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Discussion Starter · #1 ·
I've tried to search the forums for my question but was unlucky in find in results. Backstory here is I have a 1989 supra with a 7mge in it that has rodknock from he**. I had a buddy who had a 7mgte that I'm going to build and swap in. But in the mean time I still wanna drive the car. I stumbled across another 7MGE from a 86 Supra for only $75! Question is, will the connecters on the engine harness be the same? He said something about it having yellow plugs, will this make a difference? Figured I'd turn to people who have more experience in this field.
 

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Just transfer all the sensors, and the distributor from your engine to the older one, use your ECU, harness, sensors, etc..
I didn't even think of that! But otherwise they're pretty much the same internally right? I know the engine mounts are different but I've got that figured out.
 

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Yellow plugs? Do you mean yellow set of fuel injectors? Like 700cc yellow injectors?

If im not wrong and he is talking about injectors then you wouldn't be able to run the engine without having a ECU tune, or a upgraded MAF to compensate for the extra fuel. Honestly if he was running different injectors then idk how the engine ever ran without him having some kind of aftermarket ECU.

I would look into a few things when buying this or any engine. Does it run? Does it have compression? Are you buying it on a crate or in a car?

 

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He's also probably referring to the wiring connectors in general too. Every so often Toyota would change the wiring harnesses and the plug ends i.e. connectors would change shape from one year to the next even though the engine was essentially the same. You might have to transfer the sensors from one engine to the other so you can connect them but, that's probably about it. My 91 7MGTE would have a different harness than an 86 or 87 but the engine is the same internally.
 

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yellow plugs (pre 89.5) and the gray plugs (89.5+) are the exact same and really only tell you about the engine mounts.

EDIT: Apparently the ECU plugs are different but the body plugs are the same :) My bad
 

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Funny, when I was importing HUNDREDS of HKS F-con and VPC units, and harnesses out of Japan,
the early & late plugs were completely different.
Must be when people born after I owned my first 7M, look at an ECU connector plug, reality changes.
 

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Funny, when I was importing HUNDREDS of HKS F-con and VPC units, and harnesses out of Japan,
the early & late plugs were completely different.
Must be when people born after I owned my first 7M, look at an ECU connector plug, reality changes.
My car had gray plugs and I pulled the connectors off of a yellow plug supra (from a junkyard) and they were the exact same. I used them on my 1JZ swap so I didn't have to cannibalize my old harness off of my 7mge. But I only used the body connectors and didn't look at the ECU plugs and assumed that they were also the same. Being passive aggressive isn't very friendly :)
 

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That's me, not very friendly...
haha you make up for it by actually knowing what you are talking about.

this is not a hard question.

physically...you can take any year 7mge and mount it in your car. then use your wiring harness and it will all connect up. it does not matter what year the donor engine is from --think about it, you have a 100% complete car you are starting with. then you buy a replacement engine. it could be a short block, a long block, complete with manifolds and wiring. anything on that engine that does not match you can unbolt and put your cars part on
you can even use a 7mgte motor, bolt your intake and injectors up, put your distributor and exhaust on it and run it. not like its lower compression is going to make a na any slower lol. physically the engine parts are 100% the same (block and head, all years, na/turbo. yes there are slight variations, oil sprayers etc but it all bolts up....)

electrically, its a different story

86.5-88 NA ECU are different than 89-92

california cars also have different ECU with external connector dongle (HAC high altitude connector)

7mge NA injectors are yellow

why is there all this mis-information packed in one thread uff
 

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No, they are talking about Yellow ECU plug.

Who in hell would even think about using Chinese injectors.........
yellow plugs (pre 89.5) and the gray plugs (89.5+) are the exact same and really only tell you about the engine mounts.
Huh, I didn't know any of this. Interesting to know more was done around the time of the face lift. I was planning on buying a Megasquirt 3 Plugin-Play in a few years so now I'm wondering if the JDM and USD plugs are different like they are on the MR2. Considering I have a 1990 JDM supra with JDM motor/ECU; I hope I don't have to repin the harness like my friend did

And for the fuel injector thing. My buddy was always talking about getting different colored plugs implying that injectors were color coded for flow rate. After I did 2 seconds of research I found the injectors which I posted; alongside those I saw the yellow plug ECU but I didn't think there were any differences because it was still a 7mgte.
 

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Unlike some other Toyota ECUs, like a 4AG, the 7M plugs are the same pin-outs, providing you have the correct vintage (early/late), and not trying to use a turbo ECU on a NA.

But Mega-Dribble?
I can do more with a stock ECU, S-AFC, and wide band, without worrying about a complete programing ordeal.
If you are serious about performance, and need a stand alone, get something like an Infinity.
 

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yellow plugs (pre 89.5) and the gray plugs (89.5+) are the exact same and really only tell you about the engine mounts.
No, no, no and no. Different plugs with different pin arrangements. Grey =/= Yellow.

87-88 ECU Pinout.jpg 89+ ECU Pinout.jpg
 

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No, no, no and no. Different plugs with different pin arrangements. Grey =/= Yellow.

View attachment 236911 View attachment 236913
When it comes to Yellow vs Grey harness, is it just a matter of repining the connectors? IE: Car has a grey connector harness, and I have a donor ECU with Yellow port, if I also had the Yellow harness plug connector could I simply re-pin it?
 

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Such unnecessary confusion:

7MGE: yellow and gray ECU plugs are identical. Plug and play.

7MGTE: yellow and gray ECU plugs are completely different. Not even remotely plug and play.
 

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Zooks, so just for clarity:

7MGE: yellow and gray ECU plugs are identical. Plug and play. (Identical within all years 7MGE meaning all 7MGE harnesses are compatible?)

7MGTE: yellow and gray ECU plugs are completely different. Not even remotely plug and play. (Yellow is different from gray 7MGE, or also different between yellow/gray on 7MGE?).

More a point of order here, vs really needing to know personally....
 
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