3SGTE Harness Routing and Lengthening Options

[WannabeGT4]

When you all had your harnesses done, did you re-route the harness to exit on the timing belt side instead of the distributor side or did you just lengthen it and run it behind the intake manifold then through the hole in the firewall on the passenger side?

[jgreening]

When you all had your harnesses done, did you re-route the harness to exit on the timing belt side instead of the distributor side or did you just lengthen it and run it behind the intake manifold then through the hole in the firewall on the passenger side?
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Mine is lengthened and still fits in the stock black plastic box behind the intake manifold. Many people end up removing that when they lengthen it.

[WannabeGT4]

Sorry, I think I phrased my question wrong. You're talking about the black box that is between the head and intake manifold right?
What I was wondering was, did the wiring that enters the cabin get extended then routed between the intake manifold and firewall or was it extended and re-routed so that it didn't even exit on the distributor side of the engine.
Do you have a pic of how yours is set up?
I'll be doing my harness my self and just wasn't sure how most people did it. Thanks.

This post has been edited by WannabeGT4: Oct 20, 2005 - 8:50 PM

[jgreening]

You know what, I think I remember that mine is different because it came out of a MR2. IIRC, the wiring harness is on the opposite side so I am probably not much help to you.

[Defgeph]

do one wire at a time
use heat shrink tubing at all soldering points
only lengthen 30 to 40 inches

wrap in electrical tape and wire loom.

Plug in your ECU.
Should take about 2 to 3 hours.

DEF

[lagos]

i cut a hole right behind my ecu so that i wouldnt have to extend the harness. worked out well

[WannabeGT4]

do one wire at a time
use heat shrink tubing at all soldering points
only lengthen 30 to 40 inches

wrap in electrical tape and wire loom.

Plug in your ECU.
Should take about 2 to 3 hours.

DEF
[right][snapback]347147[/snapback][/right]

Thanks def, but which way did you run the harness? From the Distributor side or the timing belt side?

[Defgeph]

dizzy side.

To many wires to have it routed from the timing belt side. IMO

My harness wraps right around the IM to the stock firewall location, down to the ECU.

DEF

[WannabeGT4]

The 5S harness comes from the timing belt side doesn't it? I figure that I can make up that 30 inches easily by not running it between the intake manifold and head then around between the intake manifold and firewall. I'll just extend the few wires that have to be on the distributor side.

This post has been edited by WannabeGT4: Oct 20, 2005 - 9:23 PM

[Defgeph]

Makes sense. But It might clutter up your engine bay. Having a few wires go here, a few there, some around over here, some down there.

Or one nice, neat, chunky wireloom going into ur firewall down to your ecu.

Its up to you. I know how you feel about extending the harness, its a pita. You just gotta jump in and do it. before you know it, you'll be done.

Do what you think is best.
good luck man
DEF

[lagos]

The 5S harness comes from the timing belt side doesn't it? I figure that I can make up that 30 inches easily by not running it between the intake manifold and head then around between the intake manifold and firewall. I'll just extend the few wires that have to be on the distributor side.
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are u talking about trying to run the harnes in on the drivers side of the car?

[Rjb23]

Lengthening it 30 or so inches is gonna take way longer than 2 or 3 hours. It took me 8 hours to do one side of the wires, and another 8 to do the other. Its not an easy job.

[Defgeph]

I did it in 2 1/2 hours by myself.
I know its not easy.

[lagos]

jeff, when you did yours... did you just use the spare wiring from your 7a harness for the extension?

[Defgeph]

jeff, when you did yours... did you just use the spare wiring from your 7a harness for the extension?
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I used wire from radio shack

[WannabeGT4]

Makes sense. But It might clutter up your engine bay. Having a few wires go here, a few there, some around over here, some down there.
[right][snapback]347169[/snapback][/right]

are u talking about trying to run the harnes in on the drivers side of the car?
[right][snapback]347184[/snapback][/right]

Sorry. I guess it's a little difficult to explain what I'm thinking. I'll try again.

Instead of lengthening every wire that enters the cabin because the harness is wrapped around the intake manifold, I'm going to change the route the wires travel in effect turning it into a LHD 3SGTE Harness. Only the wires that have sensors on the distributor side of the engine will be routed between the intake manifold and head. The harness will still enter in the factory 6th gen location.
I'll just take a bunch of pictures and do a little how-to when ever I do this maybe that'll make more sense than trying to explain it all.

This post has been edited by WannabeGT4: Oct 21, 2005 - 8:44 AM

[Defgeph]

there is not that much room to have all those wires traveling between the IM and the head.

[WannabeGT4]

???

It looks like there is plenty of room to me.

[Defgeph]

Again its up to you. There is alot of heat in that area, it would worry me to run every wire through that location.

[WannabeGT4]

Thanks every one for the input. You've all been very helpful.

[lagos]

WannabeGT4

ahh i know what you mean... i dont think youll be able to do it tho. its kind of hard to explain, but a lot of those wires Y off into different placed on the drivers side. so you still have to run them there, and then come back behind the intake manifold and make them all longer... youll see when you start doing it.

[WannabeGT4]

I think I can get it to work. I'll just lengthen the wires that have to go on that side. I should have added that when I said "Only the wires that have sensors on the distributor side of the engine will be routed between the intake manifold and head." If I get the harness apart and realise that this just isn't going to happen no big deal. I'll just put it back together and lengthen it the way def did it.

This post has been edited by WannabeGT4: Oct 21, 2005 - 1:43 PM

[Dr_Tweak]

I did a 3SGTE/ST harness for someone yesterday and was doing some thinking. The 3SGTE harness is actually just as long as the stock USDM Celica harness, but the wiring is routed the wrong way coming from the injector side of the engine. It wouldn't be that difficult to cut open all that looming, route the wiring out the back of it, and have a very clean harness that didn't need to be extended at all.

That probably doesn't make any sense unless you've compared these harnesses side by side, then you probably know exactly what I'm talking about

[WannabeGT4]

I did a 3SGTE/ST harness for someone yesterday and was doing some thinking. The 3SGTE harness is actually just as long as the stock USDM Celica harness, but the wiring is routed the wrong way coming from the injector side of the engine. It wouldn't be that difficult to cut open all that looming, route the wiring out the back of it, and have a very clean harness that didn't need to be extended at all.

That probably doesn't make any sense unless you've compared these harnesses side by side, then you probably know exactly what I'm talking about
[right][snapback]347631[/snapback][/right]

I haven't had them side by side but it makes perfect sense to me.

[scothaniel]

It wouldn't be that difficult to cut open all that looming, route the wiring out the back of it, and have a very clean harness that didn't need to be extended at all.

I did something like that with my harness. You still have to cut and extend a bunch of wires - since the length of the wires are relative to the harness routing.

For example, the 4th injector plug on the JDM harness has the least amount of wire, since the harness enters from the right (when facing the motor)
On the US harnesses, the 1st injector plug has the least wire , since the harness enters from the left.

I have been enable to route the 3rd gen 3SGE wiring into a 6th gen without having to extend the ECU/Dash plugs. You still have to extend the ignitor, coil, CCO and VISC wires, but thats nothing in comparison. Now if only these harnesses were easy to get!

Oh, and I highly recommend running the wires behind the intake manifold instead of through it. Nothing like having to pull the IC, TB, and valve cover to get the wiring harness out - or to get to the injectrors.

Scott
90 All-Trac+
96 Celica +
Michigan

This post has been edited by scothaniel: Nov 1, 2005 - 11:09 AM

[Dr_Tweak]

Yes, that's exactly right, since it's sequential injection it wouldn't run right unless you moved the injector plugs around so one would have to be careful to get that right. But yeah I think this is a much better option to extending the whole harness.

-Doc

[scothaniel]

Well, that was just one example. Nearly all the wires will be the same way as the injectors, except the components on the left side of the harness ( Map sensor, alternator, A/C ). Everything on the center / right side will need to be extended.

Scott
90 All-Trac +
96 Celica +
Michigan