Can I completely remove the wiring for unused emissions stuff from my engine harness?

[points]

About to start a 4.2 swap in my A4 and I will not be using the SAI and rear 02s for sure since this is a full time track car. Can I remove the wiring from the engine harness without causing issues with the ECU assuming its coded out when I do the S6 ECU flash? I'd like to clean up and wrap the harness with good heat protection while the motor is out and simplifying it would be pretty nice since the motor tends to go in and out after each race for clutch work and what not and the less dangling connectors in the engine bay the better. It's already been done with all the extra interior wiring and that wasn't a problem but since good engine harnesses are hard to come by I don't want to rip it apart and then need to get a new one.

[Blazius]

You can , if they are taken care of in the software.

[points]

thanks!

[xdewaynex]

Definitely but like mentioned, needs to be tuned out if you don't want lights on. I removed all the wiring for emissions, abs, and several others from mine but I'm also running standalone.

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[A1 A2 German]

So I may botch the explanation but the idea is the same.

I'm running standalone, but at times switch to a coded out, flashed, oem ecu, and I was informed by not only the coder (but other coders) that you're going to want to leave the tangible unit(s) you're coding out electrically plugged in. Please note, electrically plugged in (only), they do not need to be tanglably hooked up per hoses, etc. There's two things going on, the ecu coding something out of the system is like coding out the signal, like deleting or replacing the signal. However! The unit still draws power and/or resentence and the ecu is looking for that, so when you toss your N75 valve in not only sees a lack of signal but lack of draw and can trigger a dtc. So I keep everything in a bag, when I swap to oem software, even though coded out, I take ~60 seconds to plug in my N75 valve, evap purge valve, etc.

Now, the one exception is the SAI, once coded out that plug you should be able to just leave blank...but I also believe because that's just an electrical motor where a dummy 12v signal is sent to it...aka, the ecu is not measuring for resistance. There's a couple tricks, you can get an entire A4 B5 resistor pack, they are little low profile resistor Bosch block off plugs that go on everything you want to delete (like an entire B5 kit is like $49). That way you can toss all the little components you're deleting with little 1oz cap off plugs. Or what I did is when I did my harness and I took all the emissions and N75 stuff (wiring) all the back into the ecu box (also shortened the wires) and when I pop in my flashed ecu I can plug things in there and cleaner however might just get the resistor plugs as low profile.

[points]

that's what i was more curious about. I might just de-pin them from the ecu harness before I remove them completely and see what happens. That way I can plug them back in if need be. Don't care about getting codes or lights for them as long as the car runs fine.

[Blazius]

Trust me. You can completely eliminitate wiring if everything is handled in software, its as if the car was never supplied with it. Resistors are from 15 years ago when people didnt know how to handle this ecu.

PROVIDED, you can do this in software, and you can with the 4.2s.