Didn’t pass smog

[waynemelllo]

So my 95 M3 didn’t pass California smog today on the low RPMs portion of the test. The car was sitting for 2 year. I put premium fuel and a can of octane boost. Ripped it up and down the street 10 times to get it nice and warm. I put new NGK plugs in it and did an oil change. The issue is I can really take it out on the freeway cause I can’t get it registered till I get the smog . Any ideas?? I bought this car for my son and he’s dying to get it on the road.

[bmwdirtracer]

You absolutely should have drained the 2 year old gas, because it's not gas anymore - it's varnish. Just smell it.

Now, I'm not saying that's the emissions problem, but varnish does not burn cleanly, and will clog the injectors too. The octane boost wasn't really a good idea either.

A smoke test of the intake system would be a good idea (You have an intake leak). Replacing the O2 sensor would be a good idea. Sending the injectors to RC Injection (not far from you) for cleaning and "blueprinting" would be a good idea.

A can of Seafoam would be good, in your new tank of gas, but you'd need to burn up that tankful and refill.

[waynemelllo]

There was very little gas in the tank when i filled up last week. This is my first BMW so i'm learning as i go. So your saying that i have an intake leak for sure? A few people told me to use Octane booster(even the smog tech) and heat the car up really well before i bring it to smog. The smog guy said it passed in the 30mph test but not the 15mph test.

[bmwdirtracer]

Your NOx emissions were extremely high in the "low speed" test, leading me to believe the engine might be running lean due to an intake leak, especially as this condition improves greatly at higher "speed". You also have high HC, a sign of incomplete combustion.

You didn't actually pass the high speed test either, you just failed it by a little on HC, but NOx was fine.

Yes, absolutely, you need your engine and cat to be hot immediately before testing. Don't worry about the octane booster; maybe the tech thought you might be getting pre-ignition from carbon deposits; but octane booster actually makes for slower combustion. That said, a tiny bottle of octane booster in a tank of gas is pretty much irrelevant anyway.

[waynemelllo]

So you think just getting really hot will do the trick to get it to pass smog? I’m changing the valve cover gasket as we speak cause oil was leaking on top of the plugs as I was replacing them

[bmwdirtracer]

No, absolutely not. You need to fix the NOx problem. Most likely cause is an intake leak/ running lean at low rpms. Smoke test.

[waynemelllo]

plug_1_m3.jpg

These are a week old plugs with like 3 miles on them. Looks pretty lean in cylinder 1. I thing your correct. The other plugs are darker

[waynemelllo]

A hose was cracked on the bottom of the rubber elbow going into the throttle body. I did a little cheater smoke test and the smoke came out of the 1 inch hose going into the bottom of the large ribbed hose going into the throttle body. It had fallen off and sliced cracked on the end. Could that be my leak?

[bmwdirtracer]

That could be one of many. Remember that all the rubber parts are 28 years old. Rather than digging around and perhaps causing new leaks, I highly recommend you replace the parts you have found to be leaking, and then get a real smoke test before heading back to the DMV.

[E36 Em Tree]

You still chasing this? As an owner of a CA M3 ive been through smog a bunch of times, fail and pass.
Your HC are due to unburnt fuel so you have an engine not combusting all the gas.... i changed my fuel purge valve (a 1 year old febi PO had installed) to a OEM BMW one. The purge valve was stuck open dumping excess fuel into the engine at lower speeds.
You NOX are most likely due to your cats going out. Replaced cats on my previous ones because the NOX wasnt going down. Also, run guaranteed to pass or injector cleaner in the tank to clean the injectors cause sometimes they get clogged or spray weird and youll be running rich.

These go out more often than people want to think. I checked mine by taking it off completely and blowing into it which let air pass (or gasoline vapor if the car is running). Should be closed until 12v is run.
https://www.fcpeuro.com/products/bmw...744150#fitment

Get 6 of these or more since youll be changing them often. Dont get anything fancy because these will do just fine plus I have smog numbers that show the engine combustion is better with these and not the 2 or 4 prongs (which I failed with).
https://www.autozone.com/external-en...962/505367_0_0

- - - Updated - - -

plug_1_m3.jpg

These are a week old plugs with like 3 miles on them. Looks pretty lean in cylinder 1. I thing your correct. The other plugs are darker

Looks like you also have oil on the plugs which means you need a new head gasket.. which is cheap and easy to replace. Oil getting into the engine can also cause the HC and NOX to be higher from what ive read.

[bmwdirtracer]

You still chasing this? As an owner of a CA M3 ive been through smog a bunch of times, fail and pass.
Your HC are due to unburnt fuel so you have an engine not combusting all the gas.... i changed my fuel purge valve (a 1 year old febi PO had installed) to a OEM BMW one. The purge valve was stuck open dumping excess fuel into the engine at lower speeds.
You NOX are most likely due to your cats going out. Replaced cats on my previous ones because the NOX wasnt going down. Also, run guaranteed to pass or injector cleaner in the tank to clean the injectors cause sometimes they get clogged or spray weird and youll be running rich.

These go out more often than people want to think. I checked mine by taking it off completely and blowing into it which let air pass (or gasoline vapor if the car is running). Should be closed until 12v is run.
https://www.fcpeuro.com/products/bmw...744150#fitment

Get 6 of these or more since youll be changing them often. Dont get anything fancy because these will do just fine plus I have smog numbers that show the engine combustion is better with these and not the 2 or 4 prongs (which I failed with).
https://www.autozone.com/external-en...962/505367_0_0

- - - Updated - - -



Looks like you also have oil on the plugs which means you need a new head gasket.. which is cheap and easy to replace. Oil getting into the engine can also cause the HC and NOX to be higher from what ive read.

WOW. Let's see if I've got this straight...

You're saying Wayne should throw a set of incredibly expensive cats at the car, based on no other evidence besides high NOx at low rpm only?
But that after he spends all this money on that GUESS, he should save a few bucks buying cheaper spark plugs because of your anecdotal personal data?
And then he needs to change his HEAD GASKET, because there's oil on his spark plug threads? And changing this head gasket is cheap and easy? Have you ever changed a head gasket ?
And you think injector cleaner is actually capable of correcting spray patterns and flow on 28 year old injectors?

[E36 Em Tree]

WOW. Let's see if I've got this straight...

You're saying Wayne should throw a set of incredibly expensive cats at the car, based on no other evidence besides high NOx at low rpm only?
But that after he spends all this money on that GUESS, he should save a few bucks buying cheaper spark plugs because of your anecdotal personal data?
And then he needs to change his HEAD GASKET, because there's oil on his spark plug threads? And changing this head gasket is cheap and easy? Have you ever changed a head gasket ?
And you think injector cleaner is actually capable of correcting spray patterns and flow on 28 year old injectors?

Well (i thought) obviously starting with the least expensive stuff first like spark plugs, but apparently I need to suggest order of operations. Also, I never said throw the old ones away did I?
Yes, my bad, I meant to say engine valve cover gasket if you're being a dick about my wrong nomenclature.

So.... because I got a "wow" factor based on my comment. Try and chase an evap leak. Test your fuel purge valve under your intake. Change your valve cover gasket when you change plugs to copper 1 prong NGKs. Run injector cleaner on a tank of gas and then change your oil.

$24 for 6 plugs.
$6 for 1 bottle techron injector cleaner.
$35 for 1 valve gasket and if he's taking plugs.
Plus his purge valve .. maybe $150. Another $150 for evap.
Then he can change his CC if all else fails.

But I suggested injector cleaner because obviously it's cheaper and easier than replacing all his injectors and getting them tested. Are you suggesting he just change his injectors instead of trying to run cleaner? Cause I said cleaner cause it's cheaper.

I've had a vacuum leak due to a bad purge valve and gas cap and I didn't even get high NOX. I also did my valve cover gasket, plugs and oil change like many threads suggested. He also said he ripped his car up and down to get the cats warm which also adds to the cats not being as effective. But obviously common sense would say go through the cheaper solutions first before replacing a catalytic converter to a CA legal one. Besides my improper and accidentally nomenclature mix up his costs are less than $300. And most evap stuff I mentioned he can diagnose himself.

And how is it anecdotal when I just said I had smog tests proving it lowered my numbers? You think the machine just magically lowered my numbers when I replaced 2 parts I mentioned above? 3 if you count my previous e36 m3 passing when I changed the cats?

Here's my smog checks Wayne.. I was able to slowly check off issues and get my car registered by going down a mental checklist I got from reading through countless forums on here.

20230215_182815.jpg
20230215_182849.jpg

If Wayne does all the "maintenance" items like cheap plugs, fixing evap issues, and oil change, and then doesn't have to change his CC then cool. Everything I mentioned besides cats are basic maintenance items he should address as a new owner of an e36 anyways. He's clearly got oil on his plugs but it already looks like he has the plugs I mentioned anyways. But majority of the threads for e36 related smog issues say 1 prong V plugs over 2 or 4 prong. Plus many issues are related to evap for the test including purge valve and charcoal canister, plus holes in rubber hoses.

I didn't suggest O2 since someone said that as well and O2s for these cars (4) cost 160ish each plus 9% CA tax. So he's spending a shit ton of money regardless if he's chasing his problems but O2 sensors were probably replaced more recently than anything else I suggested. And guaranteed he's replacing his cats sooner than later anyways.

Wayne if you want help lmk. Done this a bunch of times in California to pass smog. I can name charcoal canister, throttle elbow cracking, vacuum lines cracking, bad gas, bad o2 sensor, bad ignition coil, bad ignition boot, burning oil, EGR. The list goes on but based on what you've said, what I've done, and what I've researched I'm suggesting changing those small items (not the CC yet) and try to see if it lowers anything.

Btw you can title the car with AAA or DMV in person without a smog cert.. you just can't register it.. yet.

[bmwdirtracer]

OR, you can do a smoke test, and fix the intake/ccv leaks, one of which you've already found.

That, or start throwing parts...like the EGR???, for instance?


{Two different test results on two different days, without proven data like ambient temps, engine temps, humidity, etc...Yes, that's anecdotal, sorry. Similarly, "one-time experiences" with one or two cars does not make for a valid scientific sample.}

Step one in diagnosing and fixing an issue which suggests mixture problems is to make sure that the intake system is intact. Thus, a smoke test is absolutely the first step.

Primary O2 sensors are also a maintenance item, at ~90-100k miles; they control the mixture. Post cat sensors do not.

"Injector cleaner" is great, if used regularly. It is absolutely nothing like sending the injectors to RC Injection, where they are tested, ultrasonically cleaned, "blueprinted", and retested (For ~$26 each). Every set of injectors I've sent them for cars of this age have been at least 25% off specs, some as much as 65% off. One dripping or clogged injector will cause horribly erred mixtures in three cylinders. A can of injector cleaner won't even touch this.

And "guaranteed he's replacing his cats sooner than later anyways" ??? This led me to do a quick bit of math. Let's see....I've probably worked on, oh, well over 25,000 cars in my career. And I've probably called for replacing catalytic convertors less than twenty-five times. That's 0.001; one car out of a thousand; one tenth of one per cent.

[E36 Em Tree]

Do a quick search of "e36 M3 didn't pass CA smog" and you'll see how wrong you are. You don't have to follow CA emissions. There are so many threads where people have replaced their cats.

If you're saying O2 sensors are primary maintenance items then so are plugs, leaking valve cover gasket, evap issues (like commonly faulty fuel purge valves), etc. Purge valve can be checked on his own, he's obviously competent enought to change his plugs so he can change 6 more + valve cover gasket kit from fcp for 30bucks.

I threw EGR out there as an example of how many other things could be out there. A vacuum leak will be 1 out of a few things he's going to have to do. Plus you don't know if the previous owner used injector cleaner so why not use 6 dollars and run it in a tank of gas anyways.

A shop in CA is gonna charge him 1 hour of labor for a smoke test. He's found issues himself already and the rest of the stuff is common maintenance stuff. Regardless he's going to need more spark plugs so why not have extra jic?

I'll do the post one better
Read all these and I bet owner will go down all these as a checklist anyway. Literally everything I've told the author is based on forum research and what has worked for people including plugs. I could even say don't pay for the smoke test and try to use carb cleaner first to see if revs change to find the leak.

https://www.google.com/search?q=e36+...h=676&dpr=2.63

Out of 25000 cars how many have come through with smog issues of obd1 cars and how many were e36s. You're not even taking a legit sample size of cars. Most the cars you work on are probably considered smog exempt in CA or aren't considered high polluters needing a STAR test

[bmwdirtracer]

I could even say don't pay for the smoke test and try to use carb cleaner first to see if revs change to find the leak.
I threw EGR out there as an example of how many other things could be out there.

There's no point in carrying this any further.

[E36 Em Tree]

This isn't North Carolina. Hes in California or as most people call it on here Comifornia with strict smog laws. These cars barely pass smog here since they came out. If he was going to take it into a certified SMOG shop for repairs he wouldn't be in the forums asking for DIY help and input. This isn't a car shop he came into.. once again it's the forums.

Has anyone on here even been through a CA SMOG test?

[bmwdirtracer]

Yes, in fact, I have. I've lived in California, twice. And, unlike you, I'm a master technician. Unlike you, I believe in diagnosing the problem, before throwing parts based on anecdotal nonsense.

Spraying flammables isn't a viable way to prove whether or not a BMW has an intake system leak.
And there's no EGR system on this (or most) BMWs.
And his spark plugs only have 3 miles on them, and they should last ~50,000 miles.
And "There are so many threads where people have replaced their cats." is nothing like saying it was necessary.

You can always find stupid answers on some forum, somewhere, but at this particular forum, we have a number of BMW technicians and exceptionally erudite owners, and we try to give answers based on science, not a magic 8-ball.

[E36 Em Tree]

I've troubleshooter my E36 enough to give credible information to this dude wanting to smog his car. And yes you're right his particular car doesn't have an EGR and that's my mistake because I keep forgetting he's an obd1 m3 but the obd2 m3 has one. You guys didn't even offer him anything more than telling him to smoke test it. Thats like one of many issues that it could possibly be. The rest of the issues are obviously due to maintenance related issues if he's fialing smog. Smog is there to make sure the car is combustion properly right.. so he's going to have to do maintenance on his brand new purchase anyways. Not all plugs work well for the S52, it's plagued by cooling issues which could cause high engine Temps and nox, his HC are high probably from umburnt fuel which could be bad plugs, his oil being burnt, the octane booster he ran, the purge valve. I didn't tell him to go change his cats right away. Not sure why you keep going back to that point. I thought that was obviously the longest and most expensive part someone would save for last but looks like you took that one to heart to do first.

And how was my answer saying his O2 reading + high Nox doesn't equal a bad cat? The cat is supposed to collect and break down those gases.. then high hydrocarbons can also mean running rich. Yes it can also mean he's running lean and other items are stochiometric fuel ratio but those issues I told were the most common ones. Like I said there are so many other things that affect smog on this car I didn't even mention. He obviously doesn't have all the tools to do what a "master tech" does. And he hasn't owned 2 m3s for 12 years like I have in CA. Yeah, it's still a bmw but it's still different than other bmws.

And I did tell him to diagnose his engine by blowing in the purge valve no one else seems to have mentioned. Literally a 5 min job to test for vacuum leak. Plus the intake is right there for him to inspect too. He's also going to have to address his oil leak eventually too so not sure why you're knocking on every maintenance item I initially said when that's all PM. Plugs are literally 24 bucks with free shipping from autozone. I'm sure he can afford that and have a back up set just in case. Plus if oil got on the boots of the coilpacks I'm sure they're bad too.

If you lived in CA you know that you don't go to the DMV to smog either and you can still title your car with AAA and DMV in person and not online, but you just can't register it until it passes smog.

And obviously there's stupid answer which is why I didn't tell him to spray cleaner in his intake. Those were all.examples but you're taking everything I'm saying seriously like I was adamant he does it. Super weird.

[328 Power 04]

WTH?
OBD2 M3 does not have an EGR.
It's hard to take your posts seriously if you post such stuff.

[bmwdirtracer]

I never said he should or should not replace the valve cover gasket, because he was in the middle of doing so, in post number 5.
However, so that you know, a leaky valve cover gasket doesn't "let oil into the engine".

This is an S50 engine, not an S52.
While you claimed the car would need 4 oxygen sensors, it only has one.

You'll note that the NOx emissions are the most striking failure item....but only at low rpms - which strongly points to a lean mixture from an intake leak (the most common cause of high NOx), rather than a failed cat or elevated engine temps, which would also cause high NOx in the "higher speed" test.

You can actually buy a smoke machine from EBay now, for less than the price of an hour's labor at a shop in California. My smoke machine was much more expensive, and has been my very best diagnostic tool, besides a scanner, for twenty years. NOT smoke testing a car with mixture/emissions issues, first, is a waste of time and money.

https://www.ebay.com/itm/23482737715...BlBMULbowbjjYQ

And, as Abel has pointed out, there's no EGR on any E36 M3 (or on the majority of BMWs).

I never said Wayne's cats were okay, or that there weren't other possible issues besides intake leaks, but intake leaks alone could easily be the cause of his failure, and are the easiest thing to address.

You've said "Your NOx is most likely due to your cats going out", and "And guaranteed he's replacing his cats sooner than later anyways"...so yes, that's why I "keep going back to this".

[E36 Em Tree]

WTH?
OBD2 M3 does not have an EGR.
It's hard to take your posts seriously if you post such stuff.

Yeah super hard to take someone serious when they make a mistake like that.

That wasn't even my point for his SMOG issues. I mentioned it as another point as a SAP/EGR issue. Yes my bad for thinking an M3 had an EGR through my 100s of posts I read to diagnose my own smog issues. I obviously didn't get that far into the car because I worked from the little/cheap and common things first before getting to air injection and cats.

You guys are doing more arguing with me than trying to even help anyone tbh. Bunch of little keyboard warriors you guys are defending each other.

[328 Power 04]

It's not the mistake, but more of a lack of understanding/knowledge of what these systems do. SAP and EGR are not the same. You sure argue a lot despite this. Good job on crapping on the OP's thread, although I doubt he'll be back.
The irony is that you come here to argue and call us keyboard warriors. Grow up, and good luck.

[E36 Em Tree]

I didn't even say a SAP or EGR were the same.. I used the backslash as an "or" and those were once again examples. You guys take everything so literally.

I offered more things for him to look out for than you did tech expert. If you wanna help OP then just ignore me and I'll do the same.

Good luck with what? Haha. You guys literally try and tear my post apart and say I'm coming here to argue? I comment and one of you guys has something to say about how I'm wrong because you took something out of context or literally.

You sure haven't issues any insight to this post so I'm crapping on the OPs thread? Okay. I wasn't even talking to you before you quoted me.

Bye

[bmwdirtracer]

This is the mechanical forum, and yes, we try very hard to be accurate here.

We don't call a valve cover gasket a head gasket, nor do we tell people that a leaky VCG lets oil into the engine and raises their HC.
We don't tell people their car uses 4 O2 sensors, when it only has one.
We don't call an S50 an S52.
We don't point to an EGR system or an SAP system, when the car has neither one.
We don't tell people that high NOx, at low speeds only, indicates bad cats, when it's most likely an intake leak.
We don't tell people that they'll "most likely need cats sooner rather than later", for no reason at all.
We don't tell people to replace 3 mile old spark plugs with the same things.
We don't say "I could even say don't pay for the smoke test and try to use carb cleaner first to see if revs change to find the leak."
We don't tell people to replace cats because "there are so many threads where people have replaced their cats".
I'm sure I could find more, but I'm tired of wading through all the misinformation.


If you don't want people to "tear apart your posts", then don't post crap...or post it somewhere nobody knows the difference.