ECU harness thru firewall - where?

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Mesozoic

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Location
Tucson, AZ
My Car
1971 Mustang fastback restomod. Caged, stiffened, lowered, on 17" wheels with 4 wheel disc brakes and Bilstein dampers. PST polygraphite suspension kit w/Mustangs Plus springs. Custom SEFI-EDIS8 EEC-V injection based on '96 Crown Vic harness (CDAN4 strategy). 90mm induction, LMAF, 80mm Accufab TB, Edelbrock Victor intake, 42# injectors, fully ported RHS Pro Action 215 heads, long tube headers. '69 351W stroked to 408 using Scat 4340 crank, H-beam rods, SRP pistons. Comp Cams 284 Magnum hydraulic roller cam, Canton windage tray and main girdle w/blueprinted standard pressure oil pump. Serpentine conversion using late model 5.0 parts. Backed by a built 4R70W, FB Performance 3000 RPM triple-disc converter, custom alum driveshaft, stock Ford 9" w/3.50:1 billet LS.
Having a tough time getting myself to cut a hole in my firewall to run the ECU harness out to the engine compartment. I've been looking at it for a while and I see an unused 1" grommet that appears to have previously been a bulkhead on the driver side. Curious to see where others have run their ECU harness... would really prefer not to cut into the old Stang.

 
I drilled mine towards the bottom of the firewall kinda by where the charcoal canister is or would be. it made short work of hiding the PCM and the EFI relays and whatnot.

 
I drilled mine towards the bottom of the firewall kinda by where the charcoal canister is or would be. it made short work of hiding the PCM and the EFI relays and whatnot.
Pics or it didn't happen. :D

 
The left inside of the firewall above the drivers feet, is relatively uninhabited. Thats where the ECC CPU is going on my conversion. All the while I'm hoping to use ideas gleaned from your work Mesozoic. I like what your doing.

BTW are you adding a PDB to your ECC harness??

Tubo

 
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The left inside of the firewall above the drivers feet, is relatively uninhabited. Thats where the ECC CPU is going on my conversion. All the while I'm hoping to use ideas gleaned from your work Mesozoic. I like what your doing.

BTW are you adding a PDB to your ECC harness??

Tubo
PDB? What's that?

I found this 1" grommet thing on the driver side firewall near the top. Mine has nothing going through it anymore, although at one time it clearly looks like it was for wiring. I might just use this for the ECU instead of cutting a hole somewhere.

 
Power Distribution Box. Relays and fuses specific to the EFI, and I've taken to adding headlight, radiator fan, horn relays and a "hot in run" relay for accessories.

I usually grab a "Power Distribution Box" from a SN-95 or newer Stang as a housing.
Ah, yes. I've got the Painless fusebox mounted close to the stock fusebox location inside the cabin, but I don't really have a PDB outside. I'm running dual fans, however and would probably benefit from having one. Most accessories on my car are powered directly off the hot side of the starter solenoid right now.

 
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