I have a rebuilt s5 motor, ecu, and emission harness that I would like to place in my s4. What is the procedure for changing the connectors that are on the harness and plug into a harness under the dash. I also need to know about the third connector into the ecu. I really don't even know were to begin since there is a difference in wire amounts on each plug.

 

it will be 20x easier to get a s4 ecu and wireharness...they are cheap and easy to find.

if you really want to do this you are gonna have to look at the fsm/wiring diagrams and repin everything.

 

it would be great if someone has made a write up for this electrical swap i have the same problem and dont know where to begin either i know you can leave the s4 ecu and harness and swap over all the parts from your s4 to your s5 motor but does anyone know how to put the s5 harness and ecu in the s4 and change the dash wires?

once i figure this out i should start making my own harnesses for this swap id make a killing

 

no

 

Will I wanted to keep the ecu so so I would have working vdi and 5th n 6th ports. I guess I will pull out my dash and start replacing harnesses with ones from a series 5.

 

scratch that idea. For the same amount of money and work it would be a waste to not just put in a used standalone.
650 to get rtek chipp and handheld
100 for selling great condition harness, multiple sensors and afm.
I should be able to find a used lt8 microtec for around 800.00
by the way the car is a manual swap
Do you think between a good tune and a medium street port I could reach 190whp.