N14 Cummins low oil pressure light comes on at an idle.

Discussion in 'Ask An Owner Operator' started by HighlyPossible, Jan 18, 2021.

  1. HighlyPossible

    HighlyPossible Bobtail Member

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    Need a little advise on what I should do. Low oil pressure light comes on at idle but when running down the highway low oil pressure light goes off and stays off

    this morning I pulled into simplot in Caldwell Idaho and my fuel pedal stopped responding and I had to limp it across the lot with low oil pressure light on. (Does fuel pedal response have anything to do with oil pressure?)

    I see a minor amount of oil has been leaking out of the oil pump and the oil pressure sensor port behind the fuel filter.

    Shops in the area think I need new gasket and o rings in the oil pump as well as rods , main bearing and cam bearings. Have been quoted roughly $15k. Does this sound right and should I have the work done?
     

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  3. jamespmack

    jamespmack Road Train Member

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    First install mech. Oil psi Gauge. Maybe just replace sensor. They have been known to be faulty. Second would be to replace Engine position sensor. This can actually fail and trick ecu to think it had low oil psi and cause low power/no throttle response. These are common and I normally would replace if I dont know the history of age on last sensor. However if you remove oil psi sensor on engine near ecm and mechanical gauge is low. Then inspect oil pump. Next cause could be broken oil cooler nozzles. Next would be cam bearing.

    Hope this help. Sounds like you need a shop that has more experience with a N14.
     
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  4. HighlyPossible

    HighlyPossible Bobtail Member

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    Thank you for responding! I left the truck off for about three hours and just fired it back up ; now fuel pedal and idle up toggle are working again but a check engine at next stop light is on and system diagnostic reads “engine power supply electrical fault”
    The oil pressure still reads low until I bump the idle up to above 800 rpms. Do you think I can drive it to a shop?
     

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  5. jamespmack

    jamespmack Road Train Member

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    Idk thats a tuff call. Because you don't know. Seems to be a electrical fault. Your gonna have to make that decision.
     
  6. HighlyPossible

    HighlyPossible Bobtail Member

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    Thank you. I drove to the shop with low oil pressure light on with it reading about 15-20 pounds
     
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  7. Final Drive

    Final Drive Road Train Member

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    Have the mechanics make sure your Oil pump is solid from external Oil pickup tube to internal oil pickup tube...
     
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  8. abyliks

    abyliks Heavy Load Member

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    Cummins is low pressure high volume, should be 15-20 lbs at idle and 38-40 going down the road, bypass is at 43lb

    15k is a bit much to reseal the drivers side, my shop did it in 14 hours, and did the oil pump and compressor since it all has to come off anyways, could also double check the piston coolers on the passenger side, those can effect psi

    what do you have for total miles on it? No point in doing rods and mains if you are coming up for an inframe, but rods and mains are cheap on a n14
     
  9. DUNE-T

    DUNE-T Road Train Member

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    It's the thin ecm wires on the battery. Common problem. Fix that. Then if your oil pressure is not fixed, put new sensor in and only after that get new oil pump.
     
  10. HighlyPossible

    HighlyPossible Bobtail Member

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    Took it to rays diesel in Caldwell and they connected to the ecm and oil pressure was reading 0 at idle. Guy swapped the sensor and and then it read 15 idle 40 at high rpm. Ended up getting to pick my load up and I’ve driven from Caldwell Idaho down to Vegas and it’s running great but the problem has started again.

    at low idle or coming up to a stop light low oil pressure light will come on. 800 rpms or higher light goes away

    Dropping now in Vegas and will be driving it to Phoenix Arizona today to make my second drop tomorrow morning. I am planning on doing oil pump and oil cooler nozzles for cheap insurance. Engine has approximately 1.1 million miles on it but I’d be surprised if it needs a rebuild it runs great no knocking and very little blow by
     
    Last edited: Jan 20, 2021
  11. tommymonza

    tommymonza Road Train Member

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    There is a thread on here somewhere if you search.

    It discusses the oil pickup coming loose and also the oil pump shaft spinning in the impeller if I remember right.
     
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