Hey guys.

I’ve been building this car for a little over a year now and the last hurdle to get this thing running again is the wiring issue. I am torn between two options.

Keep the hacked up front harness and connect my Haltech S2 into it, or try and delete the front harness and go full custom PDM system.

I have been converting the car to a big single turbo setup and have changed all the fluid sensors to Bosch temp and pressure sensors. The coils are smart coils. New injectors, AN fuel system for E85, the whole thing. Basically everything about the cars engine is redone. The interior is bone stock except I will be putting a digital dash in. I’ve been trying to wrap my head around the wiring with all the relays and dead connectors and I can’t seem to make any progress in one direction.

I need some advice on how to proceed. I think the easiest course of action is to just try and get rid of the front harness entirely use a Haltech PDM and then tap into the dash connectors for the pin outs I need. I think either way it’s a ton of work. Let me know what you guys would recommend I do. Any input would be really appreciated. This is my first time tearing into a car this hard and I’m a little in over my head lol.

 

Since your car is rhd, the lhd wiring diagram isn't 1:1 with what you have. You will need to read the Japanese manual to get you out of the situation you are in. Alternatively you can probe 1 wire at a time and see where it goes until you decipher the whole harness. To help narrow it down, I can say all your charge harness wiring is the same between lhd and rhd.

Keeping things simple is the best way to mod these cars. Doing things to this extent for the sake of doing it very rarely ends well.

 

My thoughts are that the wiring in the front harness is already botched. It would be simpler to cut it out than try to build a flying lead to route into it? What do you think? I’m already this far in man. It’s gonna be work either way lol.

 

The shortest path to an end would be to identify what in the front harness is relevant to your configuration, find the associated pins and dump everything else. Once you have the relevant circuits identified then you can integrate it into what you're doing.

For as far as you're taking it, I don't think there is anything in the front harness you need. The 2 fuse boxes you can consolidate amd everything else is ac, abs, radio, headlights and so on. Just accessories. All of which you can either delete or build a separate circuit for and integrate it into your harness.

Take your situation in pieces and you'll be fine. You're looking at the whole elephant and its overwhelming you. Focus on one thing at a time and everything irrelevant will just melt away.

 

So you wouldn’t recommend a PDM and deleting all the front relays and fuses?

 

No but you're too far gone to go backwards you say. So you have to see it through or..... go backwards

 

Make a list of what you are going to run first. Pdm gets my vote. It is a ton of work but the result will be a very simplified system and troubleshooting it will be a breeze. These cars are 30 years old now, old wires and old circuits will eventually reveal more gremlins.
do your homework and do it right . I kept some oem features like the ABS and A/C and isolated them from the pdm and i have been happy with the results