12.7 white smoke at start up

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Kendall427, Jan 31, 2024.

  1. Kendall427

    Kendall427 Bobtail Member

    31
    11
    Sep 25, 2014
    miami, fl
    0
    I have a 12.7 that was rebuilt in July, ran fine for the months and out of nowhere the truck started smoking white at start up and smelled like fuel We changed the injectors and problem persisted. We also removed the head and found all the new liners scratched. Replaced the liners and pistons and reassembled and problem continued. The truck then didn’t want to run correctly, it felt like it was starving top end. Fuel pressure would drop to 35 psi. Found 1 of the Jake’s sticking Removed all there Jake’s and truck runs good again, but white smoke/fuel smell continues at start up.

    we tried another set of injectors
    Another ECM
    2 different fuel pumps
    Changed the injector wiring harness
    Replaced fuel line from pump to head
    Ran a line straight from the tank to the pump
    Check valve replace

    I am stumped
     
  2. Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.

  3. Big Road Skateboard

    Big Road Skateboard Road Train Member

    7,179
    40,701
    May 2, 2021
    0
    Did the smoke start with cold weather? Year or model#? Does it clear up when warm?

    There's only low compression or overfuel that will cause it. Some engines came with low compression pistons
     
  4. Kendall427

    Kendall427 Bobtail Member

    31
    11
    Sep 25, 2014
    miami, fl
    0
     
  5. Kendall427

    Kendall427 Bobtail Member

    31
    11
    Sep 25, 2014
    miami, fl
    0
    The engine is a 1993 series 60 12.7 Detroit . It’s sitting in a 09 Casacadia. The smoking problem started in December, at that time it looked like a freight train spitting out white smoke at start up and would go away. Now after the rebuild it smokes white at start up and heavy fuel smell, but more of a light fog … the fuel smell lingers
     
  6. Big Road Skateboard

    Big Road Skateboard Road Train Member

    7,179
    40,701
    May 2, 2021
    0
    DDEC model? Check coolant and oil temp sensor (intake temp sensor if equipped) accuracy in the ecm.
     
    Last edited: Jan 31, 2024
    Kendall427 and Rideandrepair Thank this.
  7. Kendall427

    Kendall427 Bobtail Member

    31
    11
    Sep 25, 2014
    miami, fl
    0
     
  8. Kendall427

    Kendall427 Bobtail Member

    31
    11
    Sep 25, 2014
    miami, fl
    0
    OK let me try that. Also I just went outside and the strong white smoke is back. Wish I could post a video for you to see
     
  9. Kendall427

    Kendall427 Bobtail Member

    31
    11
    Sep 25, 2014
    miami, fl
    0
  10. MRMTRANS

    MRMTRANS Medium Load Member

    409
    441
    Apr 28, 2015
    0
    I'm going on memory from 12-15 years ago: the low compression model number started with BK, I think. This # can be found below the intake manifold on the block. You might have to use steel wool and then spray with WD40 and look through a magnifying glass to see it good enough to make out the stanping. MK & PK models were higher compression, I think. I had the same problem in cold temps with a truck I used to own. Not a whole lot I could do about it. I even parked my truck in an unheated garage and plugged it in (block heater), and it still would put out a lot of white smoke compared to warmer temps.
     
    Magoo1968 and Rideandrepair Thank this.
  11. Kendall427

    Kendall427 Bobtail Member

    31
    11
    Sep 25, 2014
    miami, fl
    0
     
  • Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.