4.2 V8 Swap Wiring in a Prefacelift Car

[Cactus Avant]

Hey guys, for context, I have a prefacelift A4 avant with an AEB and a facelift avant with an ART 4.2 already swapped into it. I bought the V8 swapped avant because it already had all the parts I need for the V8 swap and I could just easily swap everything over to my avant. I have countless hours into researching and talking with people about the swap, so I know what I am getting into, what I need, etc. Wiring is the only thing that is getting in my way at the moment. Of course, wiring the body harness from AEB to the ART is not a popular since its not nearly as straight forward as AWM to ART. I have seen a couple prefacelift cars that have been rewired for the 4.2, but am skeptical if its the right way to do things. I have mapped out the majority of the wiring from AEB to ART, but there is still a lot of wiring that either doesn't match up, or is missing on the AEB or ART side. So I have a couple questions.

1) Has anyone successfully swapped an AEB car with an ART or similar 4.2 with no major issues/no loss of functionality in anything? If so, if anyone has a wiring diagram, I would be willing to pay you for it.

2) Has anyone ever swapped the entire wiring harness from a facelift car into a prefacelift car? Was it worth it? Did you lose any functionality or run into any compatibility issues? (I do have a facelift center console in the car already and will be installing drive-by-wire pedals and facelift gauge cluster, so I am not worried about adapting those.) This is the other option instead of rewiring the car because I already have the entire harness.

I am sort of leaning towards swapping harnesses, rather than trying to rewire the AEB harness just because I know it'll work with the ART and I shouldn't lose any functionality that I am aware of currently. I want to do this right the first time. If anyone has any other tips or input on this wiring issue, it would be greatly appreciated! Thanks!

Picture of cars

P1040068 by Spencer Kohli, on Flickr

[RENOxDECEPTION]

Check out my swap thread.

https://www.audizine.com/forum/showt...-Update-Thread

Not AEB, but AHA to ART, similarities should be close.

Don't do the entire interior harness, I've heard the window logic is weird after or they don't work.

Only thing that I don't have working are reverse lights and cruise control, but I know how to fix both, just too lazy.

[Cactus Avant]

Check out my swap thread.

https://www.audizine.com/forum/showt...-Update-Thread

Not AEB, but AHA to ART, similarities should be close.

Don't do the entire interior harness, I've heard the window logic is weird after or they don't work.

Only thing that I don't have working are reverse lights and cruise control, but I know how to fix both, just too lazy.

So I have been following your thread pretty closely, and thats actually how I've figured out all my wiring thus far. It's been super helpful, but the spread sheet has some missing information and a couple things I am worried about, like the crash signal and a couple of the connections that have the "revision needed" notes attached to them. I haven't been able to figure those out yet. I would be willing to pay for help on wiring. I really want to make sure I have everything working correctly, especially the crash signal/airbag situation. Have you figured any of that out yet? My big issue right now is that this is my only car (apart from the V8 parts car) and I am graduating and starting a new job soon, so I only have less than a month to complete the swap and make sure everything is all worked out. Thats why I was leaning towards the full harness swap, just because I can be confident everything would work correctly. I could swap the window motors (or whatever the issue is) from the facelift car, but thats a lot of work. That being said, rewiring would be MUCH easier and take a lot less time. I'm just kind of stuck right now.

Thanks so much for any and all help by the way.

[RENOxDECEPTION]

As far as I'm aware, the crash signal on the ecu kills the engine and fuel pump and turns on the hazard lights. I had it coded out by my tuner, never found any corresponding wires on the body side that could work.

[Blazius]

As far as I'm aware, the crash signal on the ecu kills the engine and fuel pump and turns on the hazard lights. I had it coded out by my tuner, never found any corresponding wires on the body side that could work.

Correct. Its an important safety feature, you should not mess around with stuff like that IMO( as in coding/disabling it).

[Pumpkinslap]

i was reading into the thread reno posted and decided its the way im going to go with my 99 laser red avant with an aeb set up in it currently that i just bought, although i wont be touching it for a while as im about to cage, 18z caliper swap and gt2860r swap my 1.8t track car lol but ill probably have someone code out the crash signal as well as i wont be driving the car very often anyways, i currently have an art 4.2 i got for free, the only issue with the motor is the guy bought a used wrecking yard motor to swap a single head with his car that had broken the timing belt, but i will probably go pick up an a6 with a bad auto trans. i will be 4.2 swapping, manual v6 gearbox with a transmission cooler, rear diff cooler, and probably oil cooler, and a custom tow hitch welded on the back to tow my b5 a4 track car. thinking about having a longer 4th and 5th gear put in the gearbox though as i will be using this to tow.