Audi 4000 Turbo quattro Conversion
This page under construction. Take it with a grain or two of salt. I am still proving out the information found here.
Just because something is blank on this page does not mean it is unimportant. It means I have not gotten off my butt and either figured it out or bothered to post it. If anyone is currently working on a similar project and has questions please email me. I will try and help.
The electrical portion of a conversion is an area that seems to scare a lot of people. I see it as a nice break from the dirty wrench spinning and knuckle busting of the rest of the conversion. I started by sitting down with the turbo wiring harness and my 5000 Bentley manual. I took some masking tape and put a number on each connection. Then I went through and made a key telling what each connector does. I have posted it below. It may or may not be helpful to someone else as the numbering is random. With all references to wires the first color is the major color and the second is the stripe or ring. The number in () is the metric size.
Out with the Old
The first thing I did was get rid of the wiring I would not need. Since I still keeping all my accessories like A/C and cruise control the engine harness is the only thing that has to go. Since the A/C compressor will have to move to the other side of the engine (more on this later) the existing engine bay harness will have to be changed somewhat.
The JT engine computer is connected to the side of the glove box. Getting the harness out would probably be rather tricky if you don't take out the A/C evaporator first. I had already had my system discharged since I knew I would have to move the compressor. Plus I needed to change out the heater core anyway. This made it easier to deal with removal of the harness. Still there are 10 wires that branch off of the computer harness and head to the drivers side of the dash. Their functions and required connection after conversion are outlined below.
Branch of JT ECU harness that heads to drivers side of dashboard
These are in no particular order. Pin # is found by holding the ECU connector with the long row on top and going left to right.
List of connectors for KH engine harness
Connector numbers are made up by me and are in no particular order. This is still a work in progress so there is a good deal of missing information.
Changes on Engine
The cold start valve is run by the computer on this car. I had to supply switched power to the valve and grounded through pin 1 on ECU. Make sure this power is on while the engine is cranking. Since this engine did not use a heated O2 sensor I used this circuit. I also used it to power the differential pressure regulator that is mounted on the side of the block. The JT motor did not have one of these.
The idle stabilizer on the KH motor is 2 wire instead of 3 wire. I just used the stabilizer from the KH motor. The KH motor I had was from a front drive car I believe. It did not have an oil temperature sender mounted on the oil pump. I transferred mine over from the JT motor.
As it stands right now the car is back as my daily driver, but not everything is straightened out. For now I have a headlight relay in place of my fuel pump relay. This means the pump runs whenever the key is in the on position. Not the safest, but I now own a KH relay. It requires some work to get it wired in, but I will outline that once I get to it.
My trip computer does not work which does not surprise me as I have not tried to wire it back up yet. My cruise control does not work - I have done some troubleshooting with no luck so far. The oil pressure warning system is not working right and has therefore been removed for now. Yes this is very scary, but I have not had a chance to work on this yet. Worst of all my power door locks have decided to stop working.
I ended up adding the old JT engine temperature sender in the hole at the back side of the head where the vacuum switch goes on the KH. I had never hooked up the vacuum switch so it was not doing anything. Now I have a working temperature gauge and over-heat warning system.