engine wiring harness changes in 89....anyone know?

[bizobsupra]

Just trying to figure out exactly when the mk3 changed the plugs on the wiring harness and moved the altitude sensor inside the ecu. i am swapping a 1987 7mgte into my 89, which was built in 11/88. i have been told conflicting things...for example that the 87 wiring hanrness and ecu should plug into my car because it was not manufactured in 1989...but then i am tave also been told if it was made 89 that i need a specific 89 harness and ecu. so basically what i am asking, is if anyone knows the specific difference is the wiring changes (different plugs and alt. sensor i think?) and when did they take effect? Any help would be greatly appreciated!!!

Thanks in advance!

Brian

[bgrieger]

89 is a bastard year. Toyota used up the old parts until they ran out, then switched over. There was no VIN at which it changed. In theory, you should be fine, given you have the 87 computer to go with the 87 engine, of course guessing you also have all the 87 accessories under the hood too (sensors etc). Clearly the 87 harness will hitch to the ECU, and if it matches the power plugs from the body, all should be well. Otherwise, you may have to do a little rewiring...

Now, if you are taking out a turbo motor, just swap over all the electrical to the 87 and use what you have.

BOb

[Jeeves]

If he's just swapping the engine, he should be fine. However, he'll want to retain his 89 harness. He'll also want to retain his intake manifold and his thermostat housing. I know for a fact that in the 88-89 transition the TPS style changed (don't think the plug actually did though) and I know that the sensors on the thermostat housing sensors changed slightly. Pretty much, plug it all in on the engine before you drop it in, and if something doesn't match, see if you can pull the part from the 89 engine and such.

Like BGrieger said, it's a bastard year, so it's really a grab bag. If you've got both sets of hardware 89Harness/engine and 87 Harness/Engine, you can't really go wrong.

[bizobsupra]

well, i do appreciate the input guys! I do apologize, however, for not mentioning that i am doing a non turbo to turbo conversion. I have been looking at the plugs in the body harness that go to the wiring. im not sure...someone told me the newer style plugs are round? Parts are not a problem, i have the complete 87 supra. I wish it was as nice as my 89 (22,342 miles) and flawless, but it isnt so i am forced to do the swap More so volunteered lol. Im gonna yank the glove box of the 87 and compare the plugs, looks like that might be the only way to tell before i put it in and get pissed. Ill keep you guys updated! Thanks!

[Jeeves]

Newer style is just different, here's for reference:

1986.5 -> 1988 Turbo (7M-GTE) Plugs:
[img]http://**********s.com/gallery/d/11719-1/pre89ecu.gif[/img]

1989+ Turbo (7M-GTE) Plugs:
[img]http://**********s.com/gallery/d/11717-1/post89ecu.gif[/img]