5.4 Swap - T45 - Ecm?

Space Slug

New Member
Apr 26, 2017
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I've got a 2001 w/ a 3.8l and 4r70w, picked up a 5.4l out of an 03 expedition xlt and a T-45 transmission from craigslist, I need to figure out which ECM will run this setup best.

I've heard that any of the GT ecm's can control the 5.4 w/ 4.6 sensors and a proper tune, but how about the transmission?
 
Your research is correct. HOWEVER the bigger problem is that this project is really a V6 to V8 to conversion.

A 4R70W from a V6 will NOT bolt up to 4.6 or 5.4 modular motor (2 vs 3 bolt starter).

Short answer to your question is that any PCM that is able to run a 4.6 will also run a 5.4. The better question to ask is which PCM would work best in the CAR. Remember that the PCM and the wiring harness have to work together as a TEAM.
 
Your research is correct. HOWEVER the bigger problem is that this project is really a V6 to V8 to conversion.

A 4R70W from a V6 will NOT bolt up to 4.6 or 5.4 modular motor (2 vs 3 bolt starter).

Short answer to your question is that any PCM that is able to run a 4.6 will also run a 5.4. The better question to ask is which PCM would work best in the CAR. Remember that the PCM and the wiring harness have to work together as a TEAM.

The T-45 transmission that I picked up is from a 99 GT, that will be put into the car instead of the 4r70w. I need an ECM that will run the engine and read properly from the new trans. I will be purchasing the wiring harness I need once I know which ECM to put in.
 
I have been wondering about that same question as well .
I think what wmburns is saying basically,simply a computer for a gt should work ?

Yes, any GT ECM will work as long as you install 4.6 sensors and get the ECM tuned.

I was under the impression that the ECM would require output from the transmission and therefore require a certain computer, but from what I have been reading that is not the case. My T45 comes in later this week, I will try to update this thread once the swap is done and everything is running.
 
sounds like a plan good luck I hope all works great ! also food for thought since most is apart and a little more accessible I would think about going ahead and replacing the spark plugs I believe that motor has that two piece plug that could really be a huge pain later on down the road