine was spewing that much raw fuel!

Cheers,
Duey

[frankh991]

Thanks Duey.....
The wife said it was warmed -up when she had it checked....but you know women and "warm-ups"...I will
do a stomp test tomorrow..but the guy that I got this car from was a pig...so I will bet the O2 sensor is just the 1st part of my problem...Uh? what's a "cat" you speaka the bmw lingo betta than me..... Frank

[DueyT]

Thanks Duey.....
The wife said it was warmed -up when she had it checked....but you know women and "warm-ups"...I will
do a stomp test tomorrow..but the guy that I got this car from was a pig...so I will bet the O2 sensor is just the 1st part of my problem...Uh? what's a "cat" you speaka the bmw lingo betta than me..... Frank
Cat = catalytic converters. They are a component of the exhaust system that is designed to catalyze (enhance combustion) of unburned hydrocarbons in the exhaust stream. They are designed to work with small amounts of unburned hydrocarbons. Large quantities, such as when a car goes into open loop because of a failed 02 sensor can increase temps in the converter to extreme levels and actually melt/fuze a large portion of the cellular structure of the convertor's interior. This then radically increases the backpressure in the exhaust system and really chokes the car. Turns it into a wheezing, slow sedan! *ughh*

The stomp test should show if you're holding an engine code. I had a quick chat with my neighbour after my earlier post and he said a car operating in open-loop (no sensor feedback due to a failed sensor...or if the car hasn't warmed up yet [ above the blue mark on BMW temp guages]) would result in very high HC/CO levels.

Hope that helps.

Cheers,
Duey

[frankh991]

Well the o2 sensor was fried....New one is working great....the next step is to retest for emissions and if this doesn't work then I will proceed to the "cats' per what Duey suggested....i would bet the O2 sensor has been bad for a long time and the cats are also fried by now....i read somewhere that some after market cats don't have enough volume?? any suggestions on what/where to buy some that work well at a decent cost...I can get my local friend to cut and paste the new ones in.......oh by the way the stomp test gave me 1221 over and over again for about at least 10 times(after 10 I shut it down) how many codes does the bugger hold...I could not
clear it yet since it continues to spit out 1221's ...
Thanks
Frank

[winfred]

aftermarket cats are fine on 95 and older cars (obd1), the computer will keep flashing whatever code/s it has in memory, unplug the brain if you don't want to disconnect the battery to clear the codes, the brain is opossit the fuse box under the hood, the cover has 4 + screws, the engine computer is the one closest to the windshield, a minute or so will do



Well the o2 sensor was fried....New one is working great....the next step is to retest for emissions and if this doesn't work then I will proceed to the "cats' per what Duey suggested....i would bet the O2 sensor has been bad for a long time and the cats are also fried by now....i read somewhere that some after market cats don't have enough volume?? any suggestions on what/where to buy some that work well at a decent cost...I can get my local friend to cut and paste the new ones in.......oh by the way the stomp test gave me 1221 over and over again for about at least 10 times(after 10 I shut it down) how many codes does the bugger hold...I could not
clear it yet since it continues to spit out 1221's ...
Thanks
Frank

[frankh991]

Thanks winfred..
did you get your stump jumper?? i was on that thread when this came in...good luck
frank

[winfred]

crack head wasn't at the auction (you'd need to meet him) so the boss didn't get to haggle with him, so it will be into next week before i get my beast, mom even likes it when i drove her by it, she wants to go half on it with me http://members.cox.net/wdixon27/burnout.gif

[frankh991]

Success!....Thanks guys..,With six new plugs and a new O2 sensor the car passed wit 0 emissions registering....Thank goodness I don't have to replace the cats...now i can start on my thrust arm
replacements....Thanks again for all the help...
frank

[Unregistered]

hey duey t or frank. surfing the internet for some tips/tricks on passing emissions. i have failed for HC. then changed the plugs and and passed with flying colors...for HC. EXCEPT NOW i failed for NOx

the standard in nj. is 213 for hc i went from 800 down to 103 with plug change

the standard in nj is 1483 for nox i failed with 1565.

should i cool the car off before i go in to inspection as it is a long and trafficky drive to the inspection station

please email me
duvam@earthlink.net

if you reply to this as i am not a a member of this board and have been surfing for 5 hours now and cant find the right answer....aaghh
thanks
md

you still there



[QUOTE=DueyT]Frank, was the car nice and HOT when you took it in? If your NOx was good (nice and low) then you should go out for an Italian tune up then roll onto the drums nice and hot. You may be out by a factor of 2+, but my neighbour (he owns a shop with an E-test setup) has seen lots of guys come in with a car that's barely up in the operating range and fail (usually just be a bit.) He now tells everyone before the test to make sure the engine is nicely warmed up (not just needle in the middle).

[Karl]

High HC and CO means a rich mixture. I'm with the advice to check toe O2 sensor. Failing O2 sensor will put out low voltage (looks like lean to the computer), so the computer will enrich the mixture to compensate. The car is actually running rich

Vacuum leak will make the car run lean.

[frankh991]

according to my "new book" by jack erjavec..fuel(hc's) + o2 combust to form water and co2..however since a lot nitrogen is present in intake air(naturally)..the optimum at correct conditions is no NOX exhaust....Nox is formed only when there is very high combustion temps..can be caused by cooling system probs..carbon buildup on pistons(higher compresion ratios) ..defective EGR system and lean mixtures....In summary...hot is good for NOx
formation...
frank

[DueyT]

MD, yes... My neighbour mentioned that since you're good on HC by a good margin, let it cool right down then have the test done. It's close and you may just make it. The idea will be to not let it sit around idling or running to long before it goes on the rollers. Cool down means the entire system, engine, cats (etc...) but the best is a "start from cold" engine. Will also try to e-mail you but my work SMTP-server is dead right now.

Hope that works,
Duey




hey duey t or frank. surfing the internet for some tips/tricks on passing emissions. i have failed for HC. then changed the plugs and and passed with flying colors...for HC. EXCEPT NOW i failed for NOx

the standard in nj. is 213 for hc i went from 800 down to 103 with plug change

the standard in nj is 1483 for nox i failed with 1565.

should i cool the car off before i go in to inspection as it is a long and trafficky drive to the inspection station

please email me
duvam@earthlink.net

if you reply to this as i am not a a member of this board and have been surfing for 5 hours now and cant find the right answer....aaghh
thanks
md

you still there



[QUOTE=DueyT]Frank, was the car nice and HOT when you took it in? If your NOx was good (nice and low) then you should go out for an Italian tune up then roll onto the drums nice and hot. You may be out by a factor of 2+, but my neighbour (he owns a shop with an E-test setup) has seen lots of guys come in with a car that's barely up in the operating range and fail (usually just be a bit.) He now tells everyone before the test to make sure the engine is nicely warmed up (not just needle in the middle).