Smog time again

[DavidE9]

Hello,
The issue of not having a check engine light is really an issue for most places I've tried. Encinitas Smog Center hasnt had a problem with the cert, but they are booked up. Can anyone recommend a shop in San Diego, Orange County, or LA ?

Thanks

[MLastovo]

Convoy SMOG.
Speak to Yaro but if he is not there his son and/or employee will take care of you.
I doubt he will know my name if you mention it but we have known each other for 15+ years. Tell him that I was just there last week (the 10th ~11:30AM) with the e39 AND that I am the guy who had the nice blue e28 AND the guy with the baby blue, rusty 1980 Datsun pickup. He'll remember.

https://www.convoysmog.com/

D.

[DavidE9]

Thank you. There doesnt seem to be a list of SMOG shops on here. I thought Id start a post in Tech FAQ per the instructions, but I dont seem to have permissions to do so.

SMOG shops that can handle an E28:

San Diego shops:
https://www.convoysmog.com/
https://encinitassmogcenter.com/

[MLastovo]

San Diego shops:
https://www.convoysmog.com/
https://encinitassmogcenter.com/
https://wentworthautomotive.net/ - Speak to Justin.

[DavidE9]

Well, that didnt go well.

NO > 2,000 PPM @ 25 MPH

https://share.icloud.com/photos/0e2pHwt ... NVm7UBJhKA

[Mike W.]

I thought Id start a post in Tech FAQ per the instructions, but I dont seem to have permissions to do so.

Procedure is, start with a title of FAQ, post in Tech Talk, see if it gains traction or PM a Beamter. Once it's deamed "finished" you can request it be moved to the FAQ.

Well, that didnt go well.

NO > 2,000 PPM @ 25 MPH

https://share.icloud.com/photos/0e2pHwt ... NVm7UBJhKA

Oh shit, that's not good at all. Sounds waaaaaaaaay lean. What's the O2 say?

[DavidE9]

Smog FAQ started, I think.

Im going to get a multimeter on it later today. Maybe I just have a vacuum leak somewhere. I did remove and clean the vacuum lines a month ago so might just be me making a mistake ---it usually is. Occam had me in mind.

[Blue Shadow]

This is mostly a California issue. They require original equipment or CARB approved parts and if they aren't there, fail. Then they want to go by the book that lists some of our late production cars as having CEL when they don't and being 35 year old cars, CARB is not going to update that information. So finding a knowledgeable shop is key.

Getting this list together might help the California E28ers and they should post back what shops they use for smog.

Me, I got an antique plate here in PA, no more smog. And did you see that part a single plate. No front plates in PA. Although I have a ticket for a missing front plate in another state dating to a week before I moved to PA. I'm thinking I can avoid that one.

[MLastovo]

Sad to hear that the car failed the test. 15+ years ago my iS failed as a gross polluter and after R&R of the plugs and a valve adjustment it never failed again. YMMV.

I had dinner with Carl and Amy Sunday night and asked him where he is bringing cars and he said Yaro.

Good luck,
D.

[DavidE9]

Results from smog test last year show NO = 256 ppm @ 25 mph

Testing the oxy sensor with my multimeter.

Car warming up:
bounces between 3 millivolts.and 4 millivolts.'
https://share.icloud.com/photos/0c8iYhO ... OUv3XdNFlQ

Car at temp:
solid 5 millivolts
Dip stick out causes fluctuation between 4, 5, 6 millivolts
https://share.icloud.com/photos/0c8fI9n ... E9GPQkGKcA

If I read Bentley correctly, the oxygen sensor is fine.

[Mike W.]

No, not at all. It should be bouncing between at a minimum of .2 to .8 volts. Probably closer to zero and .9 volts. That's tenths of a volt, not thousandths. It's probably barely running and completely explains your sky high Nox readings. But that's kind of good, it suggests such a large vacuum leak it should be easy to find.

[Karl Grau]

Not to thread hijack but does anyone have any insight on these results from two years apart on the M5?



The only difference between the first results and the 2nd results two years later was brand new injectors and super high octane fuel.
I'm thinking I should just put the old injectors back in and skip the high octane fuel.

[Mike W.]

Not to thread hijack but does anyone have any insight on these results from two years apart on the M5?

The only difference between the first results and the 2nd results two years later was brand new injectors and super high octane fuel.
I'm thinking I should just put the old injectors back in and skip the high octane fuel.

I think the gas is ok, but the injectors probably are the problem. It's running pig rich at 15MPH, odd since the RPM is so similar, although the load is somewhat different. Unless the smog guy didn't like you and tanked it on purpose, but that would probably show up on Nox more. I'd check the O2 sensor first, but unless you've got a spark plug cable off, it sure points to the injectors. Stock ones?

[tschultz]

Did you test with your cat all warmed up and toasty? I have heard injectors get older and clog up slowly and flow less. Also o2 sensors tend to run more lean as they get older-- not sure how true that it, but could be pushing things lean...


Some good info here on emissions: http://bigcoupe.com/phpBB2/viewtopic.php?t=19661

No cat convertor


With a catalytic converter, the concentrations drop down significantly in the range near stoich.


Obviously in the small range around the shaded part, the emissions are very low. So, the trick to passing smog is a) to get the air fuel ration in that region, and b) to understand why it isn't in that region (assuming you are not passing).

Causes of rich running can include:
- Bad plugs
- Mis set AFM
- Excessive fuel pressure
- Bad coolant sensor (the ECU senses the temp and richens the mix when the car is cold), or bad wiring between the coolant sensor and the ECU
- Bad air temp sensor in the AFM (the ECU richens the mix when the air is cold, because cold air is denser, so it takes more gas to maintain the 14.72:1 air fuel ratio

Causes of lean running can include:
- vacuum leaks (oil cap, valve cover, dip stick seal, breather hose between the throttle body and the valve cover (basically almost inaccessible), throttle body bellows leaks, manifold leaks, etc)
- Mis Set AFM
- Low fuel pressure
- Leaky valves

Verify you have no vacuum leaks causing air to enter the engine when it shouldn't be.

If all three levels are elevated, it could be something related to the CAT. I'd verify your CTS is good and not causing it to run too rich and overheat the cat. Next, check the output voltage of the O2 sensor to verify if the signal is staying close to stoich or rich/lean in similar driving conditions if it is rich or lean running). If the cat wasn't running hot enough, all 3 concentrations would be elevated...

[DavidE9]

I think I will try this DIY smoke machine to look for air leaks. Should I attach this to one of the vacuum ports under the intake, or does it make sense to try to ingest the smoke further forward closer to the air filter ? Thoughts ?

https://www.youtube.com/watch?v=VvcFGzAyaXE

[Mike W.]

It's got to be after the butterfly, otherwise no vacuum.

[DavidE9]

Replaced the O2 sensor, the breather line that connects under the ICV (had a crack) and reconnected the loose vacuum line for the cabin and I passed SMOG today.

New numbers:
NO
234 ppm @ 15 mph
137 ppm @ 25 mph

I think these O2 numbers are what I should see:
https://share.icloud.com/photos/0943KcK ... d0fWFIHcWg

Thank you, Mike and Darrin.

[MLastovo]

Thank you, Mike and Darrin.

My pleasure.
Did I not read in one of your posts that when you pulled the dipstick there was no change in how the engine ran? I swear that info was there during one of my reads.

If you did do that and there was no change in engine operation it was a good indicator that there was a pretty significant vacuum leak somewhere. A properly tuned M30 will at worst run very poorly and at best die when the dipstick is unseated. That result would've lead you down the path that appears to have ultimately been the (main) cause of the failure.

r/
D.

[Shawn D.]

Smog FAQ started, I think.

Are you referring to this discussion? It'll have to be distilled into a single post or a few posts, not a bunch of back-and-forth and tangentially-related posts.

Also, see this: https://www.mye28.com/viewtopic.php?f=9&t=17321

[DavidE9]

No, this is what I posted in an attempt to create a FAQ:

https://www.mye28.com/viewtopic.php?f=3 ... 6#p1534906

[Shawn D.]

No, this is what I posted in an attempt to create a FAQ:

https://www.mye28.com/viewtopic.php?f=3 ... 6#p1534906

Thats a good start! Please reformat it as shown in the link I posted above.