I needed to route some wires from the engine bay to the passenger side of the cabin. The driver side already has a pre-drilled hole in the firewall with a rubber plug but the passenger side does not. (Both sides have triangular holes connecting the wheelwell to the engine bay.) There is no extra room to route wires through the harness plug so some drilling is required. It took me while to figure out a safe place to drill a 1" hole (and I could not find any pictures on this site) but the location pictured below works well:



The ECU is just behind this hole so it allows for clean direct wiring inside the cabin.

 

Where on the passanger side does it need to go? I recently drilled a hole in the drivers side of the firewall, right next to the tranny tunnel. It was a good spot to run the wires I needed to run.

 

Sorry - don't understand: the red arrow shows where the hole goes.

There is no need to drill any holes in the driver side:

 

Depending on the level of mods that you have, you could also feed them through the ECU harness through the FW. No drilling necessary.

 

I'm thinking he meant what is the wiring for that it needed to go where you routed it.

 

True - but I'm planning on running a lot more wires.

 

Wideband signal for the moment but dual EGTs and oil temperature will follow.

All are to be routed to a set of PLX sensor modules behind the ECU.

 

I have quite a bit of stuff run through there, but I just ran them through the grommet - just sliced a slit in the grommet and ran things through. I have wideband wiring, a 3.5mm silicone vacuum hose, and I'm sure a ton of other junk running through there.

Drilling a hole is much cleaner overall, but I try to not drill/cut on my FD as much as possible . But, that's just me.

Dale

 

Moconner, I think that is a good solution. I looked at that spot before but got cold feet when it came to drilling holes . In retrospect, I think I should have drilled the hole. I will have to revisit my wiring in the future and will probably do what you did. That space behind the ECU is packed with a lot of crap. Tough to get much more in there.

 

Not a huge fan of drilling into my car either but since there was an OEM hole in the exact same location on the other side of the car I justified it to myself. It pretty much looks OEM too.