2001 Freightliner Classic with N14 miss at idle.

Discussion in 'Freightliner Forum' started by Kruse Family Farms, Feb 1, 2023.

  1. Kruse Family Farms

    Kruse Family Farms Light Load Member

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    See the headline. N14 engine has basically all new everything about 150k ago. Including injectors. I have had it about a year. The truck sat a lot in the previous 5 or so years before I bought it. The entire time I have owned it the miss at idle has been there. Runs perfect and amazing above 1000rpm. Pulls great going down the road. No smoke out the exhaust on the miss at idle. No engine lights or codes. It has a aftermarket Davco filter housing. I can see a few bubbles in there every now and again. Am I picking up air or is that normal to see? I have never had a filter housing I can see through. I checked the cooler plate on the ECM and also looked for the fuel check valve that apparently was deleted off of my particular cooler plate. Fuel filter is changed everytime I change the oil. No Fuel leaks anywhere. Fuel flow seems fine. Plenty of power running down the road. I'm leaning towards an electrical issue? Or potentially an ECM? I know people chase their tails a lot with this issue based on other threads I have read. Any input would be greatly appreciated. Thanks in advance.
     
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  3. W923

    W923 Heavy Load Member

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    Feb 28, 2022
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    Sounds like a normal n14….maybe in person it wouldn’t be but most of the computer n14s I have been around have had a rough idle/miss but otherwise run fine. I wouldnt call it a dead miss more like one cylinder not running as hard as the rest. I have one customer who chased that idle miss and eventually sold the truck over it after several sets of injectors a wiring harness and ecm. Bottom line is I probably would just run it.
    The occasional small bubble in the Davco is also pretty normal especially if it’s been running and fuel has some air sloshed into it
     
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  4. Kruse Family Farms

    Kruse Family Farms Light Load Member

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    This has kind of been my conclusion. It is literally one cylinder isn't running the same as the rest. But everything seems to be perfectly fine. It annoys me but I think I just need to get used to it and if it ever gets worse I'll know the culprit then. I was just making sure I wasn't missing anything. I have seen tons of threads of people chasing this to no end. Injectors, ECM, pulling heads, doing multiple over head adjustments and essentially just throwing real expensive parts at them. I think I will just continue to run it. Definitely not going to sell the truck. I love it. It was what I always wanted. N14 with a 13 speed behind it.
     
  5. AModelCat

    AModelCat Road Train Member

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    A buddy had an N14 that had a goofy idle/light throttle miss. New set of injectors did nothing. Never figured it out unfortunately.
     
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  6. Kruse Family Farms

    Kruse Family Farms Light Load Member

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    Yeah I would have a hard time thinking it was an injector. It could be but these barely have any miles on them and they were put in brand new when the whole engine was overhauled. I might buy one at some point and just leave it in my truck then if one actually does go out I can throw it in. I think at this point I am just going to have to run it till something goes wrong.
     
  7. rch10007

    rch10007 Medium Load Member

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    Bump the idle up a little until it smoothes out and leave it there...
     
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  8. J.R.

    J.R. Light Load Member

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    If you add Wal-Mart 2 cyl oil 1 gal to 100-150 fuel, it seems to smooth them out. I do every fill. Little tip from wore out .
     
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  9. Kruse Family Farms

    Kruse Family Farms Light Load Member

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    Hahaha I actually did this last trip because sometimes it annoys me sitting in a dock or just warming up the truck after it has been sitting. Great tip though thanks!
     
  10. Kruse Family Farms

    Kruse Family Farms Light Load Member

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    I have heard this. I will give that a try on my next trip.
     
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  11. rch10007

    rch10007 Medium Load Member

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    Not kidding here...I had a similar issue with my N14 (525hp) celect plus. When I got a gallon low, I put in a gallon of MMO, marvel mystery oil and ran it for the next 5k miles until I noticed the oil pressure actually smoothed out. I changed the oil and it runs much smoother now. It's still not perfect becasue the idle speed (by default) is too low. I bump mine up twice. When I idle over night, I run right at 800-850. That's where the engine feels/sounds the smoothest.
     
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