Replacing Injectors On 1999-2003 7.3L Power Stroke Diesels

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Loosen plug on back of head to drain fuel. Remove intercooler tube and valve
cover. Unplug injector and remove oil deflector on top side 8mm bolt.

Remove 8mm bolt on lower side. pry up on injector to remove. Oil will
drain into cylinder. I use a vacuum evac system to suction the oil out. You can
stuff a rag in and absorb as much as possible. Crank engine with ratchet at
least two revolutions and absorb as much as possible.

Unplug UVC harness
both sides and remove fuel pump fuse. Crank engine with starter to blow out the
rest. Bump the starter slowly at first so you don’t hydraulic a cylinder. Oil
o-rings and install injector. Bump it with the palm of your hand to seat it.
Tighten injector to 10 ft lbs. Remove oil drain plug in cylinder head. There are
two in each head, under valve cover between injectors. Should be 1/8 allen
wrench size. Tighten fuel drain plug.

Fill hpop with clean oil. Crank
the engine until oil is pumped out this plug. Reassemble as removed. The engine
will crank for a while until the hpop builds pressure and will run rough for a

Helpful Tips From Another User For This

Don’t mess with the plug on the back of the head unless you
want to. There is some fuel in the rails but it can be dealt with pretty

First pump the oil out of the high pressure oil pump reservoir.
It’s about a quart or so. The plug on the top can be removed for the Mity Vac to
gain access.

You do need to remove the plug that is on the head that
leads to the high pressure oil rail. It is drilled in-line with one of the
injectors and faces the lifter valley. You will want to use the Mity Vac to suck
out all the oil in the head, it will be another quart or so.

Get three
rags or paper towels. Have them ready to go, sitting right there next to you.
The second you pull the injector, stuff a rag into the hole. Wait 5 seconds.
Pull that rag out and stuff another one in there. Wait 5 seconds. Pull it out
and stuff the third one in there. Leave it there for now. Between pumping the
oil you can out of the rail and the rags soaking it up, you will have captured
about 90% of the fuel and oil that would have drained into the

Mity-vac what you can out of the cyl and also pull the glow plug and
turn the motor over by hand a few times with a breaker bar. A nice little mist
will spray up and out letting you know it’s ok to put the glow plug back in. It
is an excellent time to put in new glow plugs.

Before you put the
injector back in, spray a little brake cleaner down the hole. It will blow any
tiny bits of build-up down into the cylinder so the copper gasket on the new
injector can get a good seal.

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