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fuel injector replacement

Dan1990XJ

NAXJA Forum User
(90' XJ 4.0 AW4 122,000mi.) fuel injectors are starting to go bad and was wondering how hard are they to change, if its not that hard i would like to do it myself instead of paying someone else to do it.
 
I'm surprised about the injectors going bad. Personally, before I shelled out the $$$ for new ones, I would run a can of BG44K through your gas. Not the cheap STP type crap. BG44K is simply amazing, and yes it runs about $18 a can. I run a can every 1oK miles on every vehicle I own. It also takes the carbon out of the cylinders. I used to have a bore scope and I did a before and after check. It was spooky.
 
Its really not that bad. You need to disconnect the fuel rail (4 bolts), disconnect the electrical connections (label and remeber where each goes), pull out the old injectors, install new ones. I have done it without disconnecting the fuel lines, but if the seals have never been changed, you might want to change all of them while you are at it. The injectors will come with their own o-rings, but you will need to go and buy some for the fuel lines. I think Chrysler sells a kit, but I just went to Autozone and found some the were identical. There are 2 o-rings with a small spacer in between them for each fuel line connection. Keep that spacer if you plan to go and find your own o-rings like I did. If you are getting the kit, it should come with them along with a tool to install them. I did mine the hard way before I knew about the kit. I recommend the kit. If you havent bought the injectors yet, I would look into www.fiveomotorsports.com for the injectors. Your jeep will need 19lb injectors and they are real cheap from FORD. They sell them in a set of 6 or 8. I also did not know about this and spent arounf $300 for mine from Autozone. The website should sell them around $150 for 6, much better deal. You might want to pick up a Jeep manual to show you how to get through it. An FSM is your best bet, but pricey, I think around $100. Good luck. If you have anymore questions, shoot me an email and I will be happy to help. There are some vacuum line around the fuel rail that you will want to remove to provide extra room and keep from breaking them.

90red
 
That fuel line quick connect repair kit 90RED is talking about is part number 83502745. That P/N was for my 1987 XJ but I'm sure it's the same for most early 4.0L XJs. Double check the P/N with the dealership. It's around $15 each but makes things very easy. You'll need at least two if you're gonna disconnect the fuel lines at each end of the rail.

Here's a writeup about changing out the O-rings on the injectors. It should give you some idea as to what you're dealing with.

http://www.off-road.com/jeep/cherokee/xjtech/engine/oring.html

Personally I wouldn't take the XJ into a shop if I were you. I'd do it myself. You'll save yourself lots of money and gain experience.

Just be safe and disconnect the battery. It is fuel you're dealing with.
 
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