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Thread: Wiring Experts! Seperating looms for engine swaps?

  1. #1
    ......... Carport Converter jeffro ra28's Avatar
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    Default Wiring Experts! Seperating looms for engine swaps?

    Probly not the most technical of questions but it would sure save some tedious work and time if someone could help me! This is my biggest nightmare!

    Please also note i am a complete uber noob when it comes to wiring, hence half the reason for this conversion so i can learn about it!

    I am seperating the loom on my uzs131crown front cut. I only intend to use the engine, auto box and ECU which will eventually end up in my ra28. Ill be ditching the abs system, traction control and all that jizz.

    Now to the point. I have removed the engine wiring harness and the "engine control unit" (ECU). Which all the wiring for was on the left hand side of the car and went through the firewall on that side also. Basically all i have to do now is seperate the wiring from the firewall and fuse panels. The chassis and engine are now seperate from it entirely.


    My question is. Is there any wiring on the right hand side of the car that i need to keep?
    Most of which i beleive is traction control, abs brakes and the air bag system. If it is entirely these added accesories then i guess i can ditch it. I do recall tho white wires from the alternator going through the right side of the firewall also??? Another worry is that i found the fuse legend sticker on the footwell on the right hand side and it tells me that this is were the ECU and engine fuses are!? Which worries me. Would this be a big deal to make my own fuse panel for the engine and ecu when its in the celica? Or should i try my best to sort it out and retain the current fuse panel on the right hand side?

    I am going to be running with the factory auto box and ECU for starters(hopefully upgrade to adaptronic ecu and a shiftkit for the box in the future). I have found ECT???? and the "engine Control" boxes. Are these the only boxes i need to keep? Where is the auto transmission computer?

    When it comes to installing the engine into the ra28 what is the best way to go about rigging up the ra28 key barrol and powering up the the 1uz ecu and engine in this situation? Should i put aside some of the uzs crown wiring from the key barrol onwards?

    Please spend the time to answer my woes.

  2. #2
    Toymods Pimp Chief Engine Builder Norbie's Avatar
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    Default Re: Wiring Experts! Seperating looms for engine swaps?

    Not sure if this applies to your situation, but with my JZS147 Aristo front cut (2JZ-GTE) I kept the wiring between the ECU and engine, and ditched everything else.

    Then I connected wires to a few of the pins on the ECU which normally connect to the body harness: +12v, earth, fuel pump, starter, tacho, that sort of thing. The Aristo had something like 11 electronic modules (including ABS, trac, lots of other stuff) but the ECU doesn't seem to care if they're all missing.

    HTH

  3. #3
    Junior Member Backyard Mechanic jonra23's Avatar
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    Default Re: Wiring Experts! Seperating looms for engine swaps?

    Hi
    The way that i generaly do it is;
    1. Get a roll of masking tape and texta and label what every plug does.
    2. Pull whole loom out of car including relay blocks, fuse pannels etc.
    3. Re-assemble loom on floor, put cable ties on Y/T intersection in loom, remove all of the tape wrap.
    4. With a wiring diagram from donor car remove all wires that i do not intend on using, lights, climate control, gauges etc. Do not remove a wire unless you can identify what it does and are sure do not need it.
    5. When all excess wires are removed mounty ECU, control boxes, relays etc into project car and dummy fit loom, start at sensors etc and route wires back to ECU, lengthening or shortening wires as required using solder and shrink wrap.
    6. Using original wiring loom run old ignition wires to control ecu relay, (make sure that there is no "resistor wire" as some cars did not run 12 volts to coil when running by resistor wire rather than an actual resitor at coil), gauges etc.
    7. Test run and then do final install and wrap with good quality insulation tape as going.



    With the fuse box i generaly get a small hella or similar fuse box and place it near battery and run power source for ECU relay, fuel pump relay etc from there.

    regards
    jon

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    Founding ****** Automotive Encyclopaedia Mos's Avatar
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    Default Re: Wiring Experts! Seperating looms for engine swaps?

    Quote Originally Posted by jeffro ra28
    Probly not the most technical of questions but it would sure save some tedious work and time if someone could help me!
    I'm sorry to say this, but it *will* be tedious and *will* take time, and you would be extremely lucky to have someone do all the homework for you and tell you how to do it wire by wire.

    What you're asking is a very high level approach, but the answers you are looking for are down to the lowest level (without getting inside the electronics). Kinda like the difference between the words "program the CNC lathe", and each step of programming.

    From a high level perspective, you take the donor (UZS131) engine loom and keep most of it (usually all of it unless you want to clean up the loom to remove uneccessary wires - but then you have to understand what each wire does exactly).

    You also take the donor chassis loom (cowl, dash, and engine bay), work out what *circuits* you need and ditch what you don't need. At this stage, depending on the desired level of completeness the number of "required" circuits is different.

    You then take your host (RA28) loom and work out which donor *circuits* you can accomodate using the host gear, and then fabricate or adapt the donor's loom for the remainder of the *circuits* you need for the donor engine.

    A circuit is composed of a number of wires, relays, etc. some of which interact with other circuits. Circuits are things like fuel pump wiring, power supply (to ecu and others), alternator, (in your case a separate) ECT, A/C, abs, trc, cruise control, central locking, etc. (there's lots)

    In general for time efficiency you use as much of the host circuitry you can and only fabricate the additional circuits you need.
    In terms of an ideal solution, you would probably ditch as much as you can of the donor and fabricate everything (30 year old cabling shows its age), but in reality this almost never gets done because it is simply too time consuming.

    As an example, in a (barstool of a) TA22 (Hi Rod ;p) being wired up right now, virtually the entire engine bay loom has been ditched and built from scratch with virtually every wire and pin new, and running completely differently to the factory setup.
    A small portion of the engine bay loom that extends into the cabin has been retained, as has the cluster loom - both of these have been extensively adapted to suit the layout of the new wiring, including the engine management and accessories. Relays added on the 22 were: 4 x headlight, fan, parkers, efi, starter, fuel pump. In an ideal world you could add more.

    With older cars there is very little support in the factory wiring for anything resembling the more modern efi setups, so you're pretty much forced to fabricate most circuits from scratch, or reuse the donor ones.

    I have seen cars where the donor chassis loom was installed in the host with only the major power feeds connected (like battery, ignition, starter, fuel pump) between the donor and host loom. The setup runs, but it's far from pretty and definitely not something you would call complete.

    It depends what you want to do and how complete you want to make it. In contrast to Norbie's 2JZ, my wireup probably had 30-50 additional wires (by no means having a go at Norbie - just different people do things differently [his was a lot more time efficient ]).

    Best thing I can suggest (as jon has suggested), get hold of a wiring diagram, pull the engine bay and chassis looms apart without cutting wires, leave the engine loom intact unless you want to modify/retape/reloom it and have a play by identifying circuits and systems. You would then be in a position to ask more specific questions that could hopefully be answered by people who have done conversions involving UZS131s.

    Mos.
    Last edited by Mos; 26-08-2006 at 03:32 PM.
    Admin, I.T., Founding Member, Toymods Car Club Inc.
    2000 IS200 Sports Luxury 1UZ-FE VVTi, 1991 MX83 Grande 2JZ-GTE (sold)

  5. #5
    Toymods V8 Member Too Much Toyota CrUZida's Avatar
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    Default Re: Wiring Experts! Seperating looms for engine swaps?

    Yes, the alternator wiring is part of the body loom, not the engine loom, but I'd say your factory setup is the same as this, so that doesn't matter.
    Peewee
    1985 MZ12 Soarer - 1UZ Powered
    2013 86 GTS

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    ......... Carport Converter jeffro ra28's Avatar
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    Default Re: Wiring Experts! Seperating looms for engine swaps?

    Thanks for your replies everyone!

    I figured i was hoping a little to hard for someone to tell me that "You only need the left side of the loom". Which Norbie has basically told me but in a slightly different case.

    The main thing i dont want is to have a ginormous fuse panel intended for the entire electrical circuit of a whole car and only use the engine related fuses.

    Could someone please tell me what ECT stands for. I wikipedia'd it and it says electronic control transmission??? Sounds about right to me.

    I will continue to nut it all out! i have already sliced half my thumb off seperating un-nesasary wires from the loom!

    Thanks everyone for your help!

  7. #7
    Junior Member Backyard Mechanic jonra23's Avatar
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    Default Re: Wiring Experts! Seperating looms for engine swaps?

    Yes Electronicaly Controlled Transmission.

    When you get all the wires that you dont need you will find there is probably only 3 or 4 extra fuses that you need over the RA28s original wiring.

    Not sure if you have wiring diagrams, http://www.lextreme.com/lexecc1.pdf and http://www.lextreme.com/lexuecc2.pdf may help if you dont.

    Buy yourself some decent side cutters, automatic wire strippers, small/medium soldering iron, shrink wrap and enjoy.

    regards
    jon

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    toyota-less Carport Converter skiddz's Avatar
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    Default Re: Wiring Experts! Seperating looms for engine swaps?

    mos and john you are both exactly right

    in my old exa i labeled every engine plug pulled the engine out layed all the wiring on the floor and established what i did and didnt need,

    well because the ecu controls the transmission, all you need to do is take the engine harness and everything else associated with the ecu,

    for the tacho either take it from the coil or the ecu (not 100% sure how the 1uz works), check a wiring diagram to find out which wire if it is ecu, if its coil run a wire from negative (??) and modify your tacho accordingly (got twice the cylinders now), if its an electronic speedo then you may have more problems that i can anticipate...
    2T out 4A in....

    4A out 3VZ in. 3vzfe rebuild, RWD-ising, and conversion for ta22

  9. #9
    Junior Member Backyard Mechanic jonra23's Avatar
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    Default Re: Wiring Experts! Seperating looms for engine swaps?

    Tacho for a 1uz-fe into an RA28 is going to be ok, just run it of one of the coils as it has 2X4cylinder distributors, will just need to convert square wave into a spike pattern. http://www.toymods.net/forums/showth...ht=diode+tacho

    There will be other little headaches though, now will have internal regulator rather than external regulator altenator.

    None of it is hard just need to be very methodical.

    regards
    jon

  10. #10
    Toymods V8 Member Too Much Toyota CrUZida's Avatar
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    Default Re: Wiring Experts! Seperating looms for engine swaps?

    1UZ uses normal ignitors/coil.
    Standard tacho will work fine.
    Peewee
    1985 MZ12 Soarer - 1UZ Powered
    2013 86 GTS

  11. #11
    Junior Member Domestic Engineer
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    Default Re: Wiring Experts! Seperating looms for engine swaps?

    to wire up a crown with 2 ecus will pro take u afew weeks on and off cause there is alot of wires that go between auto and engine ecu and they go round the bloody engine bay for no reason

    the auto ecu is ontp of glovebox i think

    to do it properly takes me 10 hours and i know 90% of them off top of my head

    that is turn key with all gauges working

    the other day i had a big spew at someone on the phone cause he kept ringing me asking questions on how to do this and that

    so i told him to fukin leave me alone

    and if he wants me to help him on the phone to deposit 500 bucks into my bank account

    and ill talk on the phone all day

  12. #12
    ......... Carport Converter jeffro ra28's Avatar
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    Default Re: Wiring Experts! Seperating looms for engine swaps?

    so what was your number again sideshow?

  13. #13
    Junior Member Grease Monkey
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    Default Re: Wiring Experts! Seperating looms for engine swaps?

    Watch it Jim, he might take you up on the $500 offer!

    Crown 1UZ's would be one of the most time consuming looms to do. My advice would be to get Jim to do it whatever the price.

  14. #14
    Toymods Pimp Chief Engine Builder Norbie's Avatar
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    Default Re: Wiring Experts! Seperating looms for engine swaps?

    Quote Originally Posted by Mos
    It depends what you want to do and how complete you want to make it. In contrast to Norbie's 2JZ, my wireup probably had 30-50 additional wires (by no means having a go at Norbie - just different people do things differently [his was a lot more time efficient ]).
    Mos makes an excellent point - you need to decide at the outset how far you want to go, and how much of the original car's circuitry you want/need. In my case I wanted the engine to start and run properly, and that's it - therefore the quick'n'dirty approach I described was quite adequate. Mos, being the perfectionist he is, clearly wanted much more than that so invested the time and effort integrating more of the new circuitry into the host vehicle.

    There's no doubt that Mos' car is more complete and a far better job overall, but at the same time my car starts and runs with zero issues - in other words, we both acheived our defined goals, as different as they were. Now you have to decide for yourself, what is your desired outcome? This will have a major impact on the best way to proceed from here.

  15. #15
    ......... Carport Converter jeffro ra28's Avatar
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    Default Re: Wiring Experts! Seperating looms for engine swaps?

    Ok well, thanks all for advice!

    The loom is now out and on the floor! Now i have the task of arranging all sensors and working out which things i need like cruise control sensors, tranny overdrive and key barrol etc.

    Then as adviced i will hook up sensors to loom and nut out what equals what!

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