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Discussion Starter #1
Ok I just have a couple questions here. In order for a 2003-2004 Cobra 4v to be placed into a GT what is needed? Aside from the different intake, 8 bolt flywheel, tuning, etc... Can a GT's electronics work with a 4v? I see numerous complete drive train swaps that include complete motor, trans, wiring harness, ecm, fuel lines, fuel tank, complete vehicle wiring, exhaust, pedals, dash instruments, and so on for about $7 to $10 grand.. Seems nice to have everything included in once purchase, but not sure if it is worth that much. But, if only a Cobra long block is bought, what is the minimal needed to make it work in a GT?

I plan on going 4v in the near future and I am wondering if I should save for a complete drive train swap or piece everything together.... Granted it is always nice to have NEW parts, but if a drive train is in good shape, is it worth it?
 

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Discussion Starter #3
I did read that. But seems the older Marks had a couple different issues with making them work. An 03-04 Cobra motor should be easier...???? Really just wonder if its better to buy new and piece everything together or just buy a complete drivetrain
 

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only real thing you have/need to get is the engine harness, for the extra senors in the termi engine
 

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King Trashmouth
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You can hack together a GT harness to work with a Cobra 4v, but you'd have to be pretty electrically inclined. It's not really worth the effort.

Personally I've got a 01 Cobra harness that has already been modified to work with an 03/04 Cobra setup. See Eaton swaps. You might be able to save a few bucks getting a harness comparable to an 01 Cobra and making some of the modifications, switching coil polarity and different alternator connection are some of the modifications IIRC.

And you should be able to use a GT ECM for it, I certainly plan to. The caveat is that it's certainly getting reflashed before I even turn the key, because the two motors are so drastically different trying to run on a GT tune would be extremely harmful.
 

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Discussion Starter #6
You can hack together a GT harness to work with a Cobra 4v, but you'd have to be pretty electrically inclined. It's not really worth the effort.

Personally I've got a 01 Cobra harness that has already been modified to work with an 03/04 Cobra setup. See Eaton swaps. You might be able to save a few bucks getting a harness comparable to an 01 Cobra and making some of the modifications, switching coil polarity and different alternator connection are some of the modifications IIRC.

And you should be able to use a GT ECM for it, I certainly plan to. The caveat is that it's certainly getting reflashed before I even turn the key, because the two motors are so drastically different trying to run on a GT tune would be extremely harmful.
Hmmmmm.... So getting a complete drivetrain swap would be a smarter investment for a "do-it-yourselfer" and just sell back all the parts I don't use. That way I have all the harnesses and stuff readily available.

I have been following your swap and getting details from it. Keep it up man.
 

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if you are doing an 03 cobra engine, a gt harness or 01 cobra harness wont work. You have a 2nd iat sensor thats wired in and a few others connectors not found in the gt or non s/c cobra harness.
 

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if you are doing an 03 cobra engine, a gt harness or 01 cobra harness wont work. You have a 2nd iat sensor thats wired in and a few others connectors not found in the gt or non s/c cobra harness.
Thank you sir. Now I know what route to take. Reps to you..
 

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You can hack together a GT harness to work with a Cobra 4v, but you'd have to be pretty electrically inclined. It's not really worth the effort.
the only "hacking" for a GT harness to work on a non termi engine is reverse polarity, which isnt hard, because you have to extend the coil pack wires anyways, so just flp them while you extend them. You change the alt connector, you dont cut anything, off, you depin the connector and leave one wire out. You extend one or two other sensors. Its really worth the time and effort since its only 2hrs of work tops to make a GT harness ready for a 4v engine
 
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Discussion Starter #10
the only "hacking" for a GT harness to work on a non termi engine is reverse polarity, which isnt hard, because you have to extend the coil pack wires anyways, so just flp them while you extend them. You change the alt connector, you dont cut anything, off, you depin the connector and leave one wire out. You extend one or two other sensors. Its really worth the time and effort since its only 2hrs of work tops to make a GT harness ready for a 4v engine
Definitely worth it. The 4v has so much more potential and the power and torque comes so much easier.. Just started a build sheet and doing the usual stay 2v or go 4v debate. I am sure with all of the intelligent and mechanically inclined people on here, I shouldn't have a issue finding answers to most problems. Even a ****tard like me should be able to build a car.:eek:
 

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the second iat senser is also a map senser. if using a gt harness i would use the iat lines off the maf and tap the intake with a lightning iat2 senser since it is threaded and strictly a iat senser.
 

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King Trashmouth
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if you are doing an 03 cobra engine, a gt harness or 01 cobra harness wont work. You have a 2nd iat sensor thats wired in and a few others connectors not found in the gt or non s/c cobra harness.
:dunno

It's been done before, all the Eaton swap guys do it.
This is what I was referring to when I said lots of work, if you want to do it exactly like the 03/04 you'll have to tap directly into the OEM connector and add some of these to the harness.
Of course you can do the easy route and omit sensors, or bridge them.

I was originally going to just reuse the Eaton swap harness I had, but I may end up just getting an 03/04 harness. This would make my ECM programming dramatically easier.

Back to the whole "doing things right" biting me in the ass again. Looks like combining an Eaton swap with an 03 Cobra engine might be a bit more complex than anticipated.

Does anyone have the OEM wiring diagrams for the 03/04, 99/01, and GT? That might help to see exactly what you can achieve.

EDIT:
Here's what little I've found so far. Going to look them over later. Hopefully someone has better diagrams than I've found.
2003 Cobra (unfortunately none of the sensors we're interested in):

2003 Cobra pinout courtesy of SVTP:


2001 Cobra pinout:

2000 GT pinout (some of it):


I'll have to sort them out later.
 

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Discussion Starter #13
HOLY CRAP!!!! Those will definitely help with a complete wiring from a cobra. Should be tons of fun........
 

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Hey can u fully explain to me how to do it I have a 01 gt and got a 99 cobra motor I have my gt harness wire out but I just wanna make sure that I'm cutting and extening the right wires and how to reverse them plus the alternator wire setup
 

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King Trashmouth
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Holy blast from the past, batman!

I think there's some much better write-ups out there. I ended up using my GT harness. Coils are the biggest part. Swap the polarity by popping out the key, pushing the terminals out the back of the connector, and swapping them around. Ensure that the fat red or WH/BL wire goes to the "B+" on the 4V coil. Next separate out the positive wire (red or WH/BL depending on year/model) from each bank. Extend that so that it reaches the front coil on the 4V, running through the valve cover like they do. Branch off of that for each coil and splice to the connectors. Then you just need to extend each individual driver wire from where it was before to where the coil is now.

As for extending things that will depend on engine. For an 03 Cobra I had to extend TPS, IAC, ECT, and alternator. You may or may not need to change the alternator plug. I did not.

I recommend searching for better write-ups on this. They're out there.
 
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