87 7M-GTE Harness w/ 89+ 7M-GTE?

MA70witBoost

MA70witBoost

Registered Drifter
Jan 5, 2006
673
0
0
39
Hialeah, Florida, United States
www.theautolog.com
I have a brand new harness (yes, brand new... cost me $500+:3d_frown:) that I had gotten for my 87 7M-GTE. That motor is no good so Im buying a 91 7M-GTE w/ a built bottom end. I've heard that the 89+ 7M's are different. Less sensors if im not mistanken wich leads to a different harness (blue connectors as opposed to my yellow) and a different ECU.

I was wondering if its possible to use my harness (and obviously ECU) with the 91 7M and if so, how'd id go about doing so.

Also, are the harness, ecu, the only things that i'll have to worry about?
 
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Wayne G.

87Turbo 5sp Targa
Apr 19, 2005
213
0
0
Gainesville,Ga.
MA70witBoost;1024329 said:
I have a brand new harness (yes, brand new... cost me $500+:3d_frown:) that I had gotten for my 87 7M-GTE. That motor is no good so Im buying a 91 7M-GTE w/ a built bottom end. I've heard that the 89+ 7M's are different. Less sensors if im not mistanken wich leads to a different harness (blue connectors as opposed to my yellow) and a different ECU.

I was wondering if its possible to use my harness (and obviously ECU) with the 91 7M and if so, how'd id go about doing so.

Also, are the harness, ecu, the only things that i'll have to worry about?
Click to expand...

Stronger block/more reinforcment on the sides and the crank is fully counter
weighted and weighs a few lbs more - other than that they are the same.
The 87 ECU plugs should be Yellow and 89 and up are grey - I belive.
By the way I just got a new 87 5sp turbo harness from Champion Toyota (Jeff Watson) for $425.
 
Supra87T

Supra87T

2-Tone BLUE
Feb 23, 2006
135
0
0
Cincinnati, OH
I know cps and water temp sensor for sure. It's been a while but I have an 87 harness on a jdm 89+ 7M. You could also just change out the sensors if you didn't want to cut the harness to splice in connector. It was really fairly easy to do.

No HP loss, higher rev limit for 87 ecu.
 
H

Halsupramk3

Member
Apr 4, 2005
444
0
16
Mississippi
the water temp sensor plug is different on 89+. just switch out the sensor. i assume the pre89 and post 89 water temp sensors have the some volt output for the ecus. the cps plug is the same for all years. Its the O2 sensor plug that is different only on 91-92 cars. just use the 90 or lower o2 sensor. (91-92 sensor plug is square).

it is the body harness side by the ecu plugs that are different and of course yellow plug for 87-88 ecu vs grey plugs for 89+. the pin outs for these plugs are different or how the particular wires are arranged.

FACTS ON HARNESSES:
autos to 5 speed are specific as are n/a vs turbo specific
87 to 88 are the same.
89 has two different ones. transition year. some are yellow and some grey plug no air bag. one large square plug to the body harness will not fit on a 90 car. as it did not on mine. (90 T car to 89 T harness. one plug did not fit.) best to order with vin number or part number off old harness if they are available.
90 is a specific year and it has the white rectangle plug for air bag. i dont know if everything else will work if the white plug is left unconnected. u assume a 90 harness will work on a 91-92 car if you use the appropriate o2 sensor for the particular o2 plug. i dont know if there are any wiring diagram differences from 90 to 91-92
91-92 harness are the same.

you would have to rewire the pins from each different plug that did not fit to the plugs that did fit. so you would have to have a wiring diagram for each year. and good plugs to put the wires into.
 
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