Smog Fail. Tried previous M3F solutions... Stuck. What next?

[m3f_HoneyBunches]

Hello all.



I live in LA and have been trying to pass smog since August. I have done many things to try to pass and still haven't. Read every smog thread on BF and M3F, talked to multiple shops, some of which have "diagnosed" the problem which I then fixed... still failed. I've gathered as much info as I can on the smog problems/solutions on E36's so far, and am still stuck failing.



I contacted BAR CAP program and they did award me a $500 credit for repairs by an accredited smog place, then I proceed to contact smog places for help and they ALL tell me they can't or won't do it as soon as I hand them the BAR paper. WTF!



At this point if I can't get it to pass my options are to donate the car, sell out of state, or not use it. All of these options suck. Feel helpless and screwed.



Current as of today smog numbers:



Vehicle - 03/1998 BMW 323ic (Auto) 103k miles



15 MPH -

co2- 15.5

o2- .4

HC- 134 (MAX=55)

CO- .18 (pass)

NO- 1984 (MAX=437)



25MPH -

co2- 15.4

o2- .2

HC- 50 (MAX=39)

CO- .04 (pass)

NO- 1251 (MAX=724)



Back in April car was bogging, exhaust rattling, very little power. I suspected this to be clogged/failed original exhaust system, and I believe this is the effect of a bigger problem upstream I have yet to figure out. Car could barely make it up the hill. As soon as I experienced this I replaced the exhaust system with a complete S52 exhaust, but did not touch the engine. Sounds and feels great, no hesitation, very smooth idle and revs. Maintenance history is flawless, car was never abused, 91 octane fuel entire life of vehicle etc... Smog was due in August, and its now December



Things I have done:

Cleaned: MAF, TB's, ICV, fuel additives, seafoam. Replaced: Air filter, Air/Oil separator (PCV), To/From hoses on PCV, Intake elbow, ICV to elbow hose, spark plugs, valve cover gasket, Engine/trans/diff fluids, coolant flush with distilled h2o/refill to OEM spec with BMW blue/distilled h2o/redline water wetter, Coolant temp sensor, Fuel filter, all o2 sensors, used 100k mile S52 midpipe and muffler, plugged/de-activated the original vacuum sound flap hose that S52 muffler does not have, All new gaskets for the exhaust, flange gaskets coated with high temp sealer, and did my best at verifying that there are no leaks present in any and all of the systems. *Tested car with hot cats, heat on, plenty of cool air flow in front of car, no wait in line before test etc. And to those that still think it's the cats... I've tested this car with a used OEM midpipe that had used good condition OEM cats, and another OEM midpipe with new aftermarket cats, both fails.



No check engine/dash lights/OBC errors of any kind, and yes all of those systems work.



The things that I don't have capability of testing on my own would be things like faulty head gasket, Vanos, Air/fuel ratios, compression or leak down tests... Etc. I believe I've done all the external straight forward stuff. Any immediate suggestions? Anybody know of an E36 smog guy? Any help greatly appreciated. Thanks in advance.

[m3f_betrezra]

http://justsmogs.com/2013/05/high-hy...-smog-failure/

[m3f_betrezra]

Based on market value of non m e36 keep an eye on expenditures vs price of a different functioning e36, particularly if a shop is doing the work.

[m3f_haus]

Car barely making it up a hill has to be more than an exhaust issue (?!). I honestly can't believe a 1999 car couldn't make it up a hill but didn't give you a CEL.


Even if you don't have a CEL, grab a peake scanner or other OBD scanner and look for stored codes. Find out what your fuel trims look like (I use an ultragauge but you can grab a transceiver and an app like Torque for your phone); the car may run great but may be masking a lean or rich condition by adjusting the trims. How long have you had the car? What's the smog history? It might provide a clue if the thing has been creeping closer to failing every 2 years for the last decade or if this just started out of the blue this cycle.


I don't know the value of non-M E36's; it's probably all over the place as with the M cars, so it's going to be up to you to decide if it's worth the time and money. A 99 with only 103K miles should not be failing smog, though, even in CA. I hope you're able to solve it.

[m3f_M3n00b]

Judging by the high NO and HC it looks like your car is running lean.

Car barely making it up a hill has to be more than an exhaust issue (?!). I honestly can't believe a 1999 car couldn't make it up a hill but didn't give you a CEL.


Even if you don't have a CEL, grab a peake scanner or other OBD scanner and look for stored codes. Find out what your fuel trims look like (I use an ultragauge but you can grab a transceiver and an app like Torque for your phone); the car may run great but may be masking a lean or rich condition by adjusting the trims. How long have you had the car? What's the smog history? It might provide a clue if the thing has been creeping closer to failing every 2 years for the last decade or if this just started out of the blue this cycle.


I don't know the value of non-M E36's; it's probably all over the place as with the M cars, so it's going to be up to you to decide if it's worth the time and money. A 99 with only 103K miles should not be failing smog, though, even in CA. I hope you're able to solve it.

My 97 started failing 15mph HCs are 80k miles. Now I need to run fresh oil, plugs and guaranteed to pass treatment to make it to 54(max 54) HC

[m3f_HoneyBunches]

I appreciate all the suggestions and comments so far.



It's all me doing the part sourcing and installation so as far as cost goes for parts replacement it's not too much of a concern.



It is definitely more than an exhaust issue at this point. I strongly believe that the original cats failing and clogging in April, and not allowing much flow and barely letting me get up the hill in April was the effect of the problem. By replacing the exhaust I cured the effect, but the root cause of the original problem is still there.



Super weird that no codes were thrown at the point the cats were clogged not allowing much flow through the exhaust, or at any point for that matter so I don't have any obvious leads.



Yes, even though I didn't have a CEL I still scanned for stored codes, and nothing. Fuel trims however I haven't which I'll do next. Thank you for the suggestion, Haus.



And, I have owned the car for 5 years, since 60k miles. Never had an issue passing before, and not just not an issue but very low numbers, even two years ago.



I was parked next to a guy with another E36 the other day, and his response after I told him it wasn't passing was, "ah dude! you're ridin' dirty! E Dirty Six!".

[m3f_Maxima SE]

register it in nevada, you can pass with 1 CEL there. and give the middle finger to the nazi cali

[m3f_bluptgm3]

How did you accomplish the change from single exhaust to dual pipe catalytic converters in terms of single pre-cat and single post-cat O2 sensors?


Does the OBDII 2.5l require 91 octane fuel, as it burns slower that 87 octane.


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[m3f_HoneyBunches]

Didn't know Nevada was like that. If I end up having to sell without passing smog it might be to a Nevada buyer.



The part numbers for the M3, 328i, and 323i exhaust manifolds are the same, so I replaced the stock 323i midpipe and muffler with the M3 midpipe and muffler, no issues with fitment.



As far as o2 sensors go there are 4 on the M3 and only 2 on the 323i. But remember the manifolds are the same, however instead of sensors from the factory on the 323i manifold, the factory plugged these with removable screw in plugs. So I took the left plug from the 323i manifold, and put that plug into the right side of the new M3 midpipe o2 sensor location. This leaves the left side manifold ready for 1 pre cat o2 sensor, and the midpipe ready for 1 post cat sensor.



I used the left side manifold and midpipe locations for the sensors because they are closer than the right side in terms of distance to plug in location. But you can probably get away with either side, since sensors on the M3, 328i, and the front sensor on stock 323i (post cat sensor on stock 323i is shorter) have the same part number. However I couldn't see a good way to route the sensors if I used the right side on the 323i.



In terms of factory specification on fuel usage the manuals and books say to not go any lower than 89 octane fuel in my OBDII 2.5L M52 "323I". This engine screams by the way. Very underrated car in my opinion. Car has been great all around for the last 5 years except for this problem with smog

[m3f_betrezra]

Im thinking your mod o2 sensor arrangement is a factor.

Gl

[m3f_M-technik-3]

No mention of how old the oil is? Or did I miss this? I have not been under a 323i in sometime do they have the same down pipes as a 328i/M3 if so the adding dual cats has to help the car breath and but the O2 sensors will be off seems you would have to flash the ECU to let it know where they are.


2.5L M52 has one post O2 sensor and not two correct?

[m3f_betrezra]

agreed Mtech. Suspect O2's are not happy with changed exhaust and O2 bung placement.


Probably causing AFR issues....... and emissions issues.


Either reflash.... OR put stock pipe back on.

[m3f_Bimmerman325i]

Those numbers indicate the catalysts are not functioning at all, either due to insufficient temperature or something else.



High numbers for one species but not others would indicate lean (high NOx)/rich (high HC) AFR conditions.



You say you've tried different sets of cats and the car still fails. That's....odd. I would put the O2 sensors back in their original locations and try again, with blazingly hot cats (like, 2nd gear redlining hot). Try that, then reassess.

[m3f_bluptgm3]

No mention of how old the oil is? Or did I miss this? I have not been under a 323i in sometime do they have the same down pipes as a 328i/M3 if so the adding dual cats has to help the car breath and but the O2 sensors will be off seems you would have to flash the ECU to let it know where they are.


2.5L M52 has one post O2 sensor and not two correct?

Correct, the OBDII 2.5l 323 has a single pre-cat and single post-cat sensor in a single pipe catalyst section.

Using the the OBDII dual pipe 328/M3 catalyst section without a merge may be an issue as the single sensor that has been relocated in the head pipe ‘sees’ less total flow and hotter gases. The single post-catalyst sensor also only ‘sees’ half the gas output as it would in a single pipe.


Temporary single pipe catalyst usage may not yield enough time for re-adaptation to occur.


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