2000 DT466 Odd Misfire / Shutter

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Klwjax, Aug 11, 2022.

  1. Klwjax

    Klwjax Bobtail Member

    Aug 11, 2022
    2000 DT466

    When the truck is cold it runs well, after about 15 minutes of driving once it gets warmed up we are getting a misfire with puffs of white smoke & loss of power. We pull the truck off to the side of the road and let it sit, fire it up and it will run fine again for 10-15 minutes.
    We have done oil & filter, fuel filter, priming pump, check valve ball, ICP, IPR, Cam Sensor, 6 new injectors (3 were bad so decided to do 6), new fuel lines, new ECM (other one was garbage). The truck has been driven with fuel gauges on it mechanically and on the scanner and fuel pressure is fine. It runs the same with ICP plugged in or unplugged.

    Is it possible that once the oil heats up that the HPOP is struggling to maintain pressure because it is on its way out? Or perhaps the lift pump
    Has anyone had an issue with the fuel pressure regulator on the back of the head with similar symptoms?

    If anyone has experienced this and has any suggestions they would be greatly appreciated. Thank you
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  3. Inderjit

    Inderjit Medium Load Member

    Sep 17, 2017
    When its running properly does it have any power? A weak HPOP usually causes low power and hard starting the same with a worn transfer pump. The transfer pumps do wear out over time. The fuel return check-valve will also cause low power and hard start. Has it been scanned since the ECM was replaced, are there warning lights coming on when it is acting up?
    There is a "Clean Power Harness" that connects directly to the batteries and supplies power and ground to the ECM. That harness is notorious for getting rubbed spots and corroding. Iv'e seen the several where the copper conductor was all green corrosion, I was amazed it still ran. There is a fuse in that harness in the battery box make sure its tight in its connectors. Unhook the clean power harness at the batteries and pull the harness out and inspect it. Make sure all the battery connection are good as well as grounds and at the starter as well.
    There should be a "Pass Through Connection" where the injector harness connects to the engine harness at the center left of the valve cover. when the connector bodies wear and get loose the terminals wear and can start to have compromised connections causing all kinds of running issues.
    There is a tiny metal clip that is zip tied to the harness at the cam sensor. Its there to stop the vibration causing the wires at the connector from breaking from engine vibration over time. It clips to a small metal plate near the sensor. If the clip is gone or was left unhooked the wire can fail. Take an O-ring pick and give each wire a tug, if the conductor is failing the insulation will break easily.

    Just a few ideas.
    Last edited: Aug 12, 2022
    Klwjax Thanks this.
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