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Do Injectors age-out?

5K views 32 replies 9 participants last post by  dillon134 
#1 ·
I've got to open up the passenger side and install a new #7 injector. I replaced #4 not long ago. My Excursion has 165K on the original injectors so I'm wondering of I should just replace the other 6 as well. Is there a shelf life on Injectors?

I know most people are reluctant to change all 8 at one time due to the cost. I may have a fuel pressure issue and will resolve that before I drive the truck on the new injectors.
 
#2 ·
Yes. Your truck is continually monitoring you for phrases like, “ I got a raise” or, “we have money left over this month.” It will respond appropriately. Seriously though, they wear approximately the same so it makes sense to replace them as a group. The exception would be a non wear related catastrophic failure. Kind of like how you buy tires as a set unless you have a blowout.


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#4 ·
Yes. Your truck is continually monitoring you for phrases like, “ I got a raise” or, “we have money left over this month.” It will respond appropriately.
Let your truck know that this type of behavior will not be tolerated by purchasing a new truck and parking it next to it. That note comes before hobby truck repairs. :grin2:
 
#3 ·
Lol - nice post RT! Got a good chuckle out of it!

I took his post to mean if he bought the injectors now, but didn't install them for awhile (ie the shelf life question).
 
#5 ·
Thanks guys. By shelf life I didn't mean how long they last in the box/uninstalled, I meant life expectancy in the truck. I probably could have made that more clear.

My main question was is 165K miles considered a lot on an original set or do people often get more miles on them?
 
#7 ·
I saw a video where a guy, as a precaution, replaced the injector hold down clamp/bolts because he was afraid that they had been over-torqued. He said that the bolts are no good after that has happened.

Is that true? The reason I ask is that they seemed a little tighter than 26 ft/lbs when I just removed all 4 from the passenger side. If they were over-torqued then it was my fault but I thought I was careful when I removed, cleaned and re-installed my original injectors a few months ago.
 
#8 · (Edited)
Some people theorize that the head cracking that we occasionally see could be from over torquing of the injector hold down clamps. I am not sure I believe that to be the only reason because we normally see the cracking on the "middle 4" locations (around 3,5 and 1,4 cylinders). Anyway, if it is only "mildly" over-torqued, I wouldn't worry about getting new clamps and bolts.

It is more important to thoroughly clean out the bolt holes and to use a calibrated torque wrench IMO.
 
#10 ·
I used Brakecleen followed by compressed air. Careful of your eyes when doing it.
 
#11 ·
I got 175,000 out of my first set. 150k to 200k seems to be their average lifespan.
 
#13 ·
Cleaning Out the hold down bolt hole....

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#14 ·
Did you purge out/expel all of the oil that leaked in (from the HPO rail) to the cylinder while the injector was out?
Good way to bend/break a lower end part, if you didn't...

~Al
 
#15 ·
Not sure I understand your question. When the oil rail is removed, the injectors are still in place so the oil that drains out couldn't (initially) find its way into the injector sleeves and injector hold down bolt holes. I'm sure that a little oil could and does drain into those cavities once those parts (injectors and hold down bolts) are removed. I know this because I can see a little oil in the bottom of the sleeves.

I've never had the heads out and have never had the opportunity to inspect another 6.0 head up close but don't they have drain back channels so that oil can drain back down into the motor? I remember seeing other posts from guys who had dropped bolts or sockets down that channel and had to get them out.

Are you saying that a lot of oil normally finds its way into the sleeve and then into the cylinder and it needs to be expelled out somehow.

Sorry. I appreciate your comment but want to make sure I understand what your saying exactly.
 
#16 ·
In the 7.3, the oil rail and the fuel rail are incorporated in the head. When we pull our injectors, fuel and oil pour into the cylinder. If you don't suck it out, then rotate the engine with the glow plugs out, you break things. I'm sure that's what Calico was asking - to make sure you have your cylinders completely clean before you reinstall everything and bend a rod.
 
#18 ·
Age out - Shelf Life ?

No, they do not get old and wear is absolutely zero sitting on a shelf. These injectors are an electro- mechanical device who's lifespan is determined by RPM cycles and use severity in cycles. Miles is just an arbitrary quantification because there are so many variables. One user hauling a backhoe every single day and every single mile would have one use resultant, another user hauling the same backhoe once a month another, once a year another likely resultant wear and someone hauling nothing but his grandsons big wheel still another use resultant in the same number of miles.

This is something everyone knows so what does a user do? Keeping and replacing injectors together as a set is an obvious way to keep the group assemblies in the same use - cycle lifespan and expect commonality of condition. Buying a diagnostic system like AE and becoming competent with it would allow a user to gather other data that when looked at and applied to different parameters than miles would allow that user to make a better estimate if injector lifespan.

I use hearing loss to quantify how smoothly and quietly my truck runs. Its getting better and better when my hearing aid battery runs down:grin2:
 
#19 ·
What about the o-rings? I'd expect them to harden with time sitting on a shelf. Not that big a deal for the external ones, but the internal ones would matter.


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#20 ·
Good comments everyone. To be clear, I wasn't curious about them getting old on the shelf, like a twinkle in a wrapper. I worded it poorly. I meant age-out from use ( i.e. how many miles should I expect from the original set).

I believe that others have answered that for me so I'm in good shape. Thanks.
 
#22 ·
Starting Up After Injector R&R

I suppose you could, but that would be only one of two rails. They actually fill really quick, to me the important item is to be certain not to fire the injectors until the oil rails are filled with oil and fuel. Make certain the HPOP is full. To be certain the injectors wont fire; Some disconnect the CPS, I pull the IDM injector relay in the fuse box, turn the engine over for 30 seconds, let the starter cool 30 minutes, turn it over another 30 seconds and let it cool while I put the relay back in and piddle around for 30 minutes. Then it should have charged the rails and start but will run rough for a while getting the air out of the fuel rails.
 
#23 ·
I suppose you could, but that would be only one of two rails. They actually fill really quick, to me the important item is to be certain not to fire the injectors until the oil rails are filled with oil and fuel. Make certain the HPOP is full. To be certain the injectors wont fire; Some disconnect the CPS, I pull the IDM injector relay in the fuse box, turn the engine over for 30 seconds, let the starter cool 30 minutes, turn it over another 30 seconds and let it cool while I put the relay back in and piddle around for 30 minutes. Then it should have charged the rails and start but will run rough for a while getting the air out of the fuel rails.
Thanks for the reply. The HPOP and Drivers Side Oil Rail should still be full - haven't messed with them. I've now had 2 injectors die on me since I replaced all 8 D rings and external o-rings on my original set. However, I didn't follow any particular start-up procedure that time. I'm now wondering if maybe I damaged them because I didn't and that is why I've lost 2 since then.

Either way, they had 165K on them so I'm happy to replace them all. This time I'll make sure to pull the relay as you've suggested. Thanks for the tip.
 
#25 ·
IMO the 6.0L has 3 main issues that affect injector life:
1. Fuel pressure - ford studied this early on and determined low fuel pressure was the #1 reason for early injector failure.
2. Old/dirty oil or wrong oil - spool valve performance and life can be affected
3. Excessive heat - o-rings and seal life is diminished at high oil and engine temps.

The above reasons cause mechanical failure, you can also have electrical failure of the spool valves.

Personally I think the 6.0L injectors should last 200K+ miles. Keep fuel pressure above 50 psig at all times. Keep oil and filter maintenance up, and address any cooling issues immediately and you should see the impact in the injector life. Many people get 250K miles.
 
#27 ·
The FICM does essentially what an IDM does.

Also, the 7.3L CPS is called a CMP on the 6.0L.
 
#29 · (Edited)
How confusing can the owners manual get??? I'm trying to confirm the FICM Relay Location because I want to pull it to prevent them from firing before the oil rail has refilled, as was suggested earlier in this thread. My 05 Excursion has a smaller relay box under the hood, drivers side. I found some pics online that clearly label the FICM Relay. Then, I checked the owners manual and it documents 4 additional fuses/relays that apparently have something to do with the FICM.

Fuse #20 - "FICM RELAY" 20 AMP
Fuse # 103 - "FICM POWER" 50 AMP
Fuse # 105 - "FUEL HEATER" 30 AMP
Fuse # 303 - "FUEL HEATER RELAY"

I've also seen others say that it's fuse 304 but in my manual that is apparently the "HEATED BACKLIGHT RELAY"... whatever that is.

Lastly, i can see nothing in the manual that even discusses the relay box under the hood.

I suppose I coud just pull them all to be sure but how many friggin relays are there anyways #$@#!&#

I've attached some pics I found online:
 
#30 · (Edited)
Its one of the relays under the hood, I forget which one it is (mine is gray) but You’ll know you’ve got the right one when you turn on the ingnition and there’s no injector buzz test.

Also the new fuel pump manifolds don’t come with heaters so I’ve pulled those fuses and relays long ago.
 
#31 · (Edited)
Remember you have a CJB - "Central Junction Box", and a BJB - "Battery Junction Box". The CJB is under the dash. The BJB is under the hood.

A fuse labelled F1.18 would be fuse #18 in the BJB. A fuse labelled F2.22 would be fuse #22 in the CJB.

As you posted, you have:
FICM relay fuse (10A) - fuse #20 under the dash (in later year models this moved under the hood and was numbered as fuse #18)
FICM power fuse (50A) - fuse #103 under the dash (in later year models this moved under the hood and was numbered as fuse #5)

You also have:
FICM logic fuse (15A) - fuse #15 under the hood; note, these are labeled "IDM"
FICM relay (high current) - Relay 304 under the hood; note, these are labeled "IDM"

I believe the fuse and relay numbers for the underhood junction box are correct. That is what they are for my 06, but clearly International wasn't always consistent with them between the model years.

Unfortunately it doesn't look like they included a BJB diagram in the 05 Excursion owners manual.

You want to pull the BJB relay #304.
 
#32 ·
Can't you just use the wire to the starter on the passenger side to crank the starter? That should fill the oil system without firing the ionjector, shouldn't it?
 
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