Heavy Equipment Forums Heavy Equipment Community

Cat D6T fuel pressure problem

Robert Dickens · 2024-10-11 21:55

I have a D6T with 9.3L. It's blowing the fuel injector lines off the rail. It just got new injectors. I just put new rail and 1 line on because of this and it just blew another injector line off, pulled the threads off. Anyone else had this before. Thanks Rob

Replies14
  1. #1Mechanic_Caterpillar2024-10-12 01:56

    The Fuel Rail relief valve may be stuck in the closed position.

  2. #2Nige2024-10-12 06:18

    Robert, if you want some accurate information please post a machine Serial Number. There are over 30 different models of D6T, narrowing the field down would be a good idea. Were the recently-installed replacement injectors OEM or aftermarket.?

  3. #3Vetech632024-10-12 12:05

    I have a feeling they aren't OEM.

  4. #4Nige2024-10-12 12:07

    So do I.

  5. #5Robert Dickens2024-10-12 13:54

    Ser# ksb01153

  6. #6Robert Dickens2024-10-12 13:56

    Ser# KSB01153. They were OEM injectors.

  7. #7Robert Dickens2024-10-12 13:56

    Thanks

  8. #8Nige2024-10-12 15:03

    The rail pressure relief valve is #3. Did you replace that (or did it come with) the new rail that you installed.? Another option I can think of is the solenoid valves failing to control the HP pump correctly and allowing it to seriously over-pressure the system. How many total hours on the machine.? What was the reason for replacing the injectors.?

  9. #9Robert Dickens2024-10-12 15:38

    It came with new rail

  10. #10Nige2024-10-12 15:42

    Total machine hours.? And the reason the injectors were replaced.? I'm coming to the conclusion this might need ET to diagnose.

  11. #11Zac932024-10-13 15:28

    I'm not suggesting a parts cannon here but I have seen this issue on a C9.3 and after a full set of injectors, multiple lines and rails the fix was to replace the pump. But of course start simple with what is discussed above.

  12. #12Robert Dickens2024-10-14 16:55

    Almost 18,000hrs. Had 1 start leaking out the top of injector. Replaced with oem

  13. #13Nige2024-10-14 17:22

    As mentioned above by @Zac93 the suspicion regarding the HP fuel pump. If it also has 18k hours on it then it is probably for the knacker’s yard by now, as would be the rest of the engine if it is still untouched. We used to think ourselves lucky to get 12-14k out of engines in 6Ts. ET would definitely be required to check the performance/pressure of the HP pump.

  14. #14Robert Dickens2024-10-15 12:38

    Thanks. Appreciate the feedback