Engine Brake Weak

Discussion in 'Freightliner Forum' started by Buffalo Jeff, Jul 29, 2022.

  1. Buffalo Jeff

    Buffalo Jeff Bobtail Member

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    Jul 29, 2022
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    Hi All,

    I have a new 2023 Cascadia, DD15 @ 505/1750, DT12 Transmission. Having an issue with the engine brake. Low is non existent, Mid is ok, High has no change from Mid. In both Mid and High settings at 1800 rpm only getting 12 psi of boost and very little braking feel. Been to the dealership and according to them everything is good. I’m only at 6000 miles on the truck but running in the mountains it just wants to run away on every hill. Anyone got any suggestions on what might fix the issue?
     
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  3. SWM_TECH

    SWM_TECH Light Load Member

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    Apr 15, 2018
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    As I understand the Gen 5 DD15 activates the rear solenoid for low engine braking, both front and rear solenoids for medium braking and for high braking both front and rear solenoids are activated along with EGR . Each solenoid controls 3 cylinders. It sounds like you are not getting any contribution from the rear cylinders. Can you post the last six of your VIN and did you get a description of what was done at dealership to make the determination. Seeing technician notes would be interesting, if done without naming location. I am seeing about 28 steps in troubleshooting for poor engine brake performance.
     
  4. Buffalo Jeff

    Buffalo Jeff Bobtail Member

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    Hi. VIN ends NZ0330. It’s a company truck so my notes from the dealership are limited, they basically tested it on the computer and took it for a drive around the yard and said it’s working.
     
  5. SWM_TECH

    SWM_TECH Light Load Member

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    Does your company have more than one of these 2023 Cascadia's with the same spec's? It would be nice to compare your truck with another on the same grade and load. I sure other driver's in your company come down same hills. The Gen5 DD15 has a 21 to 1 compression ratio which is higher that earlier versions, Which in my thinking should give slightly better engine braking. If you got engine faults related trouble shoot them first otherwise going through the diagnostic steps for poor engine brake performance is what I would recommend. I am certain that Detroit Diesel will be able give some guidance to dealer if they have need help solving problem. Here's the diagnostic steps for poor engine brake performance.
     

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  6. Buffalo Jeff

    Buffalo Jeff Bobtail Member

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    Thanks for the help, I’ve talked to a couple other drivers who are noticing the same thing with theirs as well (both the DD13 and DD15 new units).
     
  7. armo

    armo Light Load Member

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    Jun 16, 2022
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    you need to take off exhaust rocker arm and look for stuck actuator pistons...
    happens very often with all dd15 models.
     
  8. Antinomian

    Antinomian Road Train Member

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    I had that problem myself, but he said his is a brand new engine. I would be shocked (and pretty mad) if I had that problem on a new engine.

    BTW you don't actually have to take the rocker assembly off just to check the pins. You should be able to use an air chuck with a rubber tip in the solenoid orifice. The pins will pop out from air pressure too. The diagnostic procedure calls for 50 PSI.
     
  9. Buffalo Jeff

    Buffalo Jeff Bobtail Member

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    Well, it went back to the dealership this morning. They changed the Jake Heads and EGR valve. Test it out tonight and see how it goes.
     
  10. LoneRanger

    LoneRanger Road Train Member

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  11. Buffalo Jeff

    Buffalo Jeff Bobtail Member

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    Jul 29, 2022
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    And still not working, decent in 2nd but still no step up to 3rd stage. And 3rd stage pulls less boost then 2nd
     
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