Need help asap with 4ac to 4age!!!!!!!

[JDMjonSR5]

OK I have a redtop big port 4age in now I have it all ready to go but I got stuck on the wiring. I found out that I can't use the sr5 dash loom with the 4age engine loom, so I just got the gets interior harness that goes from dash to trunk.

My question is do I HAVE to have the engine harness or can I use the mr2 harness that I got with the motor?

Any help is better then non. Thanks all.

[fax0815]

Use the MR2 harness, only needs a few basic things to be running, 4 earths, 1 permanent pos. supply to the ecu, 1 ignition positive, cranking signal, power via a main relay to run the injectors/ignitors, starter signal to starter.
Comming from the the loom, and important for the dash is the oil pressure switch/sender, water temp and the signal to run the rpm gauge. I´d also get the diagnosis working, cause it comes in very handy if you got running problems.
Youll also find a fuel pump output, which could be used, unless you´re putting the pump on a switch.

Dead easy, geht the pinout for the ecu, and than its just a case of tracing a couple of wires and conect them correct.

[JDMjonSR5]

So your saying use the gts dash loom with the mr2 engine loom? Got it thanks

[fax0815]

Well, I don´t know how good your wiring skills are, but thats what I whould do.

Need a bit of colour checking + mulitimeter continuity test and a bit of crossreference work.

Main advance is , you know that this ECU run your engine before, if you swapping around you might find different plugs, different wire routings....
You´ll find that trying to get a bolt in solution will take you a lot longer than just making it new, at least you know what you´ve done and what is connected to what, if there are any misstakes, you got a starting point.

[Rascal21]

What Fax said, you can make do with what you already got.
Wire it all up as you start to understand what goes where, it`s been a painstaking 3 week process for me too because I had a self-sufficient wiring loom which WOULD have worked if I had had the firewall engine harness connector on the dash loom, so you`re already way better off than me!

I cant say much more than I recently learned..

As already mentioned you need the 12v ECU power from ignition key junction (For the Injectors, coil& igniter and so forth), mine is connected to Black-Yellow (I think) @ Ignition.
In your case you save a lot of time by connecting the engine harness sensor wires, 12v switch and all that stuff to your SR5 dash harness firewall connector

ECU earth on engine head/intake (I bolted mine to intake) and remember good earth from firewall to engine head, and good earth from chassis to engine block!
What put my patience on test was ECU-ground

Just use your current alternator and wiring, this way it goes from alternator, through fender and into footwell junction box, across the dash loom and into battery +terminal!

This means your ECU harness fuse/relay box (If you have one) has to be connected to battery +terminal for powering Fuel Pump and so forth.
I`m not sure what fuel pump the SR5 uses, but if you can use that to fill a catch tank and a Walbro/Bosch from there to the engine that`d be good for the engine.

[JDMjonSR5]

Thank you guys for the help its up and running now. Can't say thanks enough.