98 to 03 Cobra...project
- Thread starter KWClutch
- Start date
Dumb question I know, but I've always wondered... What exactly do you need to use an 03-04 cluster?
This is mostly a guess but I'm pretty sure you would need a matching computer and harness and you'll have to turn off PATS in the tune. I can't remember if the 03 PCM harness will mate up to the 96-98 dash harness, so you might end up having to do some sort of wiring conversion.
If I remember right the PCM harness attached inside the passenger fender or maybe way far up under the dash but I don't think you have to remove it.
Get confirmation from someone else before you pull it. I could be wrong. Seems like I remember unhooking it without pulling anything. I did have the fender liner out.
I kept my 98 computer and converted to COP. Have your tuner change the dwell cycle to what a COP car would use. The wiring is a lot of wires but not too difficult. Unwrap the coil pack wires from the engine harness and start labeling things.
I ended up unwrapping the tape and putting wire loom on them and then taping the wire loom. I didn't grab any photos but it looked much better.
Here's the wiring which I got from tccoa.com:
https://docs.google.com/Doc?id=dgcxhnzw_12c5z2qfhp&hl=en
Ok, so to clarify, it looks as though the original coil packs plugs have 5 wires? One hot and one signal wire per cylinder?
Any chance you could supply a bit more detail?
Josh, I did the swap on my 99 gt. Obviously there were major changes between your car and my 99 but I'll try to give what info I can.
I see you've decided to go with the 03 ecm. I believe there will be an issue if you use the 98 cluster and dash harness. The 98 is analog and the 03 is digital. You would have to swap out to an 03 cluster and dash harness or get a 99 gt's harness and cluster and I can walk you through the wiring mods that you would encounter - there a several. I would try to get a complete 03 setup if I were to do it again. It sucks pulling the dash but if you do you can replace your heater core while you're in there. And if you replace the HC then see if you can use the newer style that have the quick disconnects. They make it a lot easier to get the hoses on and off when installing and removing the motor.
Using the 03 ecm, ecm harness, and engine harness has a big benefit of being able to see Inlet Air Temp 1 AND Inlet Air Temp 2 (post blower). If you use the 98 engine harness, then you can only send one of these signals to the ecm. Obviously you would want to see IAT2's more than IAT1's and in order to do this you would have to extend the IAT1 wiring.
As for the fuel scenario. Return is the way to go if you're making big power (500 rwhp and up in my opion). If you go return you could use the 98 tank and hat but you would be close to maxing out the single pump. That single 255 lph pump will handle 400-500 hp. A BAP is an option but IMO that would stress the pump by spinning it harder than it might be designed to handle over a long period of time. When it starts giving out you run lean and then it's bye bye motor on a WOT run.
If you use the 03 ecm and all the harnesses ,including the body harnesses, then you should use the 03 tank and stick with the returnless setup (until you get crazy with the power level). Upgrade the pumps to GT supercar pumps, and add a second Fuel Pump Driver Module (and custom harness or the Lethal Performance harness) to handle the extra heat that those pumps will create in the FPDM or get a Zone 5 Mega Driver (I don't think you need the harness for this route but I'm not 100% sure).
I may have created more questions in your head than answers with this reply, lol. Sorry if I did.
Good luck with it and I'll keep an eye on this thread if you have any questions.
Oh, and one thing I just thought of. With the t56 reverse lockout you need to run a switched power source to it off of your brake pedal switch if you don't use the Cobra engine harness. Just one more thing to consider... it's maddening sometimes weighing all the options! GL!
I see you've decided to go with the 03 ecm. I believe there will be an issue if you use the 98 cluster and dash harness. The 98 is analog and the 03 is digital. You would have to swap out to an 03 cluster and dash harness or get a 99 gt's harness and cluster and I can walk you through the wiring mods that you would encounter - there a several. I would try to get a complete 03 setup if I were to do it again. It sucks pulling the dash but if you do you can replace your heater core while you're in there. And if you replace the HC then see if you can use the newer style that have the quick disconnects. They make it a lot easier to get the hoses on and off when installing and removing the motor.
Using the 03 ecm, ecm harness, and engine harness has a big benefit of being able to see Inlet Air Temp 1 AND Inlet Air Temp 2 (post blower). If you use the 98 engine harness, then you can only send one of these signals to the ecm. Obviously you would want to see IAT2's more than IAT1's and in order to do this you would have to extend the IAT1 wiring.
As for the fuel scenario. Return is the way to go if you're making big power (500 rwhp and up in my opion). If you go return you could use the 98 tank and hat but you would be close to maxing out the single pump. That single 255 lph pump will handle 400-500 hp. A BAP is an option but IMO that would stress the pump by spinning it harder than it might be designed to handle over a long period of time. When it starts giving out you run lean and then it's bye bye motor on a WOT run.
If you use the 03 ecm and all the harnesses ,including the body harnesses, then you should use the 03 tank and stick with the returnless setup (until you get crazy with the power level). Upgrade the pumps to GT supercar pumps, and add a second Fuel Pump Driver Module (and custom harness or the Lethal Performance harness) to handle the extra heat that those pumps will create in the FPDM or get a Zone 5 Mega Driver (I don't think you need the harness for this route but I'm not 100% sure).
I may have created more questions in your head than answers with this reply, lol. Sorry if I did.
Good luck with it and I'll keep an eye on this thread if you have any questions.
Oh, and one thing I just thought of. With the t56 reverse lockout you need to run a switched power source to it off of your brake pedal switch if you don't use the Cobra engine harness. Just one more thing to consider... it's maddening sometimes weighing all the options! GL!
Each coil pack connector has two trigger wires and a 12V for a total of 6 wires across the two. The 12V from each side can be treated the same. So i spliced half the wires into one 12V and the other half into the other.
Anyone know where I can get the male side of the coil pack connectors in pigtail form? If I could find them I would build harnesses for people wanting to do this swap without cutting wires. Normally the coil pack is the male side.
For fuel, you might want to check out this tank setup a local St. Louis guy has up for sale:
Sumped Stock Gas Tank For 99 Up - STLMustangs Forums
Sumped Stock Gas Tank For 99 Up - STLMustangs Forums
Ok so here is the plan so far. I'm going to use the 03 ecm/engine harnes/pcm harness and splice the 98 interior harness into the 03 pcm harness. I've heard this can be done pretty simply. I'm not sure if my cluster is going to fuction 100percent right so I'll try it and see. I can always get a 99-up cluster if I need to but the other interior stuff should work. I'm going to keep returnless until I get past the 500 hp range then modify the 03 tank to return style and use a aeromotive regulater to send fuel back. I should have the transmission today and hopefully will have the motor and trans in the car by tonight.
Do the head cooling mod while the motor is out.
It's a religious debate on here as to whether or not it's necessary but with the motor out of the car I would absolutely do it. You're going to be getting on that car and anything that helps prevent the pistons from melting is a bonus. 
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