For those that have installed their Tunas, how were you guys able to run the tuna harness through the firewall, and where on the firewall did you use to run the harness? The reason I am asking is because the connector for the wideband o2, seems like it may be too big to fit into the hole on the passenger side area of the firewall.

Ken

 

I was just pondering the same thing (considering my Tuner will be here tomorrow)

 

There is a rubber plug all the way on teh passenger side corner in the firewall...do a search...Ive seen alot of pictures on this site of it. Just push the rubber gorment from the inside (behind the glove compartment all the way in the upper right corner)

 

Yeah.. I figured that much out, but Illrunya has a point, the connector looks significantly larger than the hole.. Or is it a optical Illusion?

I have to also run wiring for my MAP Sensor, and some other wiring through that damn opening..

 

What did you use to reach the grommet from the inside?? I was thinking a long screwdriver or some metal stock to push it out..

 

REREAD MY POST....I already mentioned that I dont think it can fit in that hole. Ive seen and used that hole already.

Ken

 

read my post on how to do it. Its in the UTEC tuning section. Takes 15 minutes. I did a write up on it.... RRR

 

Actually, just push it in from the engine bay. It'll just fall down on the floor.

 

You can take the outer part of the connector apart to give yourself some more room and then reassembly it once you are though the firewall.

 

That sent shivers up my back when I read it.

There is a large grommet in the front inner fender area (both sides), that the factory uses to run the harness to the engine compartment. Thus the cables will run through the grommet, into the inner fender area and exit at the front of the wheel arch. If you look under the hood you will see on both sides a large number of bundled wires in these areas. Just route along the existing bundles.

The grommet itself is very large. You can put your fist through the hole to the under dash area. Cut an X in an unused area of the grommet and route your wiring through the new hole. My suggestion is that you seal the grommet to the wiring with butyl rubber, available at Home Depot in the electrical section (near the wire ties). The butyl rubber is $3 for a brick size chunk - you will have enough for the rest of your life.

 

Different grommet.. there's another grommet up in the corner by the fender and the firewall.. We were just pondering the easiest way to get it out since it runs directly into the passenger compartment. I know which your talking about because I pondered using that one but decided against it.

 

I have no idea how the heck you can get the wiring through that hole.. I removed the "Shell" from the DB15 connector, and the "Depth" of the connector+ wires coming out of it, even tucked off to the side, won't fit through the hole, at least, it wants to try to shear off the wires..

I suppose I could wrap electrical tape around it to keep everything protected and in check, but it certainly doesn't seem to want to fit.

While I was under the dash, I spotted the plastic guard for the steering linkage, its gigantic and probably could have a small hole made through it without effecting much, but I'm reluctant to try it because of its shape on the firewall..

I just want to get everyone's thoughts before I try to go any further. I feel like an utter moron since I do this stuff all the time, but I'm stumped as to why you were able to get the wiring through, and I can't easily.

 

Why? You would be done by now if you went with the inner fender grommet....

Refer to,

Grommet Access

The left and right inner fender grommets are where the factory runs the bulk of its stuff (wires, hoses and hood latch actuator.)

 

Yah good point, I was reluctant to fiddle with the splash shield.. are you referring to the second 2" grommet at the top of the fenderwell also? Because that second one is also the same size as the one that goes through the firewall. I didn't look close enough to see if there's another giant gromet, I suppose I'd have to remove the wheel and drop the entire splash panel to see for sure.

 

The grommet in question is about 2" x 3", with a large area that is currently unused. If you look up to the right of the glove box (remove the box) the grommet is right there. When you drop the fender liner it will be very obvious.

(This is also a good time to make sure the firewall seams are sealed. I could look right into the passenger foot well on my Evo!)

There are three areas in the grommet. With respect to the right side, two out of the three areas in the grommet are used. The center has cables and the other has the windshield washer fluid hose. The remaining area is where I have the factory gauges wires / boost hose routed.

To make life easy pull the grommet out into the inner fender area. There is no problem getting it back into place. This makes working with it easy (e.g. cutting a X, pulling the harness, etc). In your case cutting a horizontal slit might work out best. Route the wires along the factory harness and wire tie in place. No big deal.

As cited above reseal the cable to grommet area with the rubber material from a building supply store. GE silicone sealer doesn't stick - trust me.

You can just turn the wheel all the way out and drop the rear portion of the fender liner. Pulling the wheel will make accessing the area simpler, but it really isn't required. I didn't bother to remove he wheel on either side. (I have power to my head unit run through the left side grommet.)

There is no reason to drop the (under) splash shield.