1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

6.9 sounds like it has spark knock

Discussion in '6.9L IH & 7.3L IDI Diesels' started by SuperDave, Nov 20, 2020.

  1. SuperDave

    SuperDave Registered User

    Posts:
    34
    Likes Received:
    26
    Joined:
    Mar 13, 2018
    Location:
    douglasville
    The 6.9 installed in my bronco has taken to making a spark knock sound under a load, it doesn't matter if the engine is cold or hot it makes this sound and I am assuming I need new injectors as I have already removed the valve covers and checked the upper valvetrain for any issues as well as started the engine with the covers off to make sure all the rockers were being oiled. The engine seems to run smooth, start easily and does not make any peculiar sounds at idle it also has better oil pressure than my other 2 idi's at around 25psi hot idle and 40-50psi out on the road. The reason I think injectors is until last year this engine hadn't been warm since the Clinton administration. I will also add that the engine was rebuilt right before it was parked but I don't know if the injectors were replaced or not. Thoughts?
     
  2. Farmer Rock

    Farmer Rock Registered User

    Posts:
    45
    Likes Received:
    25
    Joined:
    Oct 27, 2020
    Location:
    Glen Rock,PA
    It sounds like injectors to me.Take them to a diesel shop where they can be pop tested,and if need be,they should be able to rebuild them as well.

    Rock
     
    IDIBRONCO likes this.
  3. riphip

    riphip Supporting Member Supporting Member

    Posts:
    947
    Likes Received:
    348
    Joined:
    Nov 16, 2005
    Location:
    Memphis, TN.
    Is the throttle cable laying on/against an injector feed line??
     
  4. SuperDave

    SuperDave Registered User

    Posts:
    34
    Likes Received:
    26
    Joined:
    Mar 13, 2018
    Location:
    douglasville
    No, but I have had that happen before and it has a very similar sound, I also got the cruise control cable stuck between the air cleaner housing and intake which made a really strange sound. I'm pretty sure I have an injector that's either dripping fuel or has opening pressure that is lower than the rest but I wanted to confirm.
     
    riphip likes this.

Share This Page