Best method to install fuel injectors in V-8 engine? | Ford Explorer Forums - Serious Explorations

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Best method to install fuel injectors in V-8 engine?


Well-Known Member
May 18, 2007
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City, State
Year, Model & Trim Level
2002 Limited 4x4 4.6L
I have a V-8 and because the fuel rail assembly is U-shaped the fuel rail with injectors connected can be a little unwieldy when handling it.

1. Is it better to install the fuel injectors into the ports first then after all 8 injectors are in snap the fuel rail on top of the injectors.
2. Is it easier to install the injectors first in the fuel rail then attempt to install them one at a time into the engine ports?

I'm just a little concerned that with option #2 the dangling fuel injectors will bounce around and get crud all over the tips before I can get them in the ports.

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I do option 1. The injector rail is usually bellmouthed at the injector opening, making it easier to lay the rail over the injectors after they are in the head/intake. I worry about nicking an o-ring doing it the other way.

Option 1 has been the easiest for me.

If you install the injectors into the intake manifold first, does it make sense to install them before you bolt down the intake manifold or should the manifold be bolted in first then the injector inserted?

you probably have more space to work around if you bolt the intake manifold first. Also the reason I have option #2 is because I pulled the rail with the injectors in place (or still attached), I just simply put new o-rings and slap them back without rotating or re-aligning them again (not sure if positioning the injectors once their in will ruin the o-ring)

Since I'm replacing the intake manifold, due to a coolant leak, the job requires removing the fuel rail and injectors. I was going to just clean up the injectors and replace the o-rings but decided that since it's a rare opportunity to have the fuel injectors in hand I might as well have them professional cleaned and tested.

I'm fortunate enough to have an injector rebuild service located a few miles down the road so I dropped them off there and picked them up the next day. Cost out the door was $90 to clean, test/rebuild the 8 injectors. They do an initial cleanup then ultrasonically clean them while actively cycling them. The micro screens are replaced as are the o-rings. Then they put them on the cleaner/tester to get them ultra clean, test for flow/pattern and reclean as necessary. They are metered to verify they are consistent within tolerance across the 8 injectors. The solenoids are checked and they are leak tested. With 150K miles on my Explorer after 14 years I figured the $90 was worth a one time thorough cleaning and this type of cleaning is better than having Jiffy lube hook the vehicle up to a machine.

The Chilton manual says to use motor oil as the lubricant for the o-rings. I know some folks use the Dow product as well as Vaseline.

Clean Motor oil should be fine.

I just like the Dow 55 because I use it for work all of the time and have never had any problems.