97 cobra in 96 gt swap

[OKcobra]

Hey guys i hope you all can help me out. I finally got around to swapping my wrecked cobra engine into another mustang. I have been working this whole weeked swapping the engine and just now at 10 pm got done and was so pumped to start and nothing. Me and two other guys workeda total of 24 hours and got it done.

So here is where i need help, we tried to start it with the gt computer and the cobra computer and got nothing. all the lights, dash and stereo work. Any ideas???

We didnt change any of the dash or steering columns and both engines started fine in both cars before we tore them down.

 

[crash549]

that sucks. i'm sure you'll get it eventually. a big project like that is going to have a bit of trouble shooting involved. i'm not much help on motors though, sorry.

 

[KWClutch]

You'll need to bypass the PATS system. Just run an ignition wire. and cut off the PATS

 

[blackbob]

You're not going to be able to run the Cobra computer anyway. The pin-outs are different from ECU to ECU and the coils are wired different as well. Use the GT engine harness with the GT computer and coil pacs as well. transfer the GT coolant temp sensors over and extend that part of the harness. The GT ECU will work but will need a tune as it wont make much power or drive well-ish.

 

[BraMas]

I did the Identical swap 96gt with 97 Cobra engine. I had no problem with pats or starting. But I used the Cobra Engine Harness and ECM. Plugged the Harness into the firewall plugged ECM in and started right up.
Did you reattach the ground wire that is on the driver side of the block it goes from the chassis to the motor mount?

 

[whty98]

Did you use the GT or cobra engine harness?

I just did this swap a few weeks ago and I used the GT harness and everything worked fine, except I had to extend quite a few wires and swap the coolant sensors over. In retrospect, I should have used the cobra engine harness that was already attached to the motor but, I've heard that the cobra engine harness does not go with the GT's main wiring.

 

[02silverstang]

Did you use the GT or cobra engine harness?

I just did this swap a few weeks ago and I used the GT harness and everything worked fine, except I had to extend quite a few wires and swap the coolant sensors over. In retrospect, I should have used the cobra engine harness that was already attached to the motor but, I've heard that the cobra engine harness does not go with the GT's main wiring.

+1 ON the harness its good if you used youre gt harness and comp now all you need is someone to tune it . eventhought its a gt comp n harness the engine should still start . check all wiring make sure all grounds are good and that all connection are correct . have done 3 of these swaps the gt stuff will start just not enought to get the proper fuel .

 

[19mustang95]

I did the Identical swap 96gt with 97 Cobra engine. I had no problem with pats or starting. But I used the Cobra Engine Harness and ECM. Plugged the Harness into the firewall plugged ECM in and started right up.
Did you reattach the ground wire that is on the driver side of the block it goes from the chassis to the motor mount?

so the cobra engine harness plug into the main GT harness just fine?

 

[crash549]

i learn something new everyday.

 

[KWClutch]

I'd get the Cobra ECM/Engine Harness and cobra ECM harness. Everything else should work. That'll probably be one of the easier ways to do it.

 

[CleanNGreen96]

Does the car turn on then turn off (blinking Theft light) ? Or does it crank and no spark ? Or when you turn the key does it do nothing at all ? Tell us which one of these youre having trouble with an that will defenitley narrow it down. But I'll tell you that you'll never get it to start with the Cobra ECU, because it will not recognize the GT chipped key unless you bypass it. Like someone said earlier, the PATS.

Don't mean to hijack the thread here, but I'm about 77% through this exact project, and I wanted to know, how many of you guy's re-used your GT computer/wiring and used the 24LB injectors and 80mm MAF ? I was going to just throw the 19LB GT inj and 70mm MAF on their untill I got a tune, but I've heard it will run fine either or. Just wanted to grab a consensus an be safe on this 1...

 

[02silverstang]

so the cobra engine harness plug into the main GT harness just fine?

yes sir might have to extend a few wires but nothing hard at all . then just get a retune and youre set and you can keep your pats ..

 

[02silverstang]

Does the car turn on then turn off (blinking Theft light) ? Or does it crank and no spark ? Or when you turn the key does it do nothing at all ? Tell us which one of these youre having trouble with an that will defenitley narrow it down. But I'll tell you that you'll never get it to start with the Cobra ECU, because it will not recognize the GT chipped key unless you bypass it. Like someone said earlier, the PATS.

Don't mean to hijack the thread here, but I'm about 77% through this exact project, and I wanted to know, how many of you guy's re-used your GT computer/wiring and used the 24LB injectors and 80mm MAF ? I was going to just throw the 19LB GT inj and 70mm MAF on their untill I got a tune, but I've heard it will run fine either or. Just wanted to grab a consensus an be safe on this 1...

this is what i did reused the gt wiring and comp , then i used the cobra maf and injectors the car will start but will run like shit . but after you get a tune the car will run fine . 3 so far no issues , now if you had a 99 n up thats a little more trickey , hope this helps if any of you have questions feel free to call me 210 875-9652 .

 

[OKcobra]

Did you use the GT or cobra engine harness?

I just did this swap a few weeks ago and I used the GT harness and everything worked fine, except I had to extend quite a few wires and swap the coolant sensors over. In retrospect, I should have used the cobra engine harness that was already attached to the motor but, I've heard that the cobra engine harness does not go with the GT's main wiring.

I used to cobra engine harness and just plugged it in right at the firewall on passenger side.

I did the Identical swap 96gt with 97 Cobra engine. I had no problem with pats or starting. But I used the Cobra Engine Harness and ECM. Plugged the Harness into the firewall plugged ECM in and started right up.
Did you reattach the ground wire that is on the driver side of the block it goes from the chassis to the motor mount?

yes i did the ground wire from block to chassis. I did the same thing as you, used to cobra harness and plugged it right in and tried both gt and cobra ECM.

+1 ON the harness its good if you used youre gt harness and comp now all you need is someone to tune it . eventhought its a gt comp n harness the engine should still start . check all wiring make sure all grounds are good and that all connection are correct . have done 3 of these swaps the gt stuff will start just not enought to get the proper fuel .

Would it be easier to pull the dash harness out of the cobra and put it in the gt?

so the cobra engine harness plug into the main GT harness just fine?

Yea man it went right in like the was made for it.

I want to use the cobra ECM because it has been dyno tuned and everything is ready to go. I would rather not have to have it retuned and loose the coin yanno?

 

[OKcobra]

Does the car turn on then turn off (blinking Theft light) ? Or does it crank and no spark ? Or when you turn the key does it do nothing at all ? Tell us which one of these youre having trouble with an that will defenitley narrow it down. But I'll tell you that you'll never get it to start with the Cobra ECU, because it will not recognize the GT chipped key unless you bypass it. Like someone said earlier, the PATS.

Don't mean to hijack the thread here, but I'm about 77% through this exact project, and I wanted to know, how many of you guy's re-used your GT computer/wiring and used the 24LB injectors and 80mm MAF ? I was going to just throw the 19LB GT inj and 70mm MAF on their untill I got a tune, but I've heard it will run fine either or. Just wanted to grab a consensus an be safe on this 1...

When i turn the key, all the accessories come on but the starter won't turn and i cant hear the fuel pump prime.

 

[CleanNGreen96]

Well I've seen 2 of these swaps first hand (Mark VIII) and they went flawlessly both times. But they both retained the GT ECU/harness. My guess is that since you have the Cobra ECU/harness, but are using the GT steering coulumn/cluster set-up, I don't think the proper signals are being read by the computer to fire/ crank the car and prime the pump. And I know for a fact the pin out locations on the GT and Cobra are in-fact different (Referenced Haynes) for that 1.

Here's a link of the exact swap youre attempting pic's and all, and the guy was having the exact same issues as you. Hope his troubleshooting will hepl get youre car up an running ! ! !

[ame=http://forums.corral.net/forums/showthread.php?p=8713886]Cobra Conversion - Corral Forums[/ame]

 

[BraMas]

so the cobra engine harness plug into the main GT harness just fine?

Yup for me it did. I had Zero problems. I get so frustrated on all these Mustang Forums when I see people say use the GT harness and cut wires and extend them or use the GT ECM and have it re tuned. Sure it all works but it is so much easier to just get the Cobra engine harness and ECM and plug and play

 

[CleanNGreen96]

I don't think it's any easier at all, if it was, his car would have cranked up on the first try. An this is just "my educated guess", but I am assuming that since you are using the Cobra ECU/harness, is the reason why youre car is'nt starting. Yeah some say it's plug N play, and those are the very lucky few that managed to work with all 96 stuff "in my opinion". Just because 96-98 are the three years of this sn-95 set-up, 97-98 Ford fooled around with some stuff like the bin files on the ecu, advanced timing and the pin-outs.

Basically when youre turning the key, the wrong signal is being recieved by the Cobra computer through youre "under dash" wiring to the pass. kick panel.
If you feel like reading a wiring diagram and re-wiring all the pin-out's to the proper pin's, that that'll work to. But youre best bet would be to use the GT Comp/wiring. You'd have to delete the IMRC's, and "maybe" extend a plug in or 2, but that would be the sure fire way to get it running.

And if you did manage to re-wire the pin-outs, you's still have to address the PATS issue.... Basically a bigger headache to use the Cobra stuff than to just keep the GT stuff.....

 

[02silverstang]

one more time its much easier to use the cobra engine wiring harness and the gt ecm less problems plus gt comp does not have knock sensors so that means less restrictions , plus like i said you retain youre pats which is a good safety feature if you dont want youre car stolen . just plug n play with the cobra ecm , you will spend more money , reset pats over 150 and you need two sets of keys , plus you will need a tune which range from 400 to 600 . so on the long run with the gt comp youre car will start , plus all you need is a tune trust me i tried all the diferent ways , ecm are not going to give you any hp increase ..

 

[BraMas]

CleanGreen don't take this as me trying to argue! But are you saying I got lucky and just happen to get a Harness and ECM that work with my 96 GT? And that it is a crap shot on doing these swaps weather or not you will get one that is compatible.
And OKCobra did you check that ground? My $ says you forgot to reattach it