BAttitude7689

I'm planning on doing a motor swap, i currently have a 98' GT NPI motor and I'm swapping a 03" PI motor in the car, i know the motor plug and plays and fits right in with really no issues but my brother brought up a concern to my attention today about the swap and i wasn't sure about. As for the fuel system I've been told my 1998 4.6 motor has a return line from the gas tank to the motor and thru fuel rails. but on the 03' 4.6 i was told they went to a return-less fuel line for the fuel to cycle?? Im not really sure if that's accurate or not but would like some more insight on the situation. as for that is there any other factors i should have to worry about with swapping the 98' motor with the 03' motor? thank everyone for the help

0949er

I guess to build off your other thread, what all ARE you getting with the motor? are we talking ALL necessary hardware? Intake, MAF, Throttle body, heads, etc, all that good stuff? or JUST the motor (or block)?

BAttitude7689

its a fully complete motor

nascrchi

I just got done doing my motor swap: 96gt with NPI to a 96gt with 04PI motor.

My advice to you: I'm not sure if you're in a tight budget, but if you can, go with a cobra motor. I didn't quite feel a diff from the 96gt to the 04 gt maybe because I simply want more. Alittle more pull and TQ, and better sound, but nothing much. I was on a tight budget and went for it because the motor only had 25k miles from a 2004 gt.

But on the flip side, you will need to change the oil pan from the 96 motor the 03 motor so the sensor from the 96 gt fits and the gauge is functioning.[i didnt ].

Another thing, the 03 gt motor has two sensors- one for the temp gauge AND one for the fan. the 96 gt doesn't; the 96 motor has only one plug for both sensors. The solution to this to me is unknown to me. I just have the fan running all the time. I truly don't know if thats a bad thing but idk what to do other than to buy a switch and do it manualy.

hope this helped.

BAttitude7689

hey thanks man for the help....i will keep that in mind when i do the swap but did you have any issue with the fuel lines?? and did you use your same wire harness or did you use the harness from the 04 motor?

nascrchi

you will need to use the harness from the NPI motor as well as your alternator. The COP's will not work for you as you will need to use the distributors from your NPI motor. Also, you will need to change the throttle bodies because one has an extra insert in which the NPI has and 03 doesn't. Other than that, I suggets you get yourself a clutch. Get the clutch for the t-45, which I assume you have, and of course resurface the flywheel.
I went ahead and bought an OEM clutch fork as well so my shifts were smoother, not quite needed. As of now I think thats it.

hotroded

hey man what was the final outcome of your engine swap and what happen with the fuel rail set up what did you end up doing ?
i'm am in the middle of doing the same swap and have dead ended rite now
just waiting on some answers ?
also my injector plugs are different did you have the same plugs on your motor ? did you have to change the plugs on the injectors?
anybody with any information on this swap i would really apreciate it
thanks for your help.

BAttitude7689

well as for the fuel rails , i used my stock 98' fuel rails and actually my entire 98' fuel system,i belive i used the same injectors as well, and used my same alternator as well because the voltages were different i believe

hotroded

thanks man thats what i heard and will be doing switching to my 96 fuel system what about your throttle body,did you have to change the throttle body to your original body also?
did you have any problems with tuning it because the intake ports are alot bigger on the pI motor ?

BAttitude7689

well i had already changed my throttle body and plenum to an aftermarket i belive it was BBK TB , as for tuning it, i got rid of my diablo sport tuner and decided to get a sniper tuning and the car run just fine, but remeber with my swap i did an 03 motor & 03 (auto) tranny, i ran into problems which the fact the VSS and the OSS were slighting different because I was running an automatic , there would less issues with a 5 speed but if your running an auto, I will go into what I had to do to get the car to run and drive correctly