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P0266 code twice in month?

3K views 22 replies 3 participants last post by  beaslyb 
#1 ·
08 with less than 70k honestly don't remember exactly how many miles. It's been pretty cold here lately and I"ve had the P0266 code 2 times, I've noticed a few times with the truck in gear holding the brake it seems to "miss" a little but not all the time. Once it threw the wrench light the next time I just randomly checked the codes and it was present. I drove it today and no issues, question is I need to make a 7 hour round trip pulling an open trailer with racecar next week. Should I hold off using the truck until I can pull the valve cover and inspect/replace the injector? I damn sure would rather replace an injector before it hangs open and wipes out the #2 cylinder, any advice or is it still just way too open to say?
 
#4 ·
What kaya said...

Any time you run that truck at this point you are running the risk of hanging an injector open and costing you a motor.

Spend the 2ish grand now instead of risking $15000... Please!:please:
 
#7 ·
Sorry, that was meant as if you were going to have a shop do it.

If you are doing it yourself its pretty much just the cost of the injector and lines...


I have pretty thick skin, no offense taken :)

When you remove the injector pour some of the fuel from the rail into a clean black cap and check for sparkly things (metal...). If you don't see anything just replace the one injector and the lines. IF YOU SEE METAL that means all 8 injectors, hpfp, fuel cooler, all of the high pressure lines, hfcm, and a full flush of the low pressure lines and tank. So you don't want to see metal...
 
#8 ·
Thanks for the advice, I do all of my own work, now I'm not a "diesel mechanic" or am I able to trouble shoot them to certain extents, but I can do about anything I need to with the proper guidance. Hopefully it's just that one injector, I've done fuel filters every 10k on the mark if not before, I don't drain the water separator as often as I should but I don't skimp on maintenance either. so we'll see I have a lot going on right now so it may be a couple weeks before I can jump on it.
 
#9 ·
hopefully not base engine. not to alarm you, but these 6.4's can hide low cylinders very well. when you crank it, do you hear a flat spot in revolutions at all?
 
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#10 ·
Well I haven't noticed any flat spot, seems to run fine other then randomly it will kinda chug in gear at idle, driving it I haven't noticed it at all. I don't drive it a lot so this is all kinda new I've only driven it a few times since the first wrench light came on.
 
#11 ·
next time you go to start it, pay close attention listening for an inconsistency in starter speed
 
#12 ·
I didn't notice any difference in starter speed, I drove it about 20 miles this morning doing stuff, it runs perfect no code and no chugging in gear. I did pull the oil cap and looks to me like a lot of blowby but I'm not familiar with how much is normal on these engines. I'm going to try and post a video, I started it up later on cold again and it wasn't as much vapor so I guess next step is scanner with cylinder contribution test and see what it is.
 
#13 ·
If the oil fill cap stays in the hole when you set it in there the motor is fine. If the cap doesn't stay put you have problems...
 
#15 ·
the blow by is more so checking for poor ring sealing, or a cracked piston. however, a bent rod will not produce excess blow by but will still give you a low cylinder. i just say this because i've seen these 6.4's with bent rods so many times. but for the most part, you wouldn't even have known it by driving it. they truly are a master of disguise.
sorry. not trying to worry you lol. chances are it is just an injector. running a relative compression test would be useful for assurance here
 
#16 ·
I used a snap on scanner today and ran the cylinder contribution check on it, all cylinders stayed at 0 except #8 had a -1 at idle but with high idle it would go to 0, I'm not real familiar with this test but the prompt said a negative number was a less contributing cylinder, I'm assuming it's just an injector going out?
 
#17 ·
yea all that tells you is that there is a speed differential of the crank at the time that cyl should fire. a contribution test reads crank velocity. that's all. what you'd usually do next is run a relative compression test. if that looked good, slam an injector in. if it didn't, manual compression test
 
#19 ·
Never been a big fan of relative compression tests on 6.4s. More often then not you just get false readings.

If there is any chance of low compression just run a compression test. Its a pita, but totally doable. You just need to pull the wheel wells and yank glow plugs.
 
#20 ·
Man I hate to go through all that. But dont wanna waste $240 on an injector if there is actually trouble in that cylinder. Truck has been deleted since 20k and it has 67k on it now honestly what are the odds of actual trouble or just an injector screwing up?
 
#21 ·
yea a manual compression test is much more accurate for sure. if you want to know for certain, that's the only way. otherwise you're leaving it up to chance. i definitely wouldn't blame you if ya did though.
 
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#22 ·
Here is the deal... If you don't have excess blow by I wouldn't worry about compression just yet. I would go ahead and swap the injector with an injector balance test saying anything is off... This will give you the advantage of having the valve cover off and you can check for excessive rocker wear and other valve train related issues. Many of those issues can contribute to your one cylinder being problematic. This will also give you the chance to check the fuel rail for metal and other debris.

Chances are you just have a bad injector and there isn't much to worry about as long as it hasn't hung open yet. There is always the possibility that the hole is contributing a bit less due to wet stacking and cylinder wash down but again... If this is the case you are going to be replacing the injector anyway due to it leaking.
 
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#23 ·
I pulled the injector today, rocker arms look good, but that is the most mickey mouse setup I've ever seen, it's a wonder they make it to 100k. I may run a bore scope down in the cylinder tomorrow and see what it looks like, if all good I'll get an injector Monday and put it all back together thanks for all the advice.
 
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