Running 1JZ harness

[NgoFcukinWay]

so i've heard that running the harness through the firewall and out from behind the dash would be best as I don't have to worry about extending the harness. We're gonna start prepping my car this weekend to be ready for the 1JZ swap, but I just wanted to know if anyone had a picture or a good detailed explanation of where to drill a hole into the firewall to run the harness. Thanks in advance.

 

[BlackMKIII]

And you planned on putting the ECU where? I'm not being sarcastic.

 

[suprahero]

I drilled mine where the speedometer cable goes through. I think that's where it went through. I know when the motor is out, you can see where to drill it. I may have a picture in my buildup thread. I'll have to look and see. Aaron showed me a picture of where to do it.
It's still not going to reach the ecu without extending the wires.

 

[AF1JZ]

I actually didn't extend the part of the harness that goes to the ECU. I only did the ones for the accessories and ignition (2 plugs). It's tight, but I have the ECU is the stock location. Now, I have a soarer engine and harness. So, I don't know if the length of the wires are different from the JZA70 harness. One day I might extend them to make the appearance better.

 

[NgoFcukinWay]

Interesting. I didn't know that running the harness that way would still have it coming up short. How much longer would it need to be to reach the ECU's original location? Reason I'd like to avoid cutting up my harness is that I don't want to add bad connections and whatnots to a possible cause of an electrical problem. Would a replica fields harness solve that problem and also double as something to splice into for electronic piggy backs?

suprahero - if you can find that pic, that'd be awesome. Last I remember, your build thread was like 9872394587 pages long, so if you don't mind finding it in your build thread or at least where ever you have the image stored, I'd greatly appreciate.

 

[bluemkiii]

Here are some links to threads, as I plan on going this route also, If I remember correctly you just rotate the ecu so the plug inputs on the ecu face the driveres side. http://www.supramania.com/forums/showthread.php?t=48732

http://www.supramania.com/forums/showthread.php?t=47323

 

[JonoTurbo]

Here's where I drilled the hole for my harness:

Look at the firewall below the speedo cable hole, there is a hardline running along near the top of the transmission tunnel. There is a clip for the hardline bolted into the firewall just above an open space. I drilled my hole on center just below the bolt at this point. I recommend going with a 2.5" hole saw. Drill right there and at most you'll hit the corner of a plastic bracket.

Using this method I was able to mount the ECU in the "stock location" although it faces the other direction and you'll have to get creative with the mounts it works. You still have to extend 18-30 body harness wires, depending on options.