4.0 Fuel injector

Within a week of getting my 88 MJ ihad 2 of those suckers pull that on me. Did you happen to notice hwere that fuel runs as it leaks out? Yep, right down on the exhaust. If you have fuel around the electrical connector, they are toast - replace them. Of course, you should also replace ALL the o-rings (12) when you replace the injector

- and don't forget the ones for the feed line and the pressure regulator. You have to pull the fuel rail anyway, so it's cheap insurance.

I bought the aftermarket > BTW, I passed on the 266k YJ.

Tx for the advice. How do I pull the fuel rail?

Carl

There are bolts that hold it down and clips on the injectors. Also there are o rings on the fuel rail that can get lost. Be careful with those as well. You need a manual it sounds like. there is also fuel pressure to bleed off before you yank it apart. KH

Kevin makes a good point - a manual will save you serval times it price over the life of a Jeep.

You don't necessarily have to pull the fuel line on the 88/89 but it has a pressure regualtor sittin at the front end of the rail attached to the return line. You can loosen the clamps that hold the return line in place to get enough room to work, but it's easier just to pull the regulator off the rail before you start - take the O-ring that seals it to the rail with you and get a new one at the store while you're there - make sure it's rated for fuel line use. If you DO pull the fuel line, also pick up a package of the plastic clips to use when you re-install it.

There are 3-4 small bolts that hold the fuel rail on the manifold. They may be stuck and take a pretty good pop to start out of the aluminum threads, but don't carried away when you put them back - good and snug but hauling away on the wrench will strip threads. Short screws into aluminum are touchy.

A sh> Tx for the advice. How do I pull the fuel rail?

To ammend the above, use NeverSeize on fasteners going into aluminum (unless specifically forbidden). Buy the big bottle. Use it on everything.

For exhaust manifold bolts and studs, use pipe dope. The gritty or chunky looking stuff is *much* better than the smooth and creamy. Pipe dope doesn't cook out like NeverSeize (even the alleged high-temp variety ain't so great).

John

Carl Saiyed did pass the time by typing:

1) release pressure at the test port 2) remove the screws holding it in 3) slowly work the injectors out of the manifold (grab and twist, it takes some effort) work one at a time to minimize stress on the rail and don't use the rail as a handle, it's more expensive than the injectors. :/ 4) get a glass jar ready, the rail holds lots of fuel and there isn't any sense in wasting it. (not at todays bloody high prices) 5) pull back the fuel return line and supply line (some use clips, some use a spring lock, YMMV) and remove the lines. 6) take the rail over to that glass jar you have 7) Remove the clip from the back injector and with the fuel rail ports stuck in that glass jar you have.. :) slowly wiggle the injector free. 8) take the rest of the injectors off. There will be quite a bit of gas left in the rail and injectors.

hint: it's better to work on the clips while sitting on the garage floor. things that fall a short distance tend not to bounce very far. :)

I use a toothbrush and some TB cleaner to clean the rail ports and manifold ports. To put the injectors back you just do the reverse, a bit of oil on the o-rings will make it easier to slide them in. Try to keep even pressure on the rail (work one injector a bit at a time)

The rail bolts don't hold back any pressure. Use a nut driver and when they seat give a bit more.

Thanks all. I was able to replace just the 12 O-rings. The injectors didn't look fantastic but didn't look bad. I was able to wrestle the clips off without removing the rail from the return line. Is anything wrong with GP-Sorenson injectors? Autozone has them for $45, while CSK has Niehoff for $76. Are all injectors made equal?

Carl

L.W. ("ßill") Hughes III did pass the time by typing:

I'll do that.

But now it's time to log off. My UPS went POOF and there is a thunder storm in the area.

Toto? KH

Kevin in San Diego did pass the time by typing:

I hope not.

The UPS failed yesterday and that means I have to plug the PC into ye olde power strip.