7MGTE swap cranks but won't start - Please Help!

MA70_Powa

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Jun 17, 2007
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Tasmania
Hi guys,

I'm almost the whole way through a 7mgte swap into my 86.5 n/a auto (well, my mechanic is, anyway :)).
I got the engine fully rebuilt, and its all wired up (except the dash for the moment, but it has been connected in the past and works) ready to go... only problem is, it doesn't.

The car cranks over fine, but won't start. It has no injector pulse or spark.

I'm using an 89 harness, an 89 ecu and a 90 7mgte. I've got all grounds connected, everything that needs power is getting power, and the plugs which differ between pre and post 89 have been rewired.
NO I'm not gonna get a pre 89 harness as there arent any. I've looked. Plus it's cost me waaaay too much already.

Now before anyone suggests it, yes Ive got a new cps and a new ecu (still 89) and timing is right (as far as I'm aware).

The weird thing is, when you crank the engine over by hand there is injector pulse and spark, but as soon as you try it with the key it disappears.
Also after trying this for a few minutes the ecu starts to smell and get warm, which isn't good - this leads us to believe that there may be a short or fault in the harness somewhere...

What do you guys think?

If there is a short in the harness... how would we go about finding it?
If there's anything else it could possibly be, suggest away :D
Because this seems like a very weird problem...

Any help would be greatly appreciated as this has dragged on for months and it's driving me nuts!
 

ForcedTorque

Join the 92 Owners Group
Jul 11, 2005
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Satsuma, Alabama, United States
You can jump two connections in the diagnostic block to verify that your fuel pressure is working. Cygnus is not working, and my TSRM is in my car out in the rain. I think it's FP and +B, but could be wrong. I'll correct this as soon as I can if wrong.

You mentioned not having the dash hooked up. There is a big square plug near the ECU that you will have to plug up before it will crank.
 

MA70_Powa

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Jun 17, 2007
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Tasmania
Oh do you have to have the dash hooked up for it to start?
Although It cranks with and without the dash hooked up and the same things happen
 

suprahooked

Built 7M
Jun 20, 2006
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Is the igniter bolted down ? It is grounded through the case. Check your codes and if you dont know how it is in my sig. next line down.
 

MA70_Powa

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Jun 17, 2007
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Tasmania
i see... I was sure I'd seen someone get it to work tho. Hmm... Gotta hunt one of them down then.

*EDIT* found one interstate so I'll see how I go once it arrives.. hopefully thats the only problem :)
 

MA70_Powa

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Jun 17, 2007
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Tasmania
Yep thats right, my distributor's in the bin :)

Although my mechanic *did* say that he tried it with the distributor just in case but the same thing happened.
 

MA70_Powa

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Jun 17, 2007
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Tasmania
Ok I got it running! :D
I managed to get an 88 harness out of a fresh halfcut a shop got it only a few days ago, along with the new igniter.

Only thing now is that the idle is a bit funny.. maybe timing is off? although I won't know for sure for a while because my bloody turbo died :( stupid thing only lasted 5 minutes!

Anyway cheers for the help guys, I'll be sure to start a build thread soon too :)