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Leaky Injectors

kellen

NAXJA Forum User
Location
Seattle
I have an 89 Cherokee Laredo, I6. I was driving and the smell of gas entered the cabin. So I checked the injectors and the second one (from the front of the engine, #5 I think) is leaking. Now my questions are;

Is my problem probably an injector or an o-ring, it seemed to be leaking from the top of the injector, where that metal clip was, near the fuel rail. I know the answer is it could be either, but I am trying to get a $$$$$ idea.

is there a normal life span of injectors?? I ask because if I am going to pull an injector, is it even worth it if car has 100K on it?

Should I replace all of the injectors if this is the problem, or just the one that is leaking?
Finally, should I even take it in to someplace to have them look at it? I feel that I can do it, but will a shop be able to tell me if it is the injector or the o-rings, or are they just going to replace the o rings first, then check to see if the leak is still there (which I can do).
 
Most likely it is just the o-ring on the fuel rail. Look at your injector real close and see if the fuel is coming from the rail or if the plastic is cracked at the top of the injector. Either way you are going to have to pull the fuel rail to fix it. It’s not hard to do, just a little time consuming. You have to pull all of the stuff off of the manifold (TB, air tube, cable bracket) before you can get to the rail. Be real careful when you disconnect the file lines from the rail. GENTLY squeeze the quick disconnects and work them back and forth till they come out. The rail has a couple of bolts that go into the manifold. The hardest part is pulling the rail off of the injectors/out of the manifold. I had three injectors that stuck in the manifold and three that stuck in the rail. After that it is just a matter of pulling the guilty fuel injector and either replacing it or the o-ring. Assemble in reverse order. The o-ring kits are pretty cheap ($2 or so a NAPA, you will need 6 to do all of the injectors) and the injectors are around $60. Or you could just replace them with a whole new set from http://www.fiveomotorsport.com/Injector_SetsJEEP.asp Either way, I’d get that fixed pretty quick. Fuel leaking onto a hot manifold is a recipe for disaster.
 
Service life of the orings is 100K or so, for the OEM injectors about 150K (for the RENIX units, and that's what you have.)

If you are going to change one oring, CHANGE THEM ALL! You've got to tear the rail to bits anyhow, and you'll feel dumb when you do the job again in a week or so because you didn't do it all the first time...

For injectors, the $60 price tag is about right for application-specific injectors. However, the common Ford 5.0/302 injectors flows about 19# @ 39psi (same as the RENIX units) and you can get six plus a couple spares for about $200. Wish I'd know that last time I had to change them... LOTS of good reports from the field on the 302 injectors, so I'll do that next time I need a set.

Check the source of your leak carefully - the factory RENIX injectors have thei service life I mentioned simply because they tend to start leaking at the body seam right below the electrical connector. Look around, there have been a few engine fires caused by not paying attention here!

The oring kit went for about $13 at the dealer (last time I got three or four, so it's been a bit. Always keep small critical parts handy!) but should be about the same now. There's a kit of 13 rings, don't forget to change the one in the regulator.

When you change the rings, drain/depressurise the fuel system into a cup and dump the orings into that before you tear everything apart. Let them soak while you work, and as long as you watch corners on things you won't "skin" them on the way in. Soaking them in fuel will give you a better seal than putting them in dry (don't ask me how I know, suffice it to say I've been to this barbecue before...)

5-90
 
Ditto the above, plus ...

Do NOT take it anywhere like that! Do not drive it at all. I watched one XJ burn up in front of a former GF's house from this. A NAXJA member a couple of years back knew his injectors were leaking, drove to the dealership to buy the O-ring kit, and the Jeep burned up while he was in the parts department.

This is not something to be trifled with.
 
I bought a set of new Ford injectors from Fiveomotorsports for an '87 Cherokee. Install was not to bad and. I didn't even have to remove the throttle body. They've run great for a couple months now. I think I paid $149. Deffinately worth the money. I thought about doing orings only, but I didn't want to do the job twice.
 
I'd recommend fiveomotorsport.com as well; I picked up new injectors for my 96 because of a leak when I replaced my exhaust manifold
 
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