[bobbby]

Need to pass smog soon. My car is tuned with MHD stage 1 and xHP stage 3. Just wondering if anyone with similar mods passed the newish smog test that also checks for ECU tunes.

Can I just run stage 0 mhd or do I have to flash back to stock? Also do I have to flash my transmission back to stock?

TIA

[ghostENVY]

I'm due for a smog check in the next couple of months in CA.
Honestly just from a programming perspective, I feel the checksum of the original firmware will be checked against, therefore I believe stage 0 should theoretically still fail, but what do I know.
I'm planning going back to the stock firmware and removing my charge pipe/tial and also referring PCV and Oil catch cans.

[R3dLeader]

Flash back to stock with MHD and put your cats back on.

[bobbby]

As an update here, flashed back to stock completely, removing MHD. Drove around to get the monitors into complete and was able to pass smog today.

Only mods are MHD, xHP (flashed also back to stock, leaving xHP still installed on car), aftermarket chargepipe/fmic

Now back to reinstall MHD! Good til 2025

[2one3E90]

Originally Posted by bobbby

As an update here, flashed back to stock completely, removing MHD. Drove around to get the monitors into complete and was able to pass smog today.

Only mods are MHD, xHP (flashed also back to stock, leaving xHP still installed on car), aftermarket chargepipe/fmic

Now back to reinstall MHD! Good til 2025

stock cats also?

[SAADTHESAV]

Yeah I'm trying to sell my '09 3 series and it's not registered because I can't pass smog with no secondary cats

So I need to find a cost effective way to restore my secondary cats and pass smog lol

[StradaRedlands]

Is leaving xHP active/on fine for passing CA smog?

[bobbby]

Originally Posted by 2one3E90

stock cats also?

Originally Posted by bobbby

As an update here, flashed back to stock completely, removing MHD. Drove around to get the monitors into complete and was able to pass smog today.

Only mods are MHD, xHP (flashed also back to stock, leaving xHP still installed on car), aftermarket chargepipe/fmic

Now back to reinstall MHD! Good til 2025

Yes Stock cats

[bobbby]

Originally Posted by StradaRedlands

Is leaving xHP active/on fine for passing CA smog?

I left it on, but put it to stock tune

[Ion619]

I'm due soon too... been thru this many times with my 09 E90...

Gotta put back stock cats and completely uninstall MHD...

For some reason, flashing back to 0 isn't sufficient enough...

The "monitors" will not "complete" after driving many miles...

Good Luck!

[Mseg]

Originally Posted by SAADTHESAV

Yeah I'm trying to sell my '09 3 series and it's not registered because I can't pass smog with no secondary cats

So I need to find a cost effective way to restore my secondary cats and pass smog lol

I went through the same thing earlier this year. To fix it, I bought CARB approved secondary cats for my 325i, Walker Exhaust CalCat Carb 84205 Universal Catalytic Converter, through Amazon. They have an CARB EO stamped on them and they're cheap. I then paid an exhaust shop to add them back. The Smog Tech looked at them and put the EO in his computer and passed me.

[SAADTHESAV]

Originally Posted by Mseg

I went through the same thing earlier this year. To fix it, I bought CARB approved secondary cats for my 325i, Walker Exhaust CalCat Carb 84205 Universal Catalytic Converter, through Amazon. They have an CARB EO stamped on them and they're cheap. I then paid an exhaust shop to add them back. The Smog Tech looked at them and put the EO in his computer and passed me.

Wow this is clutch. I'm guessing depending on your exhaust they might have to weld a part on? Or is it usually as simple as cutting the pipes where the catalytic converter is and then installing the Walker exhaust catalytic converter fromm Amazon?

[Mseg]

Originally Posted by SAADTHESAV

Wow this is clutch. I'm guessing depending on your exhaust they might have to weld a part on? Or is it usually as simple as cutting the pipes where the catalytic converter is and then installing the Walker exhaust catalytic converter fromm Amazon?

Sorry for not getting back to you sooner. The exhaust shop had to cut my piping and weld the cats back on. I had changed my exhaust in that area to a single pipe, and they needed to change that section back to double pipe to put the new cats on. It was a little over $400 for install.

[blackx1x35]

Originally Posted by bobbby

As an update here, flashed back to stock completely, removing MHD. Drove around to get the monitors into complete and was able to pass smog today.

Only mods are MHD, xHP (flashed also back to stock, leaving xHP still installed on car), aftermarket chargepipe/fmic

Now back to reinstall MHD! Good til 2025

Hello, just moved to the state and looking to get my car registered. When I originally installed MHD, I had to remove the DME and send it off to a shop to flash on a bench. Did you do the same process? I am wondering if I will have any issue re-installing MHD.

I am aware you no longer have to bench flash to install MHD, but at the time if you removed MHD, you had to redo the bench flash. I am hoping someone can confirm that I will not have to do this if I want to re-install MHD.

Thank you.

[BMWdmk]

Flash to stock (no questions asked you must do this)
Put c. converters on
Don't have codes that trigger check engine
Check Monitors after xx miles to makes sure everything reads complete
(options for monitors is ready, not ready, incomplete)
Everything needs to be complete/not available. Evap monitor can be incomplete
if you get fuel pump plausibility code dont clear. common shadow code is fine.
permanent codes take time to clear dont jump the gun. get mopnitors ready.

follow these parameters and your setup for success except for visual inspection. Google that one if needed