To start, a shout out to presslab, he really helped me worked through alot of my problems, thanks dude!
A while ago I was browsing through this forum, and I came across this awesome thread about building paddle shifters for the 4EAT. Here's the link:
This was my inspiration. So about the beginning of February I PM'ed presslab to see what really needed to be done and if this was really possible for me to do.
I guess I should also give a little background on myself before going any farther. Right now I am training to become a IBM Mainframe systems programmer, I have modded xboxes and other SOC (system on a chip) devices including routers, and I have a good background working with computer systems in general. So this whole car thing is new to me, but not electronics. So with that said...
After talking with presslab, I came up with a list of things that needed to happen so that I could get paddle shifters in my loyale. Here's the list:
1. Get TCU
2. Build simple cable to interface with TCU
3. Download original TCU ROM using the cable that I just built and the linux software
4. Compare original TCU ROM Code to new modified ROM code to check for differences to make sure the ROM is compatible and modify any settings
5. Install DIP 28 socket onto TCU PCB
6. Burn new ROM image onto new EEPROM
7. Install new EEPROM into the new DIP socket on the TCU, and disable the original ROM
8. Splice in new plugs into exsisting TCU harness for the new TCU, but keeping the old as a backup
9. Modify the RPM signal going to the new TCU via the new harness. Use a 1k resistor and place it inline from the ECU to the TCU.
On the TCU input install a 4.7V zener diode after the resistor with the cathode on the TCU input and the anode to ground.
10. Build the DCCD switch using a six position rotary switch and wire in some 1N4001 diodes in a series between each pole. The FWD switch pole is attached to ground and the common is attached to the atmospheric sensor input.
11. Build the paddle shifter assembly and install it
With such a short list, it should take me no time to do it all
Needless to say I have spent ALOT of hours just researching and trying to figure out how all this works, and I just got it working today, a month and a half after I started. So this project isn't for the weak hearted, that's for sure!
Personally I don't want to modify something in my car, especially anything having to do with the transmission, unless I honestly can understand what has been modified, how it was modified, and why it was modified. Once I can figure all that out, I will feel much more comfortable installing this into my car. So I set out learning assembly code for the Motorola 68CH11 processor.
Lucky for me I am already somewhat comfortable in a low level machine language due to my training on the Mainframe, so picking up the assembly wasn't that hard. It wasn't easy, but not that hard. The hardest part is knowing how to read a reference manual Man that crap can put you to sleep!
Anyways, once I had figured out the jist of what was going on in the ROM, I set out on getting a TCU that had the same part number has presslabs. Once I found that, I needed to get the harness for the TCU, since the TCU I bought didn't come with the wiring harness. Wiring harness in hand, I set out to wire it up. Here's my thread on the wiring harness:
I broke this whole process up so that each step I did was more easily searchable, and more organized. Also these posts have a bunch of pics in them, so beware!
Read through that thread to see the problems I had with that and how I solved them.
Once it was wired in, I then had another problem, the AWD didn't work. I had a fried transistor on the TCU board that I had to replace. Here's my thread on how I fixed that:
After all the hassles and trouble shooting, trails and tribulations, I was finally able to install the moddified ROM onto the EJ TCU and got it working!
Granted I skip a few steps along the way... I had a buddy of mine burn the ROM image for me, so that was already done. I ordered the cable that I need to interface with the TCU, but I am still working on getting the tcuscan software to work for me :-\ I just gave up and moved on. I figured that if it didn't work with the new ROM, then I would have to figure out tcuscan. Since the modified ROM worked, I am not in a hurry to fool around with tcuscan. I will in the future, but for now, it can wait. With that, I have also not downloaded the stock ROM to verify against presslab's ROM, but since it his ROM worked in my TCU, I can assume that the ROM is the same.
Here's some pics of adding the new socket on the board, and with the new ROM on the board:
Here's some "action" shots, or something like that...
You can see where I started, and how my soldering skills got better as I went First time I have ever tried doing anything like this. Good times
So in order to get the DIP socket to work, you have to move a resistor...
You have to move it from 421 to 422. The "000" on the resistor means 0 ohms, so you can just use a piece of wire as well, which is what I ended up doing, since that resistor is a huge PITA to move. I am going to install a switch so that I can flip between the two ROM's whenever I want. This way it makes this mod a little more reversible. To a point anyways
At this point since the TCU is functioning "normally" in my car, I am ready to start running more wires for the paddle shifters and dccd knob, as well as the wire for the select monitor, and to start building and adding all the goodies and getting it installed (5 additional wires total). I have the DCCD knob already here, and I have some ideas on the paddle shifter assembly that I should be able to test out here soon, and I should be able to start wiring it all in starting this weekend.
My first plan is to install the DCCD knob and get that working, then the paddle shifters. I figure one thing at a time, that way I don't get to overwhelmed, so stay tuned!
Edited by eulogious, 24 March 2010 - 02:19 AM.