Educate me on engine looms


Well-Known Member
Hi guys,

I have been contemplating doing an engine swap in my car as a DIY.

I've never done one before but the car is just a track car so time isn't an issue.

The car has a 6A12 MIVEC in it and has the fusebox from an FTO (both under the dash and in the engine bay).
It also has the climate control system installed.

I would want either a CM5A or a Evo V/VI swap, both of which have their pros and cons for me, one of which is procurement.

Either way though before I make any purchases I would like to know what would be involved in the wiring department.

I understand there is an engine loom that goes through the firewall and into the ECU.

1. What other looms are there in the engine bay and interior that would need changing?
2. Since the fuseboxes are from an FTO and all the fuses for power windows, lights, AC, heater etc etc are in these fuseboxes, does that mean these need to be replaced or could I just "plug in" the engine loom and leave the rest as is?
3. If the FTO wiring needs to be taken out, how easy/hard is it to integrate the CM5A or Evo harnesses (excluding engine harness) to standard Lancer harnesses?
4. Are there any other considerations needed when dealing with the harnesses?

Please keep answers for the electrical side of things only here, I am doing separate research for the mechanical issues.


Active Member
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If you want to over complicate the swap sure you can throw in different fuse boxes, and mix match body harnesses. The fuse box the car originally comes with is all you need. Another point to consider is if you want power windows and dont have it and have 96 97 early 98 Lancer non MR then the harness does not have these wiring circuits.
If its been butchered then you are best to start again.
The fusebox belongs to the front body harness. If you are smart you keep it stock if the rest of the cars electrics is stock.
The swap was probably done and use the FTO fuse box was because it was the most obvious choice at the time seeing as it belongs to the engine. But engine bay fusebox only needs to kept the chassis happy.
Basically only the engine harness needs to be mated to the car. Aircon clutch/fan system jumps via a seperate plug and alternator wiring/starter harness is also seperate single plug.
Its no different than swap any other engine into the chassis. You just want it neat and working like OEM. When you start mix and matching the engine bay fusebox and interior fusebox harness will you open your can of worms.
IF you want to mix EVO engine harness with Lancer 1.8 interior body harness, and Lancer 1.8 body harness the cooling system wiring and HVAC wiring has to be addressed.
I can push you to the right direction. You investigate and figure it out yourself.
If you need help to do so I can provide my help/services.
I cant give every detail on a silver spoon though.

CM5A/EVO4-5 use a common fan control system. EVO6 is different. You cannot just say you want EVO5-6 and expect the HVAC system to plug in a work like OEM. The wiring pin out differs slightly.
I mention this as well because base model Lancer electric is different. Engine cooling and AC fan are single speed control.

Not sure why you want to go CM5A but its near impossible to source, makes little power with its baby turbo. 110-130kw at wheels.
GO back to a 4G93 and have a reliable turbo kit done. 200kw atw piece of cake.
Want 250kw atw reliable 4G63. Any more is a ticking time bomb.

Depending on what you are supplied with there are various way you can go about this. You can bend the rules if you arent using factory ECU factory low impedance injectors, along with its injector resistor pack.
Mechanically wise there are also different ways to skin a cat. Like if you are that inclined you can use the stock Kframe even tho it lacks the correct exhaust hanger, but you still need EVO north south member.

Decide what path you want, how far you want to go, then maybe I can give some more specific advice.


Well-Known Member
Thanks @Hens
I have found an Evo V but it is advertised as engine and engine harness (including ECU) which is why I am considering the other harnesses in the car.

Though I originally was thinking of a CM5A swap just for the gearbox simplicity and slightly lower engine weight (as I use the car on the track so handling is important) however I am not sure it is worth the trouble and would really go 4G63 and just run stock power/ECU which should hopefully mean it drives like a stock car and is as reliable as a stock car.