Hachi-ichi Posted April 11, 2020 Share Posted April 11, 2020 Yo OS, I'm having a go at making this lockdown productive, but i've hit a wiring wall.. Recently performed an engine swap into one of my cars and of course I've reach the wiring dilemma. The swap is: Full 1986 GA70 1G-GEU (Bluetop MAP sensor) & Auto trans into a... 1986 GX71 Cresta Super Lucent (Factory Map sensor 1G-EU & auto). The engine is a 100% runner (had it running myself 1 day prior to pulling it) The Supra was 100% complete and I've used: Engine loom (uncut and NOT damaged) Trans ECU All accessories Everything has been plug and play, however, I understand that the 1G-GE won't run without some (repinning?) wiring work in the 1G-E Cresta. I did try start the car knowing it wouldn't fire, however the starter motor constantly triggered once the key was turned to ON (even before getting to start). As it sits complete now. . . There are TWO remaining plugs not used currently. One of them (pic below) is attached to the 1G-GEU engine loom and does not have a mate on the GX71 body loom. On the GA70 supra, the other end of the plug goes straight to the fuse box. . . The second plug not used is attached to the body loom of the GX71 and is a yellow 6 pin plug. on the factory 1G-EU engine loom, the other end of this plug is present. We continuity tested this plug on the 1G-EU engine loom and it went to 1G-EU ECU pins: BATT; +B; +B1. . . . . Has anyone had any experience with twincam 1Gs into single cam bodies? I have done a bit of a search on here and found some helpful stuff, however most stuff is for other chassis / example and I'm having trouble correlating tips / troubleshooting to my car. Any help or advice on here would be hugely appreciated. Cheers, Quote Link to comment Share on other sites More sharing options...
Carsnz123 Posted April 13, 2020 Share Posted April 13, 2020 I'm doing a similar swap into my GS126V except both engines are AFM rather than MAP. The conclusion I came too is that the single cam cars run a different body loom to the twin cam cars. I've resigned myself to the fact that it will require some cutting and splicing of looms to get power where it needs to go there is only a handful of wires that need either constant or switched power. All be it I haven't touched the car for a couple years. Too many projects. This has some useful info if you haven't seen it already https://bluetwentyeight.wordpress.com/tech-docs/ 1 Quote Link to comment Share on other sites More sharing options...
Spencer Posted April 13, 2020 Share Posted April 13, 2020 Ah yeah you shouldnt have plugged all that in and just hoped it works. The ECU's and body looms will have different ways of powering things, you could be poking 12V into things that shouldn't have it and fry them. Really should have done a full forensic check of how the existing all works and what wires do what and then match that to pin-outs for the 1gge. I figure the main relay shit will be different which is always a trap on this era of Toyotas, the ECU switches power for a bunch of things (idle control, maybe injectors etc) its not switched off the key. 1 Quote Link to comment Share on other sites More sharing options...
thegreatestben Posted April 13, 2020 Share Posted April 13, 2020 Pinouts are usually printed on the board in my experience if you dont' have luck with diagrams. 1 Quote Link to comment Share on other sites More sharing options...
Hachi-ichi Posted April 14, 2020 Author Share Posted April 14, 2020 Have dug into the forensic checking of each loom. Def shouldn't have cranked it.. First thing I found when looking at both ECU pinouts was that 1G-EU doesn't have an ISCV or M-REL pin in the ECU. Looking at the link below and having seen the twincam ECU, it's apparent that M-REL needs to be wired. I found it in that spare plug on the 1G-G engine loom and continuity tested it to the ECU. In the supra, the M-REL wire goes to the fusebox (main relay). http://wilbo666.pbworks.com/w/page/42947521/M-REL - 6 Wire Idle Speed Control Valve (ISCV) Wiring The other yellow 6-pin plug contained pins that trace to the 1G-EU ECU pins: BATT, B+, B+1 which go through the fusebox as well (found from cont testing). In short, both plugs in the pics above contain the same wires minus the M-REL pin on the body loom side. I also checked with someone who has a factory twincam GX71 and his engine loom also has the same 6-pin yellow plug with the same wire colours and locations. Quote Link to comment Share on other sites More sharing options...
Hachi-ichi Posted April 14, 2020 Author Share Posted April 14, 2020 Also, i'm not sure if it's worth noting. The fuse boxes on both cars are identical part numbers and contain the same number of relays and fuses. Continuity testing both showed them be apparently identical in their function too. The only additional part seen in the Supra fusebox contains the headlight fuse (pop ups). Quote Link to comment Share on other sites More sharing options...
thegreatestben Posted April 14, 2020 Share Posted April 14, 2020 I wouldn't be suprised if they changed some of the pinouts. If you're lucky you haven't fried anything and you might just need to repin a couple things. Quote Link to comment Share on other sites More sharing options...
Stu Posted April 14, 2020 Share Posted April 14, 2020 Ive wired a couple of these over the years - will dig out my notes. 2 Quote Link to comment Share on other sites More sharing options...
Hachi-ichi Posted April 14, 2020 Author Share Posted April 14, 2020 Just now, Stu said: Ive wired a couple of these over the years - will dig out my notes. Appreciated Quote Link to comment Share on other sites More sharing options...
Hachi-ichi Posted April 15, 2020 Author Share Posted April 15, 2020 Also figured out today that I'm using an A43DE and not the standard A42DL. Means I'll have to wire in the trans ECU from the supra in order for the trans to function normally. http://www.supras.org.nz/techinfo/TSRM/15_AT.pdf Found a wiring diagram on here so doesn't sound too difficult. I have the supras dash loom to pull it out and isolate the ECT stuff. I also made a pinout for the engine loom to dash plug so I have clarification on all the pins. 1 Quote Link to comment Share on other sites More sharing options...
HighLUX Posted April 17, 2020 Share Posted April 17, 2020 I have this diagram @Stu did when he modded a 1g loom for me which could be helpful even though its for a AFM 1GGE and this book which I could get some info from if needed 1 Quote Link to comment Share on other sites More sharing options...
Hachi-ichi Posted April 18, 2020 Author Share Posted April 18, 2020 Thats actually gold, it more or less confirms my current setup, the BATT, x2 +B, IG/SW and M-REL are all wired correctly now, so I take it my ECU is powered correctly. I traced all wires in the dash - eng loom plug in both cars and there is some repinning to do. Thats all somewhat ez and I can do, however getting this A43DE in here is a fuck around. The A43DE with 1G-GEU in supra uses a seperate trans ECU which the A42DL equipped body loom doesn't have. I have the supra still here so I'll isolate the ECT shit and attempt to get it in the Cresta. Ideally this is the time where auto goes in bin, but its lock down and I want to get it running. Quote Link to comment Share on other sites More sharing options...
Stu Posted April 19, 2020 Share Posted April 19, 2020 Yeah thats the notes I was going to find for you, there might be a few more bits and pieces, will be able to get to them tomorrow 2 Quote Link to comment Share on other sites More sharing options...
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