Leaking fuel injector?

Alright..so last weekend I decided to change the spark plugs on my 2000 xj 4.0 for the first time. I was tired when I started and had copies of the FSM printed out. Unfortunately, I got confused and thought the fuel rail was the coil rail. So I unded the four bolts and started to pull it out. Once the injectors came out of the holes, I realized that I had totally screwed up. Slightly panicking, I reinserted one of the o-rings (on a different injector than the one that is leaking) and pushed the coil rail and injectors back into place and bolted everything down.

A week later I've been noticing a wet/damp spot that looks like its coming from the third injector from the front. It doesn't smell like gas, can't really figure out what it is. When I rev the engine while standing in front of it I can't see anything leaking.

Any advice as to what I should do? Is this dangerous?

Fuel leaking over the top of the exhaust manifold = XJ barbecue.

I would clean the area and keep checking it. Daily, at least for awhile. Old school, use some baby powder around the injectors, most will blow away but enough should remain to show any fluid trails.

Yeah I thought it might be kind of dangerous. I just got back from a 400 mile round trip to vermont and noticed that the spot got bigger. The thing is is that it isn't wet but it's slightly damp.. like I took some dirty hi-temp grease and lightly spread it around in the dirt. I'm guessing a tiny amount of fuel is leaking and hitting the exhaust manifold and evaporating.

The one thing I didn't do is use my torque wrench on the fuel rail because I didn't have the correct torque (or deep socket) handy. I'm guessing the smart thing would be to go and loosen all the bolts and retorque everything. I was so freaked out that I pulled the coil rail out I was just happy to get it back together and running. Then of course I totally forgot about it

You might consider pulling the fuel rail again, and put a little swipe of vaseline on each of the injector seals and re-seat the whole thing.

Could this cause a significant loss of MPG? This popped up after I had mine off replacing the header/intake gasket and now am trying to track the cause of a major mpg loss

Do I have to go through the process stated in the FSM of relieving fuel system pressure etc. or can I just unbolt the fuel rail, pull it back, lube up the o rings and put it back in place?

Emerscape said:

Do I have to go through the process stated in the FSM of relieving fuel system pressure etc. or can I just unbolt the fuel rail, pull it back, lube up the o rings and put it back in place?

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I don't know on your year, but on my Renix I could simply unbolt the rail and lift it enough to clear the manifold so I didn't have to depressurize the system.

Baja_XJ said:

Could this cause a significant loss of MPG? This popped up after I had mine off replacing the header/intake gasket and now am trying to track the cause of a major mpg loss

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If your injector seals are leaking and allowing excess air into the system then the o2 will read lean and the PCM will increase the injectors duration to compensate.

joe_peters said:

If your injector seals are leaking and allowing excess air into the system then the o2 will read lean and the PCM will increase the injectors duration to compensate.

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So should I just replace the injector O ring or install a new injector?

Baja_XJ said:

So should I just replace the injector O ring or install a new injector?

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I would try and replace the o-rings first.

Also, here is a link to an XJ three part mileage article:

MPG:


http://www.jpmagazine.com/projectbuild/154_0808_building_a_fuel_efficient_jeep/index.html


http://www.jpmagazine.com/projectbuild/154_0810_building_a_fuel_efficient_jeep_part_2/index.html


http://www.jpmagazine.com/projectbu...cherokee_xj_project_mileage_master/index.html

I found their loss of MPG due to a failing P/S pump very interesting.

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The one thing I didn't do is use my torque wrench on the fuel rail because I didn't have the correct torque (or deep socket) handy. I'm guessing the smart thing would be to go and loosen all the bolts and retorque everything. I was so freaked out that I pulled the coil rail out I was just happy to get it back together and running. Then of course I totally forgot about it[/QUOTE]

Not torque-ing the bolts would not be causing a fuel leak.One of the injectors has come loose in the fuel rail.
As long as the bolts were tightened down by any amount that is fine,the O-rings are whats loose.

Wayne

If you can't tell the difference between spark plugs and fuel injectors, maybe you should hire it done instead of fumbling around under the hood. Be careful please!

Emerscape said:

Do I have to go through the process stated in the FSM of relieving fuel system pressure etc. or can I just unbolt the fuel rail, pull it back, lube up the o rings and put it back in place?

Click to expand...

There are O-rings on the top and bottom of the injectors,to replace the top O-ring a clip must be removed and the injector pulled out of the fuel rail--a un-pressurised fuel rail would be a help.

Wayne

Bottom line I shouldn't been working on my jeep when I was tired.

Anyone know what size socket for the fuel rail bolts? I need to get a deep socket and it would save me a ton of time rather than trial and error.

Home Depot has a full set of deep + shallow metric/SAE sockets plus some extension bars and sparkplug sockets and such for $50 or so total. It's Husky (ie their semi ok store brand) but other than the ratchet it's pretty good.

thanks I'll check it out. In the meantime does anyone know the size? I'd rather not run back and forth trying to figure out what size it is.

I've got a good parking spot outside of my condo (so I can work on fixing this) so I'd rather not move my car to go to home depot.

10mm

Check the recesses in the manifold- a couple of mine were built up with gunk, and I had to clean them out in order for the new Orings to seat fully.

Check the recesses in the manifold- a couple of mine were built up with gunk, and I had to clean them out in order for the new Orings to seat fully.

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Ah..wish I had checked this post before going out and replacing the o-rings.... I went out yesterday, cleaned out the areas around the injectors the best I could (with a paper towel), unbolted the fuel rail and pulled out the injectors. I then pulled off all of the o-rings (one was torn, not leaking though, and the rest were fine). I then wiped off each injector and used a paper towel and my pinky finger to wipe out the injector holes, but I wasn't really aggressive about it. Then I put a little bit of vaseline on each o-ring and installed on the injector. Once installed, I wipped off the injector and o-ring in case there was any grit on it, and put a little bit of vaseline on each o-ring again. I then pushed the fuel rail and injectors into place and torqued to spec.

I started the jeep up and let it idle for 15 minutes. I noticed some "stains" around the 1st and 6th injector but I couldn't tell if they were from my greasy hands when I was installing the o-rings and injectors or whether they are weeping. I took the jeep for a ride later on and didn't notice a change in the spots, but I'm slightly paranoid. It's not like it's wet, so I can't wipe it up and smell fuel but I'm wondering if I should be concerned by the stains?

Can anyone recommend a good cleaner that I could use to get rid of the "stains" and see if they come back? I think joe mentioned using baby powder, can I just sprinkle that all around the injectors or what?

Thanks for the help.

You can lightly dust the area with baby powder and see if any tracks from moisture form.

For cleaning the engine and surrounding area I use a 50/50 mix of Simple Green and water in a pump garden sprayer (dedicated, I don't use the Wife's pesticide sprayer) and lightly wet the engine and after 10-15 minutes use a garden hose with low pressure to rinse things off, BEING CAREFUL to not wet the TPS on the throttle body.

ah.... the one thing that kills me about living in the city. I grew up on a farm with tractors and every tool imaginable. Now I live in a concrete jungle where a simple garden hose is few and far between.

Obviously I can improvise, but sometimes I miss the simple things.

Thanks for the help. I think I'm just being paranoid about it, but I'll clean the area this weekend and see what I can find out.