Here's a potential stumper for you.

[Tweeder]

I've had a strange misfire like event when cold all winter. ended up getting a job with a company vehicle in late December so I haven't really worried about it for a couple months, haven't been driving 80 miles round trip to work; been driving the truck randomly and haven't really felt the issue, but I only felt it on long runs above 50mph anyway. All city driving since mid-December. Spring and Summer are on the way, and so is camping season and I have finally decided it's time to square this truck away; have my lift and gears ordered and need to make sure this thing is tip-top before I install them.

All my PID's look good, no misfires found, etc. Had a buddy hook up to FORD IDS and another buddy had AE. I have Forscan; none of these systems have found any issues present. No codes are in this truck at all, and the contribution tests done on both IDS and AE came back as no cylinders more than a fraction of a percentage off any others. All actuators, valves, FICM, and everything else are within specs. No issues at all are registered with the ECM. All contribution tests, and other testing were done in November.

Here's the stumper. I decided to run outside today since it's a nice day here, and plug in with my Forscan and play with the truck. No codes are present at all. Last scan was done in November, and no codes have been present since September 2020.I decided to cut cylinders off one by one. When I cut cylinder 5 out; there was almost no change to the idle, RPM, or sound of the truck. All other cylinders clearly changed idle, and sound; and also caused a vibration that was noticeable. Cylinder 5 did none of these things. In my mind, I'm instantly thinking, injector 5 must be going out, but how would a contribution test come back clean. If there was a gasket leak, or something mechanical with that cylinder, it would likely be constant, and also cause a contribution issue. I did a fuel bowl bubble test in November and this thing didn't cause any bubbling, so I know I don't have a bad seal there. I also noticed that during KOEO buzz test that cylinder five did not respond at all during the individual buzz test, but did fire during the all cylinder cycle of the test. The test came back as "Passed, no issues found" so that confuses me.

So, I'm faced with injector, FICM, Harness, what else is there? Where would you all start? My buddy with IDS moved away, and the dealership wants $400 to do another contribution test; assuming the tard behind the desk even knew what I was talking about; which I'm not confident that he did. So, where to start?

Truck is an 05 250 with just over 195,000. I had injector 8 replaced about 6 months ago, but I'm assuming that the others are originals. There is no smoke, minus the puff of white at start up, the off idle puff of black. No unusual fragrance, and no loss of fluids. I mean none. 5000 miles and it's barely lost 1/8 of a quart of oil (I do have a random oil drip from somewhere on the back of the oil pan), and hasn't lost any coolant since I bought the truck in April last year.
So, the question: where would you start? Which part-dart would you throw?

Thanks.

 

[6.0 Tech]

Sounds like stiction. I’d replace the injector and go from there. Have you done buzz tests when it’s cold, prior to firing it up? That will typically point you better. Any injectors that don’t click or have a muted/dull click you should replace.


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[Tweeder]

Anyone who has Forscan and wants to exercise your brain and spend an hour. I uploaded my scans from November, and today.

 

[Tweeder]

Sounds like stiction. I’d replace the injector and go from there. Have you done buzz tests when it’s cold, prior to firing it up? That will typically point you better. Any injectors that don’t click or have a muted/dull click you should replace.


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That's what I was thinking. Todays test was cold. Truck hasn't been driven since Thursday. I did the buzz tests before starting the truck to play with the programs. This is my first 6.0. SO do these trucks tend to pass tests while there's a problem? A failing injector certainly makes the most sense at this point, but why would a buzz test pass even without the injector actually cycling? Or is it possible it was just too quite for me to hear it?

 

[6_Riders]

That's what I was thinking. Todays test was cold. Truck hasn't been driven since Thursday. I did the buzz tests before starting the truck to play with the programs. This is my first 6.0. SO do these trucks tend to pass tests while there's a problem? A failing injector certainly makes the most sense at this point, but why would a buzz test pass even without the injector actually cycling? Or is it possible it was just too quite for me to hear it?

To quiet, which also means failing.
Unplug that one injector and double check that the wires are properly seated into the connector. The wires can "slip out of" their locks on the plug and not fully seat when plugged in.
Also, imo, and if it's affordable, replace the whole bank. No reason to do the job 4 times (or twice really). If it's not within the budget (and I don't mean you being cheap, I mean, you'll starve if you buy more than 1 injector) then, by all means, replace just the one..... You can also swap plug positions to see if the problem stays at the injector or follows the harness.

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[6.0 Tech]

That's what I was thinking. Todays test was cold. Truck hasn't been driven since Thursday. I did the buzz tests before starting the truck to play with the programs. This is my first 6.0. SO do these trucks tend to pass tests while there's a problem? A failing injector certainly makes the most sense at this point, but why would a buzz test pass even without the injector actually cycling? Or is it possible it was just too quite for me to hear it?

The codes the buzz test will set are if there is an electrical fault. It has no actual way of knowing if the spool valve cycled or not, just that it told it to and it saw the correct amount of fly back voltage. If the spool valve is stuck, the injector will not work, but it will not throw a buzz test code. It may throw a contribution code while its running if the misfire is bad enough, but not always. With the buzz test passing, I’d say replace any of the injectors that had no or a quiet buzz, and go from there, or as was said, replace the whole bank if you can. It will save you time down the road.

A third option that I am not sure of on success, but there are people who swear by it, is put some revx or other supposed stiction eliminator in, with a fresh oil change, and see if that fixes it. Personally, I’m for fixing stuff correctly, but if this works it would be cheap and easy compared to swapping injectors.


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[lincolnlocker]

The codes the buzz test will set are if there is an electrical fault. It has no actual way of knowing if the spool valve cycled or not, just that it told it to and it saw the correct amount of fly back voltage. If the spool valve is stuck, the injector will not work, but it will not throw a buzz test code. It may throw a contribution code while its running if the misfire is bad enough, but not always. With the buzz test passing, I’d say replace any of the injectors that had no or a quiet buzz, and go from there, or as was said, replace the whole bank if you can. It will save you time down the road.

A third option that I am not sure of on success, but there are people who swear by it, is put some revx or other supposed stiction eliminator in, with a fresh oil change, and see if that fixes it. Personally, I’m for fixing stuff correctly, but if this works it would be cheap and easy compared to swapping injectors.


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Right. All rev x does is thins out the oil.... better off using a good 10w30..


With that many miles, id just put a good set of 8 injectors in it...

live life full throttle

 

[bismic]

I have done a few oil analysis with the stiction additive in my oil (only out of curiosity). While it does SLIGHTLY impact viscosity (maybe 1 percent), it is not a significant impact. It has detergents in it as the primary "active" ingredients.

I have 230k miles on my original injectors and still no signs of stiction. Clean oil or the proper viscosity, proper change intervals, and maintaining good oil temperatures are keys to success. Once an owner has stiction, no doubt some have obtained some good from additives. Ultimately the fix is a new injector though.

 

[Tweeder]

I have no idea of the previous owner and the maintenance, but I've done the rev-x thing since I've owned it. My local dealership is going to give me a deal on 4 injectors, stand pipes and dummy plugs for the bank at $920. So, I'll end up doing the bank.
6_Riders: good idea on swapping plugs. That will narrow down the harness without having to mess with my voltmeter.
Thanks a bunch, I may actually get to the bottom of this dang hick-up this truck developed last year.

 

[Tweeder]

For those following this,
I'm first sorry it's been a while, I see posts all the time where no resolution is mentioned so I want to make sure I don't do that.
To all those who responded to my question, thank you.

I replaced the injectors on the passenger bank, dummy plug and stand pipe and all is well. Truck runs great, no misfire, the jerking I was feeling over 50mph randomly is completely gone. Truck is running like a raped ape, and I'm even getting back up to 18.5 mpg roughly, instead of the 13 I got all last year.
Thanks again everyone.