Your opinions on FI

OK,

I have an idea to try and retrofit a YJ fuel injection to my 258 I6. what I am meaning is the central fuel unit and fabbing an adapter to get it to mount on the intake manifold.

am I nuts or does this sound plausible.

I already have all the stuff here its just do I try it and didnt know if it may have ever been tried before.thx

 

You mean the Mopar MPI? It's been done many times, but if the donor is a 4.0L, a head swap is the best route. The 4.0L HO head flows much better than the 258 head.

If this is TBI from a 2.5L, I expect the throttle body will be too small. You'd be better off scrounging the parts from a GM 4.3L and burning your own PROM (or flash memory).

 

Yes the donor is the 2.5 4, I was thinking along the lines that the 4cyls MPI would be less cfm equaling to that of a small jetted carb giving better overall MPG. Im not worried about HP on this one, just a better fuel economy and trail use without bogging due to angle tilt problems that plague the carbs. I should be able to modify an adapter out of another adpter I have, it fits the manifold I currently have and the holes are off only slight, I have access to a mill that I can use to fix that.

I just thought since I had it all in hand I know I can get it on there, its just a wonder if anyone has done a swap. I need to know what all I need. I know from past experience all I needed to FI my Mustang was a FI harness that attached the unit up to the computer, and the fuel pump to drive the injectors. Im just wondering if I can graft out the harness for the FI out of the rest of the 89s harness w/o having to use the whole thing. and in the end is it worth it.

 

I don't think the 2.5L FI will work very well on a 4.2L motor, just not enough fuel. Also I don't know if the 4cyl FI system will work on a 6cyl motor.

 

:iagree:

If you do decide to do it and it works, let us know what all is involved in the swap. I don't have any experience in this particular swap but I know that if you can go to FI it is definately worth the effort.