Best way to run catted section 1 for CA smog ?

[bavarian3]

Check my journal. Basically a euro car setup with working post cat 02s. Egt isn't needed or checked by CA smog so do whatever you want (I don't bother).

Thanks for the clarification on the EGT.

I did actually look at your journal and was curious on a couple things:

-If you had or followed a DIY anywhere on what seems like your o2 rigging to extend them to cats?
-If you still kept your SAP deleted after adding HJS cats?

[Tbonem3]

The trick to extend the post car o2 harnesses is to cut the rubber sleeve a little, pull out the extra o2 wiring, and then run it behind the engine, under the airbox, along the driver side of the engine/ tranny bellhousing and along the driveshaft wall, over the trans brace, then cut a small hole in the sect 1/2 tunnel heatshield to connect to the sensors at the end of your catted sect 1.

I choose to delete cold start (sap), and physically block off egr with a euro plate (genuine bmw part). You can or not, doesn't affect anything (though you'll have to reinstall for smog).

Here's a pic of everything I replace to pass smog:

[bavarian3]

The trick to extend the post car o2 harnesses is to cut the rubber sleeve a little, pull out the extra o2 wiring, and then run it behind the engine, under the airbox, along the driver side of the engine/ tranny bellhousing and along the driveshaft wall, over the trans brace, then cut a small hole in the sect 1/2 tunnel heatshield to connect to the sensors at the end of your catted sect 1.

I choose to delete cold start (sap), and physically block off egr with a euro plate (genuine bmw part). You can or not, doesn't affect anything (though you'll have to reinstall for smog).

Here's a pic of everything I replace to pass smog:

I read about the extra length wire in the sleeve, but it looked like you did things a little differently? Not clear.

And you have no issues with intermittent check engine lights? how about you zzyzx85

[zzyzx85]

I didn't do the extension myself so I can't really tell you how it was done. I had my mechanic do it when he installed the euro headers and section 1. It looked like he just unwound the harness that was under the valve cover beauty cover and routed it back.

I also run a CSL box the majority of the time with a tuned HP DME.

When it comes time to smog, I swap out the DME for the stock one and put the stock airbox back on. I then do the whole readiness monitor cycle to get everything "ready" and it passes flawlessly.

Besides changing out the old O2 sensors that were giving me a code, it's never given me any CELs.

[jpy1980]

I didn't do the extension myself so I can't really tell you how it was done. I had my mechanic do it when he installed the euro headers and section 1. It looked like he just unwound the harness that was under the valve cover beauty cover and routed it back.

I also run a CSL box the majority of the time with a tuned HP DME.

When it comes time to smog, I swap out the DME for the stock one and put the stock airbox back on. I then do the whole readiness monitor cycle to get everything "ready" and it passes flawlessly.

Besides changing out the old O2 sensors that were giving me a code, it's never given me any CELs.

Couple of questions:

1. what is the readiness monitor cycle? How do you perform it after a dme swap / stock time flash?

2. you have euro headers and section 1 cats and pass smog. Would smog be passed with any careless header with any section 1 with cats?

[Tbonem3]

Couple of questions:

1. what is the readiness monitor cycle? How do you perform it after a dme swap / stock time flash?

2. you have euro headers and section 1 cats and pass smog. Would smog be passed with any careless header with any section 1 with cats?

1. The ecu performs checks each cycle (start to stop). It happens all the time, but there are operating conditions that must exist for the cycle to complete. For example to set the monitor ready for cold start the engine must be cold, and you must not touch the gas pedal for a minute or 2 while sap warms up the cats.

2. Yes. The main issue is quality of cats. Must be good enough to satisfy the o2 sensors (post cat). I've passed smog with ebay, ap euro and supersprint headers and eurocats, ssv1 hjs and magnaflow 200 cell into 2.5' ss v1 decat pipes.

[Tbonem3]

I read about the extra length wire in the sleeve, but it looked like you did things a little differently? Not clear.

And you have no issues with intermittent check engine lights? how about you zzyzx85

No issues. I didn't extend the wiring with more wire and splices, just routed the existing harness in an efficient way to reach all the way to the o2s at the end of sect 1.

I seem to remember a thread with some pics of what to do. I can't take pics for you now as it's all covered up.

[jpy1980]

1. The ecu performs checks each cycle (start to stop). It happens all the time, but there are operating conditions that must exist for the cycle to complete. For example to set the monitor ready for cold start the engine must be cold, and you must not touch the gas pedal for a minute or 2 while sap warms up the cats.

2. Yes. The main issue is quality of cats. Must be good enough to satisfy the o2 sensors (post cat). I've passed smog with ebay, ap euro and supersprint headers and eurocats, ssv1 hjs and magnaflow 200 cell into 2.5' ss v1 decat pipes.

Thank you so much for the response appreciate it!

[heinzboehmer]

I read about the extra length wire in the sleeve, but it looked like you did things a little differently? Not clear.

And you have no issues with intermittent check engine lights? how about you zzyzx85

You can also do it without cutting anything: https://nam3forum.com/forums/forum/m...221#post131221

[bavarian3]

You can also do it without cutting anything: https://nam3forum.com/forums/forum/m...ge3#post131221

Is this linked to the right page?

[heinzboehmer]

Is this linked to the right page?

I think so? Recopied the link just in case.

Post 110 in that thread shows how I did it

[bavarian3]

I think so? Recopied the link just in case.

Post 110 in that thread shows how I did it

now the link works(other link sent me to oil filler caps on pg 3, lol) , thanks =) will read through this.

[L0okitzRaj]

You can also just code out the rear o2 sensors using Martyn's tool. It'll still pass, as it defaults the sensors to Ready. That way you can install your cats however you want, no need to reroute wiring.

I'm running no cats and have passed smog on two separate occasions in LA.

[bavarian3]

You can also just code out the rear o2 sensors using Martyn's tool. It'll still pass, as it defaults the sensors to Ready. That way you can install your cats however you want, no need to reroute wiring.

I'm running no cats and have passed smog on two separate occasions in LA.

Thanks a ton for chiming in with this. If this is the case perhaps I'll just start with that route before modifying anything wiring wise.

That then leaves the question if there's any downside at all to deleting post-cat o2's?

[L0okitzRaj]

Post cat o2 sensors are only for monitoring cat efficiency. So no downsides.