How long should it take to change a set of injectors on a 4.9/300? Trying to block some time for my Dad's truck.

 

I don't know specifics on the 4.9, but a solid half day (4-5 hrs) is probably a safe estimate. Others may say shorter, but it never hurts to add extra time for those "uh-oh spaghetti-o" moments.

 

I don't know about a 4.9, but on my 5.8 it took me ~2 hours to change them. If i went back and did it again now, probably 45 minutes...

 

Hardest part is making sure you have the right gaskets before you start. You'll most likely need (or want to replace) throttle body, idle air valve, upper and lower intake and egr gaskets. Removing the intake for the first time took me approx 1 hour, reinstall took 20 min. BUT I'm mechanically adept and have a lot of tools, so I'd say a fair estimate is 3-4 total.

Also, before you start make sure you have the correct fuel line disconnect tool, plenty of PB Blaster, and if you have a hard time remembering where vacuum lines go, some tape to label those. AND some extra bulk vacuum hose won't hurt since most likely you'll find some bad vacuum line or you'll break some vacuum line during the process.

 

Anywhere from 1hr to 10hr. It really depends on the level of corrosion, who's doing the job, and the working conditions (in that order).

You'll need PB, that's for sure. I'm sure you know, aluminum and iron (steel) become very hard to separate once they've corroded together and one broken bolt will screw you over depending on where it is. If you're changing injectors then your special tools are the search bar on YouTube and a business card sized piece of tin flashing or similar material.

Removal will vary depending on how much smog equipment isn't in your engine bay but it generally goes like this:

-get 12 fuel injector O-rings (about $8 at NAPA IIRC), PB, upper intake gasket (IIRC sold as set w/ lower) and dielectric grease.
-get your tin business card, gloves (so you can actually use the tin business card) 8mm (for the hose clamps and all the other engine bay stuff), needle nose pliers, a flathead screwdriver, 7/16, 1/2, 9/16 sockets and a 3-6" socket extension (for the front fuel rail bolt and the driver's side of the plenum)
-make sure you have a 1/2 DEEP socket
-get the stuff to DIY a new ground strap (dig through the trash for something with a heavy cord) because it's easier to DIY a new one than worry about breaking an old one.
-spray everything with PB
-disconnect intake hoses
-unplug vac stuff and tuck it out of the way
-unplug electrical stuff (using the flathead and pliers to avoid breaking things) and tuck it out of the way
-unplug the PCV
-pop off the throttle cable
-disconnect the studs holding the intake on. (I find the rear one is best reached while standing on the hub and leaning over the fender.)
-disconnect the bolt holding the TB side of the plenum to the bracket attached to the head.
-lift the upper manifold off and collect the parts of the gasket (so your lower intake doesn't collect them for you)
-use your "special tool" to disconnect the fuel lines from the rail
-use your 7/16 socket to remove the rail bolts
-rock the rail/injectors out. Some injectors might come w/ the rail, some might stay in the manifold.

installation is mostly reverse of removal (if you're competent then you can figure it out, if you're in over your head then it sucks to be you)

Replace the intake hoses w/ something smooth if you feel like it. Bendy straws don't exactly promote good air flow.

If this is the first time most of this has been unplugged then hit all the electronics with battery terminal cleaner let them ferment and then scrub them with a toothbrush and slap on dielectric grease before reassembly. Most "bad sensors" on our trucks are the result of people unplugging connectors that haven't been unplugged since Clinton was president and then plugging them in and expecting a perfect connection.

I've had the manifolds on my 300 on and off more times than I can count. Pulling the upper takes me about 10min at this point 1hr to pull the upper seems reasonable if all the smog stuff is intact and you've got OE rust to fight with. EGR itself probably adds about 40min if it's never been moved.

Since it's your dad's truck I'd recommend changing or cleaning the PCV while you're there. If you have EGR to remove I'd remove it at the top of the tube rather than fight w/ removing the old gasket on the manifold. The TB and IAC gaskets are rubber and I've reused them many times. I'm sure some electrical tape would work in a pinch.

I've never seen an OE ford fuel injector fail and I take it that gramps isn't swapping bajilion lb/hr injectors for some less than well informed reason so I'd like to ask why you're changing injectors?

 

Most likely I'm guessing his injectors are leaking, if that counts as "failing" to you I've seen that happen plenty lol. I have to change mine before I go to emissions testing because they are leaking horribly. Maybe if they get here before you start I'll take some pictures and post them up as a brief guide for the OP to follow.

 

IF you have small hands and can twist into a pretzel, you can change the injectors out without removing the upper intake. That way takes about 2 hours and avoids the EGR and fuel connector issues. I did it before with help of small hands though....

3 to 5 hours depending how things come apart with EGR pipe(soak it with PB blaster or equ for hours helps!). You don't really have to disconnect the fuel lines, just move it up off the injectors.


What's wrong with the injectors requireing changing out?

 

167,000 miles, poor fuel mileage, poor horsepower. I did most everything else, so by the process of elimination I'm trying the injectors

 

Before changing injectors out, check the fuel pressure with engine running then shut off engine and watch how the fuel pressure drops. Most trucks should hold pressure for about 3 to 5 min before it bleeds down.

Also what parts were replaced? Was the O2 sensor replaced? That sensor will cause poor MPG and preformance when it goes bad, bad enough to make the ECU run rich without setting codes!

 

No O2 sensor was not replaced.
Seems my parents didn't want to wait for me to get some time and took it to a shop. They got raped at the shop and will allow the mechanic to retire early.


How do I check the O2 sensors??

 

If the truck's over 60K mile and no history of it being replaced, best replace it. You can test a O2 sensor with a volt meter. There's a few threads about that.