Injector O-ring Replacement

My injector on my '90 4.0 closest to the fuel pressure regulator seems to have a bit of a leak to it, and I suspect the O-ring. I plan to replace them all while the fuel rail is out. My Hanyes manual says that when the fuel line quick-connect is disconnected at the fuel supply line, the quick connect is junk and needs to replaced. Is this B.S.?

Do I even need to dissconnect the fuel supply line to the fuel rail?

What's the easiest way to change the O-rings?

Thanks in advance for any help.

Injector

You can remove the fuel rail with the fuel lines still attached. It can be a little hard, but can be done. The line near the firewall is flexible, the line near the front of the motor is metal and not flexible. The way I got around it was to lift the vacuum cluster on the intake (be careful not to break any lines!). There is a stud under it that holds the bracket that holds the vacuum cluster in place and also holds the metal fuel line. You can remove the nut on the stud and remove the bracket. This will allow for some play in the line. If the injectors and o-rings are original, or have many miles, they are probably going to be hard to get out. When you install the new o-rings make sure to lube them. I used A/C PAG oil when I changed mine. Also, double check and make sure its the o-ring and not the injector itself. I had the same thing happen to me. I thought the o-rings were leaking, changed them, still leaking. Finally figured out it was the injectors themselves leaking. Replaced the 3 that were leaking and the other 3 started leaking about a week after I installed the new ones. Not strying to scare you or anything, just the way it happens sometimes. I also have a 90 4.0. My 90 has 215,000 mi. on it, so you might not be as bad off. Good luck with your XJ.

90 red

The injectors on the pre 91s are prone to leaking at the plastic metal seam. When one goes the others soon follow per my experience and the above post and per my long time dealer tech writer. Many have had their early xjs burn up as a result. Replace all your injectors now. Do not use oem injectors. Many use the 19lb ford injectors from the 5.0 ford V8 mustang. Our stock injectors (pre 91s) are about 18.6lb injectors. You can get used mustang take offs for cheap or get some fordmotorsport injectors with the better 4 hole spray pattern from summitracing.com. Don't become a Zippo lighter!! Good Luck. Greg

I did mine last week and just pulled the fuel rail off. It made more work, but the parts were cheap enough so I figured why not replace them. Looking back I kind of wish I replaced my injectors at the same time with the mustang injectors greg talks about, but what else can I say other than hind site. I've heard from a couple people that at higher milages if you replace you injectors some see noticable improvements in MPG's and performance, but I cannot speak to this personally.

Just to echo what everyone else says, think safety!

O-rings are a jeep dealer part only if I remember correctly about $10 worth of little orings. I had this occur and replaced my injestors at the same time but they had 200000 miles on them. The rings and new quick connects (GET NEW ONES AT AUTOZONE) total about $15. Add injectors from autozone and your looking at $25-$35 per injector ($75 from the dealer).

BE CAREFUL WHEN REMOVING THE RAIL. Have patience when removing the rail. Wiggle while applying pressure. If you damage it you could create even more of a potential fire hazard.

Carb shop

The carb shop in my town will ultrasonically clean injectors to good as new. They have specialized equipment to disassemble and test them for flow rate, spray pattern, leakage, etc. It was $25 dollars a piece, new o-rings included.

Hey Markm - what's the P/N for the disconnect kit, and who makes it? I've enjoyed "limited success" finding them in the aftermarket, and jobber at the local dealership is still about $13...

5-90