Relocating ECU

[ECLIPSE95]

So I decided to relocate my PCM/ECU and I was wondering I can extend the wiring harness about 3' or 4'so that the ECU sits inside the cabin and the rest of the sensor plugs are in the engine bay. Is this going to cause any problems??

 

[mentalTSiAWD]

You're gonna need a good electrician. Aren't many of those wires on the ECU calibrated for a certain resistance?

 

[VelocitàPaola]

You're gonna need a good electrician. Aren't many of those wires on the ECU calibrated for a certain resistance?

No, but it will be a pain in the ass to cut and solder in nearly 80 wires.

 

[ECLIPSE95]

No, but it will be a pain in the ass to cut and solder in nearly 80 wires.

So do you think I will be good with leaving the junction inside the car along with 2 other plugs with their sensors?(MFI and Fuel pump relay) I really want to do this, and if I take my time I hope for good resluts. I will need to also extend the wiring for the plug that connects the other part of the wiring harness.

 

[totaleclipse_05]

Can't the stock ECU get too hot inside the car? Thought I read that from 2GNT when someone asked about relocating their stock ECU in the car as well.

 

[ECLIPSE95]

Can't the stock ECU get too hot inside the car? Thought I read that from 2GNT when someone asked about relocating their stock ECU in the car as well.

Yea I saw that, some have already relocated it successfully under the passanger side seat. In that same thread they also said it was a lot hotter under the hood next to the engine.

 

[jrohner]

Can't the stock ECU get too hot inside the car? Thought I read that from 2GNT when someone asked about relocating their stock ECU in the car as well.

Have you never opened your hood after driving? I hope my car never gets as hot inside as it is under the hood.

 

[ECLIPSE95]

52 wires to be exact, so when I re-solder that would be 104 connections plus 52 shrink tubings and wirewrap...

 

[murray1]

Have fun with that

 

[ECLIPSE95]

Have fun with that

I don't think it would be too bad if I take my time, but will it be worth the effort....I sure hope so

 

[VelocitàPaola]

Each wire has a unique color combination, so all of those labels were probably superfluous! Oh well, live and learn, and if they help you stay organized then they weren't a waste of time.

 

[vinnio]

Woah!! I would have done it one at a time, but to each his own. Have fun!

Just wondering, whats the reason for the move?

 

[ECLIPSE95]

I'm working on building my car from the ground up(turbo build). I wanted to make more room in the engine bay and I was going to put the intake where the ECU and fusebox used to be.

as for the wiring harness I knew each wire had its own color combination to it, but I wanted to make sure I get the right ones when I extend the harness. Also I noticed some wires, like the 4 or 5 yellow ones are really close and they could be mixed up on accident.

 

[squirley8888]

Each wire has a unique color combination, so all of those labels were probably superfluous! Oh well, live and learn, and if they help you stay organized then they weren't a waste of time.

It also makes for a quicker reference imo. I am also thinking about putting the ecu inside the car along with the fuse box. I plan on doing a wire tuck and the ecu and fuse box just dont look like they belong.

 

[ECLIPSE95]

Yea the fusebox I wouldn't move to the inside of the car, I'm not sure if I can just re solder the wires so I can tuck the fuse box behind the driver side fender or something.

 

[ECLIPSE95]

Ok can anybody tell me what gauge wire the ecu/main harness uses?? I thought it was 16-18 gauge, but I think the smaller wires are 20. I already soldered 20 or so wires with 18 gauge wire on what I think is 20 gauge wire. I just noticed this. Will this mess up the resistances on some of the sensors if I use bigger wire??? help??

 

[VelocitàPaola]

Sensors draw very little current, so you could easily get away with wire as small as 22 AWG.

 

[ECLIPSE95]

so I should be fine with 18 gauge going to 20 gauge? I think that some of the bigger wires are 16 gauge but im not too sure...

 

[cano86]

In my opinion it shouldnt be a problem I just finished rewiring my whole car last week since my wiring harness got burned totally and completely and I used 18-16-14 and 10 g. wire and everything is working perfect nothing got harmed. Damn I was at the junkyard on saturday and I saw an N/T at the yard with a relocated computer it was placed at the same location as the turbo ones but that one was laying down if you would've been closer to the yard I would've pm you so you could pick it up is really cheap in that place the whole wiring is from 40-50 if you take it out yourself I took some door popper motors out of it to shave my doorhandles and I only paid 10 dollars for the pair thats good.Am going to get my windshield on thursday for $30 from the same car.

 

[matthewdesigns]

If I were you I'd grab a second, identical harness and splice the same colors in where you are extending your original. That way there's no confusion about what wire is what when something breaks in the future.

 

[420agstuner]

let us know how it turns out when your done. I plan doing the same thing but I'm going to move my fuse box to.

 

[crimsonGST]

The resistance will be so miniscule you, nor the ECU, will ever know the difference. The best way to try would to use a meter, but you would have to use a power source to check the resistance, voltage, and current. Simple OHM meter would do.

 

[Car_guy_09]

I have thought about doing this...

 

[VelocitàPaola]

The resistance will be so miniscule you, nor the ECU, will ever know the difference. The best way to try would to use a meter, but you would have to use a power source to check the resistance, voltage, and current. Simple OHM meter would do.

Huh? The voltage in most automotive systems is constant at 13V - 14.5V. The resistance can be directly measured with an ohmmeter, which is found in almost every modern digital multimeter (DMM). The current, then, can be extrapolated using Ohm's law.

Anyway, the resistance will be negligible in most cases. Like I said, sensors pull very little current; undoubtedly less than 50mA each. Ground and power wires should obviously be a little heftier. Alternator control wires should be even larger. A good indication is the pins on the ECU connector: longer pins generally mean the corresponding wires should be able to handle more current.