5.0 EFI Harness Firewall Hole

One thing you need to do to install EFI on your Meteor is to run the EFI harness thru the firewall.  This allows you to keep your computer safe and out of the weather underneath your dashboard.  It's always a challenge to find a good place for a computer when doing an EFI swap.  Some cars are harder than others, but the Meteor is pretty easy....almost too easy:  Check it out!

First off, this is where I've chosen to run mine - you don't have to do it this way, but I believe it's the best and cleanest location to run the computer harness thru the firewall. It's best to do this with the engine out because it gives you more room to work.

I was looking for a spot to cut the hole in the Meteor firewall when I found this factory "knockout" plate....it's nearly the same shape as the Ford Firewall Grommet you need to install....Perfect!  The knock-out plate is just to the right of the heater motor cover-plate if you are standing in the engine bay facing the windshield.  It's a canted oval shaped piece.  Start by removing your glove-box, heater box and firewall insulation.  I didn't remove all of mine until later, but I recommend doing it before you start.  The reason is that the sparks from the hole-saw may ignite under-dash wiring and insulation.  Remove it all first as a precautionary measure!  

Start by making one hole on the upper part of the knock out using a 1-1/4" hole-saw bit.  Then measure 1-5/8" from the center of that hole and make another hole.  You'll notice you are almost but not quite totally cutting out the knock-out.  Once you have the two holes cut, you can trim the excess material out using either tin-snips or a hacksaw or cut-off wheel.  Just be careful.  See how well the firewall grommet fits.

Take a look from inside with the heater box in......perfect area for the computer and harness to snake and hang out under the dash.  Final computer resting area is up to you but at least it's out of the weather.  This is also an excellent time to replace the firewall insulation, rebuild your heater box and replace the core, and also your crumbly glove-box liner.  Keep checking back for more info!