7mgte swap gone wrong?

[jony89]

So after all my hard work I'm very disappointed in the results so far:nono:

To start off i swapped a 7mgte from a 88 with all the harness and body harness into my 89 NA car. I hooked up everything and it would crank but wouldn't turn on. I tested for spark and had none. I tested for signal the the injectors and got none either! But fuel does get to the rail.

Another problem i had was that the CEL, battery light, and a couple more lights would stay on without the key in the ignition! The fuel pump relay would also stay buzzing!
Then the craziest S%#$ happened!! The motor started cranking on its own!! Theres no key in the ignition it even cranks without the ignition switch connected!
So i can't even connect the battery or else it'll start cranking so its very very hard to diagnose the problem. Could i just have a messed up ecu.

Someone please chime in this is very frustrating and i need my car to get around now. :1zhelp:

 

[BloodRayne7M]

Did you make sure the CPS was timed correctly? As for all the electronics going crazy, you might have a short in the harness somewhere that is sending power directly to all the electronics and bypassing your switch.

 

[MightyAl]

You need to double check your wiring. 87-88 harness is different from 89. I am pretty sure the connectors are different.

Did everything plug in under the dash?

 

[ilikebigbutts]

check all grounds, going to engine and chassis.stuff turning on by themselves is usually a missing ground, voltage back.feeds through other circuits.

 

[jony89]

I did check my cps, i checked it like 3 times. The hole is alined with the notch and i actually move it a tooth so when it goes in it aligns the way it should.

I know the harnesses were different witch is why i swaped every harness in the car (pain in the butt) there was only two plugs i couldnt find were they belong. Could be a problem since its a big one under the steering column panel. I can send a picture of it if you pm me you number. Anyone?

And ill go through my grounds again

 

[jony89]

I have ground from the head to the chassis, battery to block, and another one down in the tranny to chassis. Would i need a separate ground from the block to the chassis? Or is the battery ground on the block good enough

 

[hvyman]

There is a ground in the harness that is supposed to be on the intake manifold.

 

[jony89]

Is it under it? If someone has a picture of that ground that would be great but when i put my harness on i dont remember any ground wire on the intake manifold. I have a feeling the owner of the donor car i bought for the swap did some bs hacking on the harness but since this is my first swap i dont know what a correct harness should look like. (if mine isn't hacked)

 

[hvyman]

It bolts to the intake manifold. Has 2 brown and 2 white wires on eyelets. Car won't run without them along with a bunch of other strange things.

They are also long enough to make there way to the starter or other places as well.

 

[jony89]

wow if im not mistaking i have a feeling that i mounted that on the starter with the batter power cable! it seemed right because like u said they are long enough lol, im thinking that explains my car cranking on its own when the battery is connected? I will check this tomorrow and if i am right im going to hate myselff forever hahah

 

[hvyman]

I haven't seen it do that. As it's a ground.

How did you hook the starter up. Should have 12 from battery on the post and a small connector that only gets 12v in the crank position.

 

[jony89]

What I did was I bolted the ground to the starter and on top of that I have tge 12v battery cable. This harness doesnt have the 12v cable wired up in it but let see if thats even the problem

 

[hvyman]

One is a little connector that is in the harness. The other is the big cable from the battery.

 

[supraguy@aol]

You bolted a ground on the starter, and then bolted 12volt from the battery...on TOP of it???

 

[jony89]

Yes and after I fixed that tge car wouldnt crank on its own the problem now is no fuel out the injectors

 

[ilikebigbutts]

last time I touched a supra was well over 5 years ago, so I don't remember if the wire going to the starter has a fusible link (most likely) or a fuse.most certainly you blew either one.check all fuses as well, efi fuse might be blown causing injectors not to fire.

 

[Grandavi]

12 volt to ground wire would close (fuse) the circuit wouldn't it? Hooking up the battery in that state would be a bad thing.. lol.

 

[hvyman]

Check to make sure the fuel pump is working.

Have you verified that there is 12v to the injectors or tested the circuit with a noid light?

 

[hvyman]

Check to make sure the fuel pump is working.

Have you verified that there is 12v to the injectors or tested the circuit with a noid light?

 

[jony89]

I might be lucky because surprisingly all fuses were still good hahah lucky me. But i got the car started today!!!!

So my noob problems were the ground and 12v were on top of each other. And the cps was off thats why the injectors weren't getting proper signal to pulse. Hey we all learn from our mistakes right? thanks to everyone who helped me on this I appreciate it a lot!