Hello! I’ve been reading the motoIQ resto mod and was wondering how they did the rewire of the electrical harness? I would love to do the same thing with my car but don’t know where to start.

The reason I am asking because I’ve been seeing pretty low voltages with the stock alternator. I am at 12.5V at idle.

New plug for the alternator

Current mods (1999 FD3S)
-battery relocated to trunk (JDM model)
-Fuel pump relay upgrade and wired to battery
-Positive wire from battery straight to fuse box
-Advance Alternator 130 amp (not installed and is why I’m asking about rewire)
-RaceOnly pulley kit with air pump delete
-EFR 7670
-Greddy V-Mount
-Haltech Elite 2500
-Haltech wideband controller
-Radium rails with ID 1050 and 1700
-Walbro 450 LPH Fuel Pump
-4 Defi A1 gauges with controller
-Optima battery red
-OMP delete

I know I listed things that are unnecessary but would like to give as much information as I can about the car.

All my lighting is stock and I do not have an upgraded stereo system. Still have power steering and A/C.

 

If you have a low charging voltage, you should troubleshoot that as an independent issue instead of trying to rewire the car. There are certain "mods" that should only be done when everything is working as it should in base configuration. If you put "mods" on top of issues, you can compound a problem and make it extremely difficult or impossible to find.

Fix your charging issue first. Start with going into great detail about HOW you did the battery relocation and the condition of your engine grounds

 

What size power and ground wires did you use? Are you running a dedicated ground wire from the battery to the engine block?

I'm not sure I can help on the alternator side of things. We are using a DC Power alternator that was plug and play.

 

Just want to make sure, your measuring the voltage at the alternator or battery right? Reason why I ask is if you are taking the voltage from what the ecu is reading, that could be a different issue all together. What the ecu shows and what the alternator is actually producing may be different.

 

I have a 00 AWG positive cable running from the trunk, underneath the carpet, through grommet in fender then to the fuse box. My 00 AWG ground is mounted to my rear strut bolts.

My OEM grounding straps isn’t in the best of shape but I’m planning to redo all the grounds the same time as the electric harness rewire.

00AWG Grounded to the rear strut bolts and I am not running a dedicated ground to the block from the battery.

The reason I got that specific alternator was because it was discounted from shipping damage. The damages were only to the pigtail which is easily replaceable.

Ive been measuring from the ECU this whole time. I didn’t know those read differently. Which one should I read for the most accuracy?

 

Definitely take a reading at the battery and/or alternator. Is the alternator powder coated by chance? Just make sure the alternator is properly grounded as well.

You should run a ground from the battery ground location you made at the strut tower to the center iron on the block as well. I would bet this is a grounding issue.

 

My current alternator is OEM and is not powder coated.

Will do brother. I’m planning on buying a terminal bus bar for the ground so I can add extra grounding to the engine bay.

 

Does your pulley kit under drive the alternator? I’m not familiar with those pulleys.

 

Pull that casing apart, chase the threads on the bolt holes, make sure no paint or whatever that is is on the inside of the casing. Clean where the casing bolts make contact on the outside as well. Make sure there is metal to metal contact on the mount. You could even run a ground strap from the casing bolt if the mounting surface isn't clean or anodized.