I have seen some posts people putting dodge neon injectors in their xjs anyone heard of this what do you gain by swapping them ?????

 

There are about 1000 threads on this issue. The search function is your friend.

The short version, stock injectors have 1 hole, the neon's have 4 for better atomization of the fuel. Typically results in better throttle response and smoother idle. Some report better mileage, others not so much.

It's a very easy swap to do.

 

I got some good gains ~2 mpg more by doing the swap and a smoother idle. I'd recommend it.

 

Is it a straight swap or is there any modifications that need to be done what year neon injectors fit a 1991 xj 4.0?

 

early 90s i belive, you want the "703" injectors, you can tget them out of other chrysler models too

 

Yeah look for any older neon, stratus, cirrus, caravan. They are all over the junkyard and it's a direct swap. You can find 6 703 injectors in 30 minutes I bet.

 

Depends on the year, which was finally posted by the OP.

 

That also depends on the location and junkyard. I had to visit two different yards in my area to acquire a full set.

I don't think I got any mileage gains but I haven't calculated it to find out. I did get a smoother idle, faster startup, and slightly quicker acceleration.

 

Very typical results.

 

I have the MPG overhead unit and it went from ~10mpg to ~12mpg so I can't complain.

 

I love my neon injectors with the bored T/B, 99 manifold, 1"spacer, jeeps low end is alot better.

 

^What MM is your TB? I was thinking about upgrading myself.

 

Renix can be bored to 60mm, HO to 62 IIRC.

 

Once the Injectors are installed, is there any process that needs to be done for them to work properly. like a calibration or system setup?

 

Nope, just plug 'em in and go.