chazoo1

can someone tell me what exactly what needs to be replaced in a 95 mustang3.8 to a 5.0?

mhefner5

would be cheaper to buy a 95 5.0

Venomantidote95

Engine bay harness and ecm.

chazoo1

I have the enginge harness and ecm, also i changed the dash haeness and the engine compatment fuse harness and now the engine wont start using the key ihave to manually control the starter relay.

chazoo1

Also the horn wont shut off unless i remove the horn relay

Venomantidote95

Sounds like you fudged up greatly! Mine was a 94 v6 and thats all it took, no dash harness just engine bay and ecm.

chazoo1

any suggestions on how to correct my problem and do i have to change the body harness as well?

AdderMk2

undo everything you did... you only needed to swap the engine harness.

Venomantidote95

Adder he has already been behind the dash!
Go back thru and make sure every connector is fully connected!
SN cars arent like foxes, you dont have the hoopla harness issues!
You can go from 5 speed to auto and just swap the ecm!

chazoo1

did I mention that the muatang is a 98, i had a 5.0 sitting in my garage and i was told that all i had to do was chang the engine harness and ecm ,i did that and it wouldnt start so a ford mach told me that becauase of the pats module i need to change the dash harness so i did that, also he said i need to change the engine compartment fuse block and harness so i did that and now my horn works forever i cant start the car withe the key and it does run but it surgee when i hit the gas it trys to reach rpm but struggles and the check engine lite comes on someone please guide me in a better direction.