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Stalling, now won't start - metering valve and....

Discussion in '6.5L Diesels' started by turbokinetic, Mar 12, 2019.

  1. turbokinetic

    turbokinetic Registered User

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    Hey folks. I am working on a 1985 Oldsmobile diesel engine. It has the DB2 pump which is so well supported here on the forum.

    I'm working on a friend's car which has been stored at my location for about 2 years. I have been driving the car every couple of months, about 20 - 30 miles each startup; and until now it has run very well.

    The car was sent here nonrunning. The previous owner damaged the engine by overheating, and then changed the IP as a troubleshooting step. Therefore, the IP appears relatively new.

    The car has been starting up instantly and running like new until the last 2 times I ran it. The first indication of any problem was the "stall upon returning to idle" issue which is commonly the metering valve getting sticky. Initially, this only occurred when the engine was fully warmed up and the A/C was off.

    It rapidly progressed to doing it no matter what, so that I had to be ready to two-foot drive it to keep the engine running.

    Last drive of the car, it was a little slow to ignite when started. Maybe 5 seconds of cranking before it ignited. After the 20 minute drive, it was running OK but still had the return-to-idle stall. I planned to use transmission oil in the filter, but work called me out.

    I went overseas for work and returned after about 2 months. The engine would not fire. I verified the ETR coil was good, and receiving power. The coil clicks audibly when powered on.

    Next, I took the top cover of the IP off, and found that the metering valve was, indeed, stuck. The housing was full of clean fuel, but the valve took considerable effort by hand to move it. There was no roughness, merely a gummed or stiff sensation.

    I removed the spin-on fuel filter and poured out the fuel. It was clean and free of water. I then refilled the filter with new Dexron transmission oil, and refitted it. Cranked the engine over until I could see the red color at the fuel return fitting of the pump. There is a solid stream of fuel from the return while cranking the engine over. Still no fuel delivery to the injectors.

    I then removed the pump cover a second time, and moved the metering valve by hand again. It became perfectly free after about 2 manual cycles.

    Again, I reassembled the pump and tried to start the engine. There was no ignition. I have loosened the injector lines on the front 3 cylinders, and there's no fuel coming out when the starter turns the engine. This is with the throttle at maximum, and while visually verifying a stream of fuel from the return.

    I don't believe the pump has seized because the transfer pump passes fuel when the engine turns over. The electric lift pump is working. There is a constant dribble of fuel while the key is ON, from the return line; which increases to a stream when the engine is cranking over.

    Any suggestions? I wonder if there is something else stuck inside the injection pump. I work on modern engines for my job, so diesels are not new to me. Just this early style pump is unfamiliar. Thanks again for any ideas.

    Sincerely,
    David
     
  2. turbokinetic

    turbokinetic Registered User

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    Well, here I am replying to myself.

    I got it running. Something in the distributor head end of the pump must have been stuck. I first tried tapping on this with a brass rod and small hammer. That didn't help.

    Then, I set up a heat gun (such as for shrinking heat-shrink tube, melting paint, etc.) to blow on the rear of the pump (the distributor head area). Left that going for 10 - 15 minutes. The pump was almost too hot to touch after that. Then, again tried cranking. Nothing. Finally, after tapping with the brass rod again, while the pump was hot, it fired a few strokes. Another tapping session, and it ran a little longer. Finally after the third tapping, it stayed running.

    Then I put a gallon of transmission oil in the tank and drove the car for about 10 miles. All of the symptoms are cured. The delayed throttle response, stalling when return to idle, stall with A/C off - all symptoms are cleared up.

    Hopefully my friend will be able to take this car home soon and it will get driven more.

    Sincerely,
    David
     
    Oledirtypearl86 likes this.
  3. Oledirtypearl86

    Oledirtypearl86 Full Access Member

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    My dad had a diesel olds and use to tell me every once in a while it needed blown out and he would take it to the Interstate and run it pretty hard till it cleared out that might help this car sounds like some power service would help this car out
     

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