03/04 engine/trans swap into 01

[Slowings]

Hello.

I recently purchased a refreshed engine and transmission locally from an 03/04 cobra. I have the following parts aside from those:

Heat exchanger and bracket
Intercooler hardliners
Aftermarket IC pump
03/04 engine harness
I also have an 03/04 tank and pumps.

I have a couple questions, but they aren’t all related, so going to number them, and spares me needing to make any other posts about the same thing.

1: I’ve heard if I don’t have an 03/04 cluster ecu pcm etc, it is more than possible to retain all my stock 01 wiring/cluster. I am running into the hiccup where I have both the 03/04 and 01 harness next to each other and I am trying to realize what the differences are, but I don’t have a wiring diagram to see exactly what sensors are what, and what will need extending/what I can go without. Has anyone here done the swap and kept their 01 harness that would allow me to pick their brain? It would be really cool if I could just talk to someone that’s got the experience in this since I got this far without doing the cluster/ecu/pcm swap I don’t want to get into that now.

2: I have the whole nest of vacuum lines for the 03/04 but I don’t have the slightest clue of where they are supposed to be routed, I imagine there’s got to be a thread for this but I cannot for the life of me find it. I’ve searched svtp and Facebook groups. Does anyone have this book marked or something that can share the link with me.

3: is the 03/04 tank necessary? I have been doing this swap in my spare time for months, and I am burning summer away, I want to get the car running and experience it before this winter, so if I can keep with my stock 01 tank that would be perfect, but I’m unsure if I am able to with the fuel that the new engine will be needing. It may sound dumb but I am trying to get this thing done asap so I can get a tune and enjoy it for a few months, and plan on rebuilding my IRS this winter, so if I can get away with my stock tank, and just do the swap when I get my irs done that’s really what I want to do, I’m just sick of working on this car right now and need the slightest bit of satisfaction before I lose interest in completing it. This is the biggest project I’ve ever taken on and im learning as I go so hopefully that can be understood haha. I thought physically putting the engine and trans in would be the hardest part but man this is killing me!

4. Is there any parts it sounds like I’m missing? Like I said, I’ve got the engine, trans, their harnesses, the hard lines, pump, bracket, ic tank, throttle cable, driveshaft is all in as well. I know for sure I’ll need the soft hoses associated with the cooling system, but I really don’t think I need anything else. Are the PS lines necessary? I went ahead and got the line that goes over the PS tank, will I need anymore?

Thank you for any help I can get! I just want to get this done, taking up all my garage space and I won a 13 GT in a raffle this year so the more I’m driving that the more I’m loving it, and one of these damn cars is getting sold, I need to drive my old baby again to see if she’s stayin or goin

 

[LS WUT]

I want to say I have something saved for sure in my archives for this swap. My buddy did it to his 99 cobra. I’ll see if he has it, or if I can find it on my laptop.

Secondly what the ****? How did you win that bad ass car in a raffle hah?

 

[P49Y-CY]

i know that the fuel pump wiring in the body harness is different, like the way the inertia switch is wired into it is sort of backwards backwards compared to non 03/04 cobras

 

[01yellercobra]

Use the 01 harness. No need to run the 03/04 harness. You'll just have to move/extend some wires for the IAT, IAC, and alternator. Run the intercooler pump off a relay.

The tank and pumps are plug and play. The wire colors are different, but everything works just fine. I would suggest doing a wire upgrade while you're there.

 

[01vert]

You have all the front accessories from the 03 motor? Alt and bracket, water pump, pulley bridge etc?
you could run the same tank but if you leave a stock 01 pump in it expect the motor to last about 4 seconds under full throttle. If you have the 03 fuel hat with dual pumps you have to tear the internal basket out of the 01 tank and use that. Don’t go below half a tank or you risk fuel slosh and lean starvation.

IAT needs to be post blower not before. Make sure that’s wired properly. Suggestions above mine all make sense.

 

[01vert]

Forgot to mention start looking through old posts here about the swap and the mach 1 forum had a ton of posts on it too iirc.

 

[Slowings]

I want to say I have something saved for sure in my archives for this swap. My buddy did it to his 99 cobra. I’ll see if he has it, or if I can find it on my laptop.

Secondly what the ****? How did you win that bad ass car in a raffle hah?

thank you! And yeah luck was on my side, 6 draws, I won the first 3, the car, $500 and $250. Collectively spent around $300, however, $15 is what I spent total on the 3 winning numbers basically engine is stock, 92k miles, boss Intake manifold, headers. But has a t56 magnum swap and air ride suspension.

But man there’s nothing I want more than for this car to get done. Just this harness situation and the trunk have me stuck I just want to hear this whine and see if it’s all I wanted it to be

 

[Slowings]

You have all the front accessories from the 03 motor? Alt and bracket, water pump, pulley bridge etc?
you could run the same tank but if you leave a stock 01 pump in it expect the motor to last about 4 seconds under full throttle. If you have the 03 fuel hat with dual pumps you have to tear the internal basket out of the 01 tank and use that. Don’t go below half a tank or you risk fuel slosh and lean starvation.

IAT needs to be post blower not before. Make sure that’s wired properly. Suggestions above mine all make sense.

Yeah it was a complete swap. But **** thanks for telling me about the tank. I guess I’ll get to work throwing that in. I need to figure out the sensors and what not because that’s what has me messed up. I don’t know exactly what each sensor is, especially now because I sold my 01 engine so I’m drawing blanks as to what each sensor is.

 

[Slowings]

Use the 01 harness. No need to run the 03/04 harness. You'll just have to move/extend some wires for the IAT, IAC, and alternator. Run the intercooler pump off a relay.

The tank and pumps are plug and play. The wire colors are different, but everything works just fine. I would suggest doing a wire upgrade while you're there.

Again probably going to sound dumb but I really just looking at these harnesses I don’t quite know what the iat, iac sensors are. I also have the starter relay harness from the 03/04 I was going to use as ppposed to the 01 since that had some sensors on it that didn’t align. Initially tried to just use the 01 and had it on there before realizing it wasn’t a direct swap for that. So was hoping to use the 01 top engine harness, and 03/04 starter/alternator harness.

 

[01yellercobra]

The harnesses are different enough that you can't do what you're wanting to do.

IAT=inlet air temp. The 03/04 has a sensor for that on the lower manifold. You want to tap into that one. The 01 sensor is in the intake pipe by the MAF. So you'll need to extend the wires.

IAC= idle air control. Silver canister by the throttle body.

I'm sure you can see the issue with the alternator wiring.

 

[Roush6018]

Hey Man, this engine swap you are attempting is no joke. I have a 03 cobra swap in a 01 mustang and its so crazy how much needed to be changed. i have a stock pulley due to smog but the supercharger does still whine pretty good. my car is pretty fast too.

the thing i have to add is i noticed you want to get this car done and on the road, fast! that is where this does relate to money. and it is the result of how many hours you spend tying to figure this thing out, wasted due to no progress. but it would cost so much money to have a shop tackle the job, and have it done faster.

the thing that hurts is when you get the swap started and running and then things like the alternator, the clutch, and the rear diff start to wear out and cost you more than the car is worth. the reason you say you want to choose between the blue GT and your baby is because you have so much time and money in that car and you should enjoy it for a long time. the blue GT can be replaced.

i did get my swap started up and driving with a GT tank with the baffles removed and the dual 03 cobra pump assembly dropped right in there!!! then i spent the hundreds of dollars to install that 03 cobra tank myself. <-some expensive baffles there but they did make me feel the swap was done right.

 

[hotcobra03]

Home

Terminator Cobra Home

www.terminator-cobra.com

Link for manual, wiring diagrams. And other good stuff

03/04 Cobra Vacuum Lines Documented

I have been apalled by the lack of documentation regarding the vacuum and boost lines for the 03/04 Cobra. I am collecting parts for a Teksid Terminator motor I am slowly building for my 96 Cobra, so I have most of the lines and parts in my collection. A friend asked me to help with getting his...

www.svtperformance.com

Link for vacuum hose harness

 

[kezell]

It’s definitely worth it.

 

[Slowings]

It’s definitely worth it.

Did you do the swap yourself? If so plz pm me haha

 

[RX1Cobra]

If you haven't already pulled the stock 01 harness I'd just use that. I eaton swapped mine and followed this write up. It's been 10 years so its kinda hazy.

But the main differences were i think you need to flip the two wires for the alternator and our iat is the tube not in MAF (compared to the Mach in the write up). I put my IAT post blower.

I also have the 03 tank/pumps in my car and it was plug and play. Tuner had no issue tuning the car with 01 harness and computer. Haven't had to do anything to it in the last 10 years. Cars runs great still.

Eaton Swap....Part II - 2003-04 Mach 1 Registry Owners Club

Eaton Swap....Part II Power Adders

www.mach1registry.org

 

[kezell]

Did you do the swap yourself? If so plz pm me haha

I did do it myself. However I swapped all wiring etc. Only original wiring left was the door harnesses.

 

[Roush6018]

i did my cobra swap myself, i changed the; power distribution harness to cobra, ecm harness to cobra, changed ecm to cobra and eventually changed the dash harness so my 03 cluster would read the boost. i just added the wire necessary to my body harness that runs from passenger footwell to the FPDM in the trunk.

i do have a bad experience with this swap because back in the day smog was easy to pass. i had a 2.93 RR upper pulley and i liked that size upper pulley the best. then i got a 2.76 pulley with catted mid pipe and put down 460hp to the tires.

then i had to smog my car recently and they sent me to the Referee. i changed my upper pulley back to stock and i have the factory mid-pipe. only mods i have now are K&N intake kit and a SLP LM1 catback and JBA shorty headers and ported blower. my car is still VERY fun to drive, however i am upset i had to take the mods off my car.

 

[Slowings]

If you haven't already pulled the stock 01 harness I'd just use that. I eaton swapped mine and followed this write up. It's been 10 years so its kinda hazy.

But the main differences were i think you need to flip the two wires for the alternator and our iat is the tube not in MAF (compared to the Mach in the write up). I put my IAT post blower.

I also have the 03 tank/pumps in my car and it was plug and play. Tuner had no issue tuning the car with 01 harness and computer. Haven't had to do anything to it in the last 10 years. Cars runs great still.

Eaton Swap....Part II - 2003-04 Mach 1 Registry Owners Club

Eaton Swap....Part II Power Adders

www.mach1registry.org

You didn’t have to run a secondary wire back to front for the 2nd fuel pump? I thought I saw in a post that a wire had to be ran. If it’s just plug and play and done I will get this done today haha.

 

[RX1Cobra]

You didn’t have to run a secondary wire back to front for the 2nd fuel pump? I thought I saw in a post that a wire had to be ran. If it’s just plug and play and done I will get this done today haha.

Nope, plug and play. I have the stock 03 MAF, injectors, pulley and pumps. Makes 440 whp with no fueling/tuning issues at all on the stock 01 computer.

 

[Slowings]

sweet. So sounds like my only hold up is in fact the modifying of this 01 harness.