1991 7MGTE to 1987 7MGTE

bobo4life · 07-07-2010, 03:55 PM

I have a problem. I work at a shop and we have an interesting combination of elements here. I have a 1991 Supra Turbo with an engine MT and ENGINE wire harness that came out of a 1987. THe owner gave up on trying to figure this out, and now its in our lap. I'm wondering if anyone can give me some advice. I'm seeing from difference in the wiring diagrams that there are major differences all around as far as routing and pin configurations. First of all, does anyone know if it will work out? Secondly does anyone know if the ECU is ok to use- mine has the part# 89661-14260 (which from other forums shows to be a 1989 part number which came with the 1991 car). What I need to do is make it run. There are a couple connectors under the dash for the ECU harness and engine harness that are different (some wires at different pins, some not even there on one side or too many on the other). I have a set of connectors to start switching stuff over, but there's missing wires or extra wires that between both diagrams show them going different ways. I'm really frustrated at this thing, and don't even know if it will work. Anything you can advise would be appreciated.

Supra Saiyan · 07-07-2010, 04:59 PM

Just tossing this out there.. I have only a slight knowledge of the actual mechanics of cars. Is it possible that the car got its wire harness from japan and its just different than a US one? Do you know if the 1991 engine was actually a swap from the original? those would be my 2 guesses at it. I would have thought they where

interchangeable

.. Is this 87 7MGTE from japan?

bobo4life · 07-07-2010, 06:46 PM

The engine that blew came with the car and it was a US car, and the engine that went in was a scrapped engine from a boneyard which came out of an 87 US car (as far as the owner knows). I'm looking around for wire harnesses and possibly an ECU, but I don't want to buy them without needing to.

btwilson86 · 07-07-2010, 06:53 PM

Did they swap anything else over from the 87 Supra? Such as the fuel injector resistor packs on the firewall? I'm assuming that since the 87 harness is still connected that they kept the 87 fuel injectors and fuel rail...

If I was in your situation, I'd get the fuel injectors and wire harness from a 89+ turbo supra. That way the factory gauges will operate properly and it should just be plug and play. If a wire harness is hard to find, you can get a 87 ECU, 87-88 Gauge cluster + dash harness, the resistor packs for the fuel injectors, and maybe some other odds and ends to get it running right.

I'm sure it's possible to rewire the connectors on the wiring harness to make it connect to the ECU properly, but you will still need to address the fuel injectors. pre89 7MGTE's use low impedance injectors, whereas 89+ used high impedance injectors (I think that's right, might be the other way around though; trying to recall from memory).

Anyway, help this gets you pointed in the right direction.

batmmannn · 07-07-2010, 06:59 PM

Sounds like a real headache, Glad I'm not attempting it. By the time I had it figured out and picked enough brains I would have wasted more time than the car was worth.... But that's just me.

cre · 07-08-2010, 02:55 AM

All years 7M-GTE used low impedance injectors. Only 7M-GE's saw that change.

blake · 08-03-2010, 02:32 AM

i have a 91 supra and it is a na, and im at the same problem, well im building it. i bought an 88 supra and i found out the harness is different and all. if u can what u figure out post so i can go over the info so i can then save time myself.. i know it is a pain in the rear...

Supra Saiyan · 08-03-2010, 02:40 AM

http://www.4cefed.com/conversion.html

Green7mgte · 08-03-2010, 02:42 AM

god thats the 5th time i seen that link end a thread..

Supra Saiyan · 08-03-2010, 02:45 AM

Thought blake would need it so don't go buying stuff that's not compatible with one of his 2 supras..

lol, that's funny you have seen the link ho'd out like that..

07-07-2010, 03:55 PM	#1
bobo4life Stock Join Date: Jul 2010 Location: CT Posts: 2	1991 7MGTE to 1987 7MGTE I have a problem. I work at a shop and we have an interesting combination of elements here. I have a 1991 Supra Turbo with an engine MT and ENGINE wire harness that came out of a 1987. THe owner gave up on trying to figure this out, and now its in our lap. I'm wondering if anyone can give me some advice. I'm seeing from difference in the wiring diagrams that there are major differences all around as far as routing and pin configurations. First of all, does anyone know if it will work out? Secondly does anyone know if the ECU is ok to use- mine has the part# 89661-14260 (which from other forums shows to be a 1989 part number which came with the 1991 car). What I need to do is make it run. There are a couple connectors under the dash for the ECU harness and engine harness that are different (some wires at different pins, some not even there on one side or too many on the other). I have a set of connectors to start switching stuff over, but there's missing wires or extra wires that between both diagrams show them going different ways. I'm really frustrated at this thing, and don't even know if it will work. Anything you can advise would be appreciated.

07-07-2010, 04:59 PM	#2
Supra Saiyan 3" Exhaust Join Date: Feb 2010 Location: Oregon Posts: 225	Just tossing this out there.. I have only a slight knowledge of the actual mechanics of cars. Is it possible that the car got its wire harness from japan and its just different than a US one? Do you know if the 1991 engine was actually a swap from the original? those would be my 2 guesses at it. I would have thought they where interchangeable.. Is this 87 7MGTE from japan?

07-07-2010, 06:46 PM	#3
bobo4life Stock Join Date: Jul 2010 Location: CT Posts: 2	Not too sure, but almost positive.... The engine that blew came with the car and it was a US car, and the engine that went in was a scrapped engine from a boneyard which came out of an 87 US car (as far as the owner knows). I'm looking around for wire harnesses and possibly an ECU, but I don't want to buy them without needing to.

07-07-2010, 06:53 PM	#4
btwilson86 Super Moderator Join Date: May 2007 Location: Billings, Montana Posts: 1,034	Did they swap anything else over from the 87 Supra? Such as the fuel injector resistor packs on the firewall? I'm assuming that since the 87 harness is still connected that they kept the 87 fuel injectors and fuel rail... If I was in your situation, I'd get the fuel injectors and wire harness from a 89+ turbo supra. That way the factory gauges will operate properly and it should just be plug and play. If a wire harness is hard to find, you can get a 87 ECU, 87-88 Gauge cluster + dash harness, the resistor packs for the fuel injectors, and maybe some other odds and ends to get it running right. I'm sure it's possible to rewire the connectors on the wiring harness to make it connect to the ECU properly, but you will still need to address the fuel injectors. pre89 7MGTE's use low impedance injectors, whereas 89+ used high impedance injectors (I think that's right, might be the other way around though; trying to recall from memory). Anyway, help this gets you pointed in the right direction. __________________ 1989 7MGTE R154 Targa Top White Package w/Blue Interior Driftmotion 57trim CT26, Upgraded Intercooler, 2.25" Hard Pipes, 3" Turbo Back Exhaust with Test Pipe, HKS VPC w/GM 3 bar MAP sensor, APEXi S-AFC, Walbro 255lph fuel pump, ProSport EVO Series Boost / Fuel Pressure / AFR gauges, Lotek a Pillar Gauge Pod, HKS Type 0 Turbo Timer, Eibach Lowering Springs, Tokico Illumina II TEMS struts, custom powder coated Motegi Racing TrakLite wheels

07-07-2010, 06:59 PM	#5
batmmannn 12psi boost Join Date: May 2010 Location: West Virginia Posts: 320	Unnngh Sounds like a real headache, Glad I'm not attempting it. By the time I had it figured out and picked enough brains I would have wasted more time than the car was worth.... But that's just me. __________________ 1987 N/A 7MGE Left Hand Drive MK3 Red 5 Speed and Black Auto Supras My Next project is the Batmobile!

07-08-2010, 02:55 AM	#6
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	All years 7M-GTE used low impedance injectors. Only 7M-GE's saw that change. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

08-03-2010, 02:32 AM	#7
blake Stock Join Date: Jun 2009 Location: loxley, al Posts: 16	same project i have a 91 supra and it is a na, and im at the same problem, well im building it. i bought an 88 supra and i found out the harness is different and all. if u can what u figure out post so i can go over the info so i can then save time myself.. i know it is a pain in the rear...

08-03-2010, 02:40 AM	#8
Supra Saiyan 3" Exhaust Join Date: Feb 2010 Location: Oregon Posts: 225	http://www.4cefed.com/conversion.html

08-03-2010, 02:42 AM	#9
Green7mgte Supra Forum Moderator Join Date: Nov 2009 Location: Green-Ohio Posts: 1,297	god thats the 5th time i seen that link end a thread.. __________________ 92 Ma71 7mGTE Auto. SafcII Supra FAQ Supra MKIII FAQ Classified Section guidelines :

08-03-2010, 02:45 AM	#10
Supra Saiyan 3" Exhaust Join Date: Feb 2010 Location: Oregon Posts: 225	Thought blake would need it so don't go buying stuff that's not compatible with one of his 2 supras.. lol, that's funny you have seen the link ho'd out like that..

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