98 4.6 in a 99, what will i need?

kovacs22 · Feb 23, 2004

soo...

Are you saying i should buy a 99+PCM, harness, fuel rail, and 8 coil pack+wiring for my 98 4.6 to be installe din my 99?

bdcardinal · Feb 23, 2004

basically ya. also, is the radiator in a v6 the same as a gt?

kovacs22 · Feb 23, 2004

Yeah im 99% sure that the radiators are the same, the difference is in the module for the electric fan. I may be wrong but i think thats what it is,

kovacs22 · Feb 23, 2004

Oh yeah and could someone please give me alist of vital things (PCM,harness,rails ETC) that i am going to need for the installation?

Thanx,
ryan

Sam98 · Feb 23, 2004

kovacs22 said:
Are you saying i should buy a 99+PCM, harness, fuel rail, and 8 coil pack+wiring for my 98 4.6 to be installe din my 99?

Yes, that is exactly what I'm saying. There were a lot of changes between 98 and 99.

You will need everything you mentioned but everything else from the 98 should work for you. You could use the 98 PCM and wiring, but you would have to use the instrument cluster from a 98 and the wiring harness from the transmission, and you would also have to replace the fuel system. Also the parts you listed can come from any 99-04 GT even though there have been minor changes since 99. If you use the PCM from an 02-04 GT, you will also have to replace the fuel injectors.

kovacs22 · Feb 23, 2004

Is this what i need?

-Engine harness from 1999 4.6l 2v crate motor. Harness part # on tape band...xR33 12B637 B129K AL.

kovacs22 · Feb 23, 2004

or this

- Speed density 1988 Mustang GT. It is a 5-speed computer. The numbers are EEC-IV SFI-SD1 E7SF-12A650-A1B.

kovacs22 · Feb 24, 2004

Anybody know??

rayray50dawson · Aug 20, 2015

I am doing the opposite. Im installing a 98 engine into a 99 gt. Motor already set down in. Do I need to change the motor harness and coils to work on my car?

wmburns · Aug 20, 2015

IMO this could end up being a train wreck. Some of it from poor planing. Some from bad advice.

From looking over this thread it's clear there's a misunderstanding about what should kept and what to swap when performing a motor swap.

IF putting a 98 V8 into a 99 GT, this is a straight forward swap. It's a silly swap but it will work without a ton of re-working as it's basically a Windsor to Romeo swap.

Why is this a silly swap? Because it's very easy to find low mileage PI Romeo's from wrecked 2001+ Town Car, Grand Marquis, Crown Vic. I paid $800 for a 35k mile 4.6 from a 2003 Grand Marquis. It doesn't seem to me that $500 for a motor that really isn't a good fit is a "steal".

IF putting a 98 V8 into a 99 V6 car, this is anything but a straight forward swap. All I can say is, bumpy road ahead. Good luck.

For everything that follows I'm going to assume that the swap is a 98 V8 into a 99 GT:

In a modern car, the electronics are king. If you are looking for a straight forward swap, the goal should be to retain as much of the original car's external systems as possible.

The talk about needing to change the fuel system is wrong. The fuel system is basically an external support system to the motor. That includes the wiring, induction, exhaust.

Note, I have done a Windsor to Romeo motor swap. So I'm speaking from direct experience. What I did was put both motors on engine stands and make the new motor look like the old. When this is done there are only minor differences between the motors which are solvable (PVC, heater hose, temperature sensors, flywheel, front belt routing, ignition, ect). There are tons of threads on how to do a Windsor to Romeo swap.

Should this really be a V6 to V8 swap, there are tons of threads on this swap as well. These are not as likely to be encouraging. Should this be the case, allow me to apologize for adding un-needed information to your thread.

rayray50dawson · Aug 20, 2015

wmburns said:
IMO this could end up being a train wreck. Some of it from poor planing. Some from bad advice.

From looking over this thread it's clear there's a misunderstanding about what should kept and what to swap when performing a motor swap.

IF putting a 98 V8 into a 99 GT, this is a straight forward swap. It's a silly swap but it will work without a ton of re-working as it's basically a Windsor to Romeo swap.

Why is this a silly swap? Because it's very easy to find low mileage PI Romeo's from wrecked 2001+ Town Car, Grand Marquis, Crown Vic. I paid $800 for a 35k mile 4.6 from a 2003 Grand Marquis. It doesn't seem to me that $500 for a motor that really isn't a good fit is a "steal".

IF putting a 98 V8 into a 99 V6 car, this is anything but a straight forward swap. All I can say is, bumpy road ahead. Good luck.

For everything that follows I'm going to assume that the swap is a 98 V8 into a 99 GT:

In a modern car, the electronics are king. If you are looking for a straight forward swap, the goal should be to retain as much of the original car's external systems as possible.

The talk about needing to change the fuel system is wrong. The fuel system is basically an external support system to the motor. That includes the wiring, induction, exhaust.

Note, I have done a Windsor to Romeo motor swap. So I'm speaking from direct experience. What I did was put both motors on engine stands and make the new motor look like the old. When this is done there are only minor differences between the motors which are solvable (PVC, heater hose, temperature sensors, flywheel, front belt routing, ignition, ect). There are tons of threads on how to do a Windsor to Romeo swap.

Should this really be a V6 to V8 swap, there are tons of threads on this swap as well. These are not as likely to be encouraging. Should this be the case, allow me to apologize for adding un-needed information to your thread.

my problem is the fact that I purchased this vehicle without an engine or engine harness. I traded for an engine with harness from a 98 gt. Both gt cars I should add.... I have the engine bolted and mounted in place. I put a fuel rail on the 98 engine that works for 99 with rhe non return system... and I now have a sensor on fuel rail that I disnt have previosly on the engi e. Also still has 99 ecm... what

wmburns · Aug 20, 2015

If you use an engine wiring harness from a 98 GT in a 99 GT you should EXPECT problems. Why? Because the 98 and older used a coil pack ignition system where as the 99+ uses COP ignition. The wiring is different. As such, the PCM will not know how to communicate.

Also EXPECT that the motor will not start unless the fuel rail pressure sensor is connected. Also expect problems unless the return-less style fuel system is used.

rayray50dawson · Aug 20, 2015

I did swap the returnless fuel rail onto it. I found one at a buddies house. I suppose I just need to located a wiring harness off of a 99-04 to run my engine. I got coilpacks already. And the fuel rails.

98 4.6 in a 99, what will i need?

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