1995 525i failed emissions testing

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AndrewD

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1995 525i 5MT, 318k miles Didn't fail but much, any tips on getting it to pass? I will change the oil and filter before going in for the re-test. It has 91 in it now, considering trying 87 the next time (lots of mixed opinions) 15MPH (fail) RPM 1736 CO2 - 14.7 O2 - 0.0 HC (ppm) - MEAS 81 MAX 112 [FAIL] CO% - MEAS 0.14 MAX 0.47 NOX (ppm) - MEAS 289 MAX 683 25MPH (pass) RPM 1872 HC (ppm) MEAS 52 MAX 46 [FAIL] CO% MEAS 0.07 MAX 0.44 NOX (ppm) MEAS 39 MAX 692
 
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Sorry, this is the correct report. 15MPH (fail) RPM 1736 CO2% - 14.7 O2% - 0.0 HC (ppm) - MEAS 81 MAX 112 [FAIL] CO% - MEAS 0.14 MAX 0.47 NOX (ppm) - MEAS 289 MAX 683 25MPH (fail) RPM 1872 CO2% - 14.7 O2% - 0.0 HC (ppm) MEAS 52 MAX 46 [FAIL] CO% MEAS 0.07 MAX 0.44 NOX (ppm) MEAS 39 MAX 692
 
spark plugs oil change and warmed up a little hotter, maybe a highway run and a parking lot idle at the test center.
 
I've heard that tc-w3 may reduce some compounds in regards to emissions but I haven't seen it myself so I cannot say for sure. Would acetone/toluene/xylene improve emissions? They reduce the surface tension of fuel which can help it burn more completely. Believe it or not Lucas upper cylinder lube may also help. It contains polyisobutylene which is known to improve fuel economy buy helping fuel more completely. Unless you are due for an oil change there's no point in changing it just for the emissions test. Here's what I would do. Wait til the fuel tanks hits 3/8-1/2 tanks or so. Then add a fuel system cleaner high in pea such as "guaranteed to pass",redline,techron or whichever has the highest pea content or what's easy to get. So add them to the gas. Now make a point of driving the car at high rpm and lots of pedal for the rest of the tank. The cleaner will do its thing while you are operating really hot with lots of cylinder pressure which all on its own will break loose rings if they are coked up and the increase in air velocity will accelerate the cleaning process. This will also heat the cat up hot and hopefully the heat and increase in velocity,as well as the pea in the fuel which from what I understand loosens and removes deposits by attaching themselves and encapsulatingit,insulating it which prevents re-deposition when expelled. This same process,and the extra heat as well as the air velocity being so much greater it may,for the short term operate until everything gets caked on again. People don't realize how important it is to drive an engine hard sometimes. It heats up the exhaust yway more and the increase in air velocity acts like a tornado whipping everything inside the intake up cleaning the maf or AIT which helps keep sensors clean,heats the oil up and increases pressure and velocity which helps contaminants dissolve and disperse better as well as moving any larger deposits where less oil is able to arrive. No need to drive like a retard or anything just go on a highway and drive in a lower gear. 4000 rpm is a good target with some varying pedal,going full throttle but not just mashing the pedal,gradually get yourself there. It's the jack rabbit mashing of the pedals that wreck the mechanical links,so as long as your increase torque by pedalling in lightly it's not really that hard on the drivetrain. A friend of mine who has an automotive recycling facility once told me 1 quart of acetone in half a tank of fuel in his LS powered retrieval units made them pass their emmisions. He's in Alberta somewhere they have to get sniffed. Before driving the additized fuel I suggest unhooking the battery and clearing the ecu. That erases the learned values starting you off at 0 again and clearing any check engine lights. After the Italian tune up erase the ecu again. Because the sensors will be cleaner they will be more accurate which will affect the exhaust gasses. But this is just me. It would be nice to have solid proof that some additive,and an Italian tune up really does make a car pass. We have a test mule here guys. A real world test. Real data from someone with no skin in the game. Please keep us informed
 
Originally Posted By: Clevy
Before driving the additized fuel I suggest unhooking the battery and clearing the ecu.
No, don't do this, it'll erase your learned fuel maps. The slighly high HCs are unburned fuel sneaking through. Though it might be a lazy o2 sensor, fresh and good ignition parts should zap those extra molecules into nonexistence.
 
High HC usually a lean mis fire. Before going back check (or do) an oil/filter change, tune up, verify proper base timing, properly inflate tires and a carbon blast fed thru throttle body or PCV. Do the carbon blast before the oil and plug change. Check for vacuum leaks by spraying carb cleaner around throttle body and vacuum lines and listen for an RPM increase. The lower octane might help HC but might cause NOX to increase if the engine wants to ping.Good luck and it is a shame these older vehicles are held to such a high standard when it comes to emissions.
 
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Originally Posted By: eljefino
Originally Posted By: Clevy
Before driving the additized fuel I suggest unhooking the battery and clearing the ecu.
No, don't do this, it'll erase your learned fuel maps. The slighly high HCs are unburned fuel sneaking through. Though it might be a lazy o2 sensor, fresh and good ignition parts should zap those extra molecules into nonexistence.
That's what I want. The sensors are going to be in different states of clean so I want it to start off at 0 again and simplify the learning process,to a tune that when written was emissions perfect. I saw guys doing it at the track. It helps them tune knowing they are always starting from the same spot and the computer has no learned values yet which because of the unknown state of the sensors might have ones way different then before making the computer possibly go limp I like that it starts me off at stock again. Makes adjusting simple.
 
Make sure the engine is hot. Perhaps a bit of e-85 when the tank is low add just enough so that you are at a say an e-20 mix, go do emissions, then fill back up with normal fuel.
 
I just bought the car. It's been neglected with the last couple owners so I picked it up for next to nothing without a smog. I've run a half tank (about 10 gallons) with 91 octane fuel and G2P additive used, didn't refuel and had it tested. I was able to warm the engine up but it may not have gotten hot enough due to heavy traffic on the way to the station. I wasn't able to go high speed high rpm but I was flogging it on the surface streets. Plugs were replaced by the previous owner within the last year, I personally replaced a vacuum line, swapped out a the MAF with a known working unit, and replaced the intake boot which had cracks all over. I noticed the throttle body was a little dirty (oily) but I didn't clean it out, I assumed it is normal operation, or does that indicate a problem? I expected a mess, car has had a long history of failing smog but I was surprised to see the smog numbers to be so close. I will try a diluted alcohol mix. The smog history, FWIW: BMW 5-SERIES 1995 06/24/2015 03:22 p.m. F BMW 5-SERIES 1995 09/11/2013 10:35 a.m. P BMW 5-SERIES 1995 09/05/2013 09:16 a.m. T BMW 5-SERIES 1995 09/04/2013 02:02 p.m. T BMW 5-SERIES 1995 08/16/2011 03:46 p.m. P BMW 5-SERIES 1995 08/11/2011 05:43 p.m. F BMW 5-SERIES 1995 08/08/2011 11:09 a.m. F BMW 5-SERIES 1995 07/25/2011 06:08 p.m. F BMW 5-SERIES 1995 08/01/2009 11:58 a.m. P BMW 5-SERIES 1995 07/11/2007 09:48 a.m. P BMW 5-SERIES 1995 06/16/2007 09:39 a.m. F P=Pass F=Fail T=Fail emissions device(s) found tampered
 
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As seen in previous posts, don't go hog wild pouring additives in your tank. If deposits have formed, you would have to add huge amounts to the fuel to make a difference and may damage something in the process. Do the maitenance "basics" and you will likely pass since your readings aren't that bad. I never had any faith in adding a half pint of snake oil to the many gallons of gas.Kind of like dumping ten gallons of water in a small lake and expecting the level to rise.
 
Originally Posted By: Clevy
Originally Posted By: eljefino
Originally Posted By: Clevy
Before driving the additized fuel I suggest unhooking the battery and clearing the ecu.
No, don't do this, it'll erase your learned fuel maps. The slighly high HCs are unburned fuel sneaking through. Though it might be a lazy o2 sensor, fresh and good ignition parts should zap those extra molecules into nonexistence.
That's what I want. The sensors are going to be in different states of clean so I want it to start off at 0 again and simplify the learning process,to a tune that when written was emissions perfect. I saw guys doing it at the track. It helps them tune knowing they are always starting from the same spot and the computer has no learned values yet which because of the unknown state of the sensors might have ones way different then before making the computer possibly go limp I like that it starts me off at stock again. Makes adjusting simple.
It's not track power he's after, it's emissions, which is what the computer tries to teach itself to pursue. If he had problems with knock retard or power loss a fresh slate might help... but if he has a tiny vacuum leak or a MAF that's drifted in calibration (within reason) the feedback controls will have memorized such a change.
 
It may be the cat, cars that require premium fuel require premium fuel. Another tank of premium may help. My brother in law insisted regular fuel is OK in their new Mercedes. It ran like c and the first CA emissions it failed. It needed new cats which he talked the dealer into replacing, probably since they buy a new MB every eight years or so. It says right in the manual don't use regular or the cats can be damaged. Hopefully you have a car that needs only a full tank of premium. In CA technically it isn't your car yet, it still belongs to whoever sold it to you. Without a smog cert a seller can't legally sell and transfer the car to you. The DMV is very clear, the seller must provide a smog cert.
 
The history shows that this must have belonged to me or elje in the past :-) Before getting "P" the car had always got "F" or "T" on the first attempt :-) I thought CA started doing OBD-II testing for all 1995 and newer cars (aka hook up the code reader) or are they still doing real tail-pipe emissions?
 
I'd run an e85 blend to enrichen the o2 in the mix, e20 to e30 should be safe for short term use. Mix some tc-w3 but don't have any in the tank when you go to test. Checking valve clearances would be a good idea as well. Putting in the proper spec oil should help too, as who knows what was actually run by the PO. I'd go for an hour drive before I got tested, but that might be tough Its also possible your stat is wrong or opening early. Check your coolant temps manually and confirm they are hot enough
 
Originally Posted By: Vikas
The history shows that this must have belonged to me or elje in the past :-) Before getting "P" the car had always got "F" or "T" on the first attempt :-) I thought CA started doing OBD-II testing for all 1995 and newer cars (aka hook up the code reader) or are they still doing real tail-pipe emissions?
OBDII began in 1996, not 1995.
 
Obd 2 was pretty implemented on a lot of cars in 95 and even some into 94. Its highly possible that's its an obd 2 car
 
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