(MKIII) Beginner, Pulling 7MGE Engine - Help Request Thread!

mnmlst

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Apr 22, 2014
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edmonton AB
Hey Supramania, first time poster.
I have had a lovely MKIII for about a year now with a blown 7MGE. It's completely seized and I can't turn the crankshaft.

I want to swap in a 7MGTE (which I have on the way)

I am a beginner to most mechanical work but I want to do this myself to build some knowledge for future work.
I have a lot of questions,

My first question is, in order to pull the engine while leaving the transmission in, what should I unbolt and/or leave bolted from the tranny?
Also, will I need to drain my transmission fluid/oil pan to pull out the engine?

Thanks, I hope someone can help me along the way.

Here's my supra in its current state:
20140610_185402_resized.jpg
 

suprarx7nut

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Nov 10, 2006
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First comment may be db, but here it goes. Are you sure you have enough space in the front of that garage bay for an engine house holding up the engine?

Secondly, there's an excellent page on 49 easy steps to engine removal. Search for that and follow it.

Glad to hear you're diving in to learn, that's the best way.

Read up on that writeup and come back here with any specific questions.

Sent from my Moto X.
 

mnmlst

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Apr 22, 2014
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edmonton AB
Pretty sure if I move the car back/turn it a little, should be NP with a cherrypicker hoist.
Step #2 of 49 says crank the engine over. My starter wont even click. The wire from it appears very melted! Should I replace the wire and try to turn it over?
I have removed a few parts from the head of my 7MGE such as manifolds/tubes/distributor cap, is it too late to turn the key?
 

suprarx7nut

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mnmlst;2009978 said:
Pretty sure if I move the car back/turn it a little, should be NP with a cherrypicker hoist.
Step #2 of 49 says crank the engine over. My starter wont even click. The wire from it appears very melted! Should I replace the wire and try to turn it over?
I have removed a few parts from the head of my 7MGE such as manifolds/tubes/distributor cap, is it too late to turn the key?
I've had mixed results with that crank trick. at this point in your project, I'd ignore it. you can normally break it loose with a breaker bar (NOT a ratchet) and a cheater. I've done a few 7ms with just my breaker bar and jack handle as a cheater bar.

put the car in 5th, e brake on and protect your fingers/toes while you push/pull like hell.

I had one engine that I bought by itself already out of car. crank bolt was still on and I couldn't get it off. I paid a mobile mechanic with an impact to drive to my house and crack it loose with his pneumatic impact. cost me $40 and motivated me to get my own compressor and impact.

either way, you've got options.

Sent from my Moto X.
 

suprasick

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Mar 17, 2006
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mnmlst;2009964 said:
My first question is, in order to pull the engine while leaving the transmission in, what should I unbolt and/or leave bolted from the tranny?
Also, will I need to drain my transmission fluid/oil pan to pull out the engine?

I've found it alot easier to keep the trans attached as it aids the the proper exit and enter angle of the engine. Once you pull the yoke out of the transmission be ready for oil to come out. I would highly recommend you drain it first.
 

mnmlst

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Apr 22, 2014
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edmonton AB
Thanks alot for the responses.
Is it really worth leaving the transmission attached just to pull the engine at the nice angle?
I'll need an engine stand to take the tranny off the block after hoistin it, yea?


OK I'll try the breaker bar.
What size compressor do you have there, suprarx7nut?
 

suprarx7nut

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Yes worth leaving trans attached. You need to remove the trans from the engine before the engine can go on the stand.

My compressor is tiny and not very effective. Its 2 gallons and under 1scfm. I'd aim for 3scfm or more for an impact wrench.

Sent from my Moto X.
 

mnmlst

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Apr 22, 2014
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edmonton AB
I got a 19 dollar breaker bar today, got the cranknut off but couldnt turn the shaft one bit, I'm not even going to try to get it to TDC, must be fused together in there

took the intake stuff off, though, tempted to just take the whole engine out piece by piece :p
20140613_171504_resized.jpg


Soon, my shipment will arrive and I'm going to have an unbuilt 7MGTE in my garage, and I'm going to have some trouble putting it together, and finding all the right hoses/connections.
Is there a reliable, relatively expedient resource to find Wiring harness/ pipes/hoses/connector stuff for my new engine?

Sorry for my ultimate lack of knowledge
 
Last edited:

pogoism9

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Your GE harness would be OK to reference in some areas but not others. The better way to do it would be to find a second hand GTE harness that is year appropriate for your model year car (not the GTE year) and use that. On the upside if you are an electrician you can make repairs to a second hand harness fairly easy.

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mnmlst

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Apr 22, 2014
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I have a question about the wiring harness...
There are an assortment of 4 wire, 2 wire, 6 wire clips etc. that connect to various things around the engine..
Can I replace these clips with a soldered connection of my own making, or should I try to find the right sized clip for each thing?

For example.. For a 3 wire clip that has 3 wires going in to each end, can I splice all 6 wires together or do I need to have each specific wire going into the correct pin terminal?
Hope this makes sense. Thanks!

Also: My supra is 1986. Do I need an 86 turbo ECU or will the 87-90 ones work as well?
I FOUND A GUY selling 88 GTE wiring harness, WILL THIS WORK IN MY 86.5?!
 
Last edited:

pogoism9

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Find the appropriate clips. You will best be served getting an 87 or 88 harness. There was no turbo in 86

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suprarx7nut

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mnmlst;2010516 said:
Just an update I am going to build my own wiring harness for the new 7mgte..
Any light you can shed on this?
Should I try and use my 7MGE harness as a reference, or just try to follow the TSRM diagrams as best I can?
Can I use any sort of connectors or do I need to use specific ones for my MKIII?

Thanks for reading

EDIT: I am an electrician, I know this is within my abilities; still green when it comes to car mechanics/electronics though.

Building your own harness is a HUGE task. Much larger than the swap itself. You need to source a TON of hard to get connectors and terminals, not to mention buy a good crimper (NOT the ones at Home Depot). My harness build took dozens of hours and over $1200. You could do it a little cheaper, but it's a huge task for somebody not already very familiar with the engine/chassis.

I'd advise caution before attempting this. Building a wire harness from scratch is not a beginner task. If you mess it up it will be very difficult to troubleshoot. There are hundreds of wire terminations and getting one incorrect could keep the car from running.

mnmlst;2010542 said:
I have a question about the wiring harness...
There are an assortment of 4 wire, 2 wire, 6 wire clips etc. that connect to various things around the engine..
Can I replace these clips with a soldered connection of my own making, or should I try to find the right sized clip for each thing?

For example.. For a 3 wire clip that has 3 wires going in to each end, can I splice all 6 wires together or do I need to have each specific wire going into the correct pin terminal?
Hope this makes sense. Thanks!

Also: My supra is 1986. Do I need an 86 turbo ECU or will the 87-90 ones work as well?
I FOUND A GUY selling 88 GTE wiring harness, WILL THIS WORK IN MY 86.5?!

Soldering connections where connectors currently exist? Absolutely not. You need connectors that can be easily removed/interchanged. Finding these correct connectors is one of the hard parts of building your own harness. Keep in mind that you will need to swap some parts out in the future. If you built a harness with your own custom set of connectors no new parts would plug in like they are supposed to. It would be a nightmare every time you need to replace a component.

For everything to work you'll need an 87-88 ECU and harness. You'll also need the altitude compensation sensor.

Look around the forums for those items for sale. You should be able to find a complete harness and ECU for a reasonable price. You're much better off working with a decent harness than building one fresh.

FYI: When I built my harness I had TWO complete harnesses I used as donor harnesses. One was nearly new. IMO, without the donor harness you will stand no chance of making the harness correctly. You're better off just buying a used harness that's in decent shape and repairing as needed.
 

mnmlst

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Apr 22, 2014
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edmonton AB
There's someone in my city willing to sell me 1988 5spd turbo ECU and Engine Wiring Harness for 340$
Should work for me, right?
86.5 mkiii with 7mgte
 

pogoism9

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May 18, 2007
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88 would be perfect. As long as the harness is in decent shape, I believe 340 is fair for the pair. Make sure he gives you the high altitude compensation (HAC) sensor too. It connects to the small pigtail coming out of the 87 and 88 ECUs

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mnmlst

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Apr 22, 2014
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edmonton AB
pogoism9;2010560 said:
As far as pulling the engine, keep the trans on it when you pull. Its just easier in my opinion.

Thanks for the input. At what stage do I want to drain the transmission fluid?