I have swaped out my engine with another from a 2005 that has less than 4k on it. Now that its all installed and running I have a problem. Although it starts and idles perfectly when i press on the gas it first hesitates but after a second or so it revs up nicely. Also when I do this it seems as if its about to stall also. So my question is what could I have overlooked that could have cause this problem?

On another thought I did notice when I installed the engine a difference in the two the 02 engine had a fuel rail with a return but the 05 didnt, so I swaped the two, although having alittle trouble lining up the injectors. So Im not sure if this could have caused a problem or not, I thought Id mention it anyway.

 

from what I think I know the fuel systems on the two engines are different. The 05 engine has a returnless fuel sysem I do believe. Somone can clarify this. But the fuel system is different. Theres a company now, A2 designs I do believe, that sells a kit to convert it.

 

Yes, the 04-05 have a returnless fuel system. the 02-03 model DOES NOT....unless you have an ECU from an 05 in the car i would have expected to encounter some sort of problems in the fuel system. like MITSUOZBOI said A2 Designs sells a kit to convert the 04-05 to a system with a return line.

 

Comatose got there, When doing engine swaps ecu needs to be replaced with engine. The data stream to the computer is confused. Talk to your mechanic, and have him check values on sensors signals to ecu. If he is a member of IATN. they may have known good values

 

don't bother talking to a mechanic. if you swapped the full engine out of an 05 you already know the problem. either get an ECU from www.car-part.com or convert it over to have a return line.

 

Finally I have it right! I talked to mitsu mechanic and he told me that after doing the same to a customers car they had to swap everything other than the head and block in order to get it to run correctly. I did that and viola no more hesitation.

 

Not sure what exactly but there must be a difference between the intake manifold from the older models compared to the new. So if anyone is looking or have to do the same as I did just make sure you do that part first so you dont have to go through the trouble I did having to swap manifolds while the engine is in the car.

 

By the way does anyone know what the difference is? Visually they look exactly the same.