4.0 interchange question

[burtgtp1973]

Hi all. nice place you all have here!

I've done some searching and cannot find the answer to my question...

I have a bad 4.0 in a 99' explorer 4x4. I found a pretty good deal on a 4.0 out of a 97' explorer 4x4. I was wondering if it will bolt right up, or if there is other work necessary to make it work?

Thanks in advance!

 

[2000StreetRod]

Which engine?

You failed to mention which 4.0L you have. Your 1999 has a returnless fuel system with the fuel pressure regulator in the fuel tank and a fuel pressure damper on the fuel rail. The 1997 was set up for a return fuel system with a fuel pressure regulator on the fuel rail. You'll have to use your 1999 fuel rail.

If you have an SOHC V6 then the 1997 will have a variable intake system which is not supported in your 1999. It would probably be best to use the 1999 engine wiring harness and upper intake manifold.

 

[burtgtp1973]

yes sorry. I should have clarified. I have the SOHC engine.

"It would probably be best to use the 1999 engine wiring harness and upper intake manifold"

so are you saying the 97' engine will work as long as i use the current (99) wiring harness and upper intake manifold?

 

[2000StreetRod]

fuel rails also

You'll also have to use the 1999 fuel rails. Your PCM is programmed for the higher pressure fuel system.