update-GONE BAD!!!diag/replace of fuel injector? | Ford Explorer Forums - Serious Explorations

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update-GONE BAD!!!diag/replace of fuel injector?


Active Member
July 10, 2008
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Year, Model & Trim Level
2002 4.0 4x4
:mad:Anyone have a way to diag and replace if neccesary?

Been fouling plug on cylinder #5 for a while now. Replace it every few months until now it fouled right away. I suspect a leaking or bad fuel injector but dang its hard to get to those things on a 2002. Under the intake manifold. I can't even get a stethascope on the thing! I ordered a service manual but its not here yet and I need this thing fixed before weekend to pull my trailer.

Anyone have a writeup or advise? I tried the search function with no luck.


2002 explorer eddie b,4.0L

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The replacement procedure is as follows:

1) Disconnect the negative battery cable.
2) Remove the upper intake manifold and it's associated components (8 Torx bolts, two rows of four.)
3) Release the fuel rail pressure.
4) Unclip the injector plugs.
5) Disconnect the fuel rails (supply manifold) from the injectors.
6) Discard the injector-to-supply manifold O-rings.
7) Remove fuel injectors from lower intake manifold.
8) Discard injector-to-intake manifold O-rings.
9) Replace both sets of O-rings with new sets (lubricated with clean engine oil).
10) Reverse the disassembly process.


Looks like my post was beaten - refer to the prior one.


You guys rock! thanks. Got the manifold off. Now just figuring out the fuel rail.

yikes that was a big job. Hope I can get it all back together when done :)

sad thing is I think it was all for nothing. They all ohmed out to same spec. Still looking for my misfire.

This area of the engine was indeed filthy though! Oil grime all over caused by a thermostat leak year ago that I couldn't clean up under the manifold well. Taking me forever to get it all clean.

What exactly did the fouled plug look like?

ignore the broken part :) it was stuck. Took 2 of us to finally get it loose. Carbon fouled?


Looks oil fouled to me.

yes, that's what I meant. Definetely oil fouled. Guess I will clean them all out with carb cleaner and reassemble. Maybe they just got dirty from the mess on top of the engine. If not, this on may have to go to a repair shop. Diagnosing is most of the battle for me.

anyone know where this hose go's? It starts at the neck of the intake manifold by throttle body. My finger is pointing to it. All put back together except this one lone hose. Looks like it connects on drivers side wall somewhere.


oh crap

Ok, found out where the hose went in the daylight. I need to get out of the auto mechanic business. Was feeling good after a easy water pump install.Got it nice and clean everywhere. Cleaned the heck out of the fuel injection area which was filthy. Cleaned injectors with carb cleaner. Not that dirty. Put it all back together and it runs like crap! Engine shakes bad and you can hear something in the engine like a rod or something now!

Again the original problem was a misfire that kept fouling a plug. I moved the injectors to the opposite side of engine to see if a different cyclinder started misfiring. Now its everything! Could putting the manifold on wrong cause some of this? I didn't use new gaskets or anything. Old gaskets were pretty much flush with the manifold. May need to change those. Guess I should make sure no spark plug wires came loose in the meantime also. I did lay a board across engine to get to the back of the manifold. I am so done with this thing.

Yes, you should have used new intake manifold gaskets.
Check for vac lines not plugged in or broken.
Check firing order of your wires.
Are the injectors all plugged back in?

Triple check your wires and firing order, as mentioned:



Its alive! After a camping weekend came back and checked all wiring etc. Found a vacuum hose that came loose close to the engine block on passenger side. Fuel pressure seemed to pressurize. Stumbled a bit at first and then started to idle ok. Not perfect but good. Could be the anti-fouler installed. Drove it to work this morning where it smoked a little for the first 10minutes. Probably some burn off from all the cleaning I did I hope. Then it stopped smoking and ran great! Crossing my fingers its fixed, but time will tell. Thanks for all the help! Hope I can return it someday.

Update. Code was still on and a slight misfire. Did a compression check and found some differences in cylinders. Ran a can of k&w head gasket repair through it and it seems worlds better! Code still gone. Hopefully that does it.