Hello there and welcome to the BMW Car Club of America.

If you are a BMW CCA member, please log in and introduce yourself in our Member Introductions section.

2002 530iA CA smog check fail

Discussion in 'E39 (1997-2003)' started by cterlizzi, May 16, 2013.

    • Member

    cterlizzi

    Post Count: 3
    Likes Received:0
    Hi there... Bought this for my wife in TX and never had a problem over there... All stock except for K&N air filter. However when we tried to smog in CA we get this. 130K miles.

    15 mph
    HC max 51, meas=15, CO max 0.48, meas=0.01, NO max:419 meas= 1067 Fail

    25 mph
    HC max 35, meas=13, CO max 0.46, meas=0.01, NO max 706 meas=242 Pass

    We've seen some threads on forums about running 87 octane vs standard 91 octane and letting it run for a while before testing it, but those seem to be mostly for CO issues... What about for NO issues?

    Appreciate any and all contributions.
    • Member
    • Technical Service Advisor

    charlson89

    Post Count: 1,146
    Likes Received:55
    High NO or nitrogen oxide is normally caused by hot combustion temperatures. Normal things that cause this are bad cats (unlikely in your case), engine overheating (agian unlikely in your case or you would have noticed it). EGR valve which in your engine is done by the vanos system. If the car is running good no weird surges or running rough or check engine light then I wouldn't go with a vanos issue. I would check to make sure your oil seperator has not failed and is sucking unmetered air into the engine causing a lean issue and thus high NO. If all looks good then do a tune up to the car, plugs, fuel filter, injector flush to break the carbon off the valves and combustion chamber as well. In high mileage vehicles carbon deposits can form in the combustion chamber causing high compression and thus increases the chamber temp and creates high NO. Hope some of this is helpful to you and if you have any other questions just ask.
    • Member

    MGarrison

    Post Count: 2,868
    Likes Received:147
    Ah... I hope Charlson and others can chime in, all I can do is throw some not-so-expert guesses at ya...

    I googled this up -

    http://www.smogtips.com/failed-high-NO-nitrous-oxide.cfm

    So that's saying running lean, EGR system issues, or cat. converter issues.

    Unfortunately, lean running can have a lot of causes, that article mentions several, and I'm sure there could be others such as fuel injector issues... the M54 has vanos, BMW's variable valve timing system, seems plausible that could be a problem if it's leaking or malfunctioning or... something; fuel supply issues - fuel pumps, fuel pressure regulator, etc.

    In short, there's a lot of possible causes for running lean, and it would take some systematic checking starting with the most likely possibilities to narrow it down to try and resolve why you're getting no-pass readings at a lower speed.

    Obviously something is a good bit different between running at 15mph & 2then 5mph, so that must indicate something, but what, I don't know, just not my knowledge base - so, hopefully someone will have some ideas on where to start and go from there!

    Any M54 experts around?

    ------------
    edit - lol, Charlson replied after I started and finished before me... so, yeah, what he said! :D
    • Member

    cterlizzi

    Post Count: 3
    Likes Received:0
    Thanks, Charlson & Mgarrison... Forgot to mention car has 128K and had full 120K at 120K and full oil at 127K... So I'm thinking tune up would be the less likely issue... I'll look into the oil separator...

    BTW, it has a K&N air filter... More air flow good or bad in this situation?
    • Member

    cterlizzi

    Post Count: 3
    Likes Received:0
    Oh, and just found out wife put in a tank of 89 octane vs the normal 91 (93 in TX)... Still 1/3 full of the 89 stuff...
    • Member

    MGarrison

    Post Count: 2,868
    Likes Received:147
    I wouldn't expect whatever additional airflow you might get from a K&N to be more than the stock fuel maps can adjust/compensate for... I suppose there might be an outside chance that it might tip the balance in case of other issues that put it on the bubble for being in spec - however, if the emission control systems are working fine & the air filter would make that much of a difference, you might be getting check engine lights all the time.

Share This Page