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7.3 PSD starts, runs, dies

Discussion in '7.3L Powerstroke Diesels' started by bbjordan, Jan 30, 2020.

  1. bbjordan

    bbjordan Snow Monkey

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    About a week ago, coming home from my daughter's place, the engine in my 1996 F250 hiccuped a couple of times. This happened when I hit a jarring bump. I thought, I'll have to keep an eye on that. Last Sunday, she asked if I could help her pick up a new 81" TV. The truck made it to the store, but I wound up having it towed home.

    Now, it'll start, run for a few seconds and die. Almost like it's out of fuel. There are no codes. Here's what I've done so far:
    Checked the fuel bowl. Full of fuel.
    Replaced the Cam Position Sensor. (I had a known good spare)
    Disconnected the fuel bowl heater.
    Tried disconnecting the ICP sensor. No change starting.
    Fuel Filter was replaced recently.

    I'm thinking now that it might be the high pressure side of the fuel pump. The fuel pump will get replaced tomorrow.
    I'll probably clean up the under valve cover connector too. It's quite a mess in the valley.

    Do you guys have any ideas? Am I on the right track?

    Here's a video of it:

     
  2. bbjordan

    bbjordan Snow Monkey

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    Here's another video. This one was actually before the other one.

     
  3. 79jasper

    79jasper Chickenhawk

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    Have you pulled any data?


    Sent from my SM-N960U using Tapatalk
     
  4. bbjordan

    bbjordan Snow Monkey

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    From what I usually monitor, everything looks normal.
    Revs,HPOP, InjPW, IPR. I'll have to check to see if it saved the logs. There were no codes.

    Too bad Navistar didn't put a fuel pressure sensor on the 7.3. I should put my own on.
     
    IDIoit likes this.
  5. 79jasper

    79jasper Chickenhawk

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    Then I would start with it being a fuel supply problem.

    Sent from my SM-N960U using Tapatalk
     
  6. greenskeeper

    greenskeeper Full Access Member

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    when it starts, does it act like it is running on 4 cylinders? In the video when you raise the idle speed are you giving it a lot of pedal with little response? If so it's probably a faulty UVCH
     
  7. bbjordan

    bbjordan Snow Monkey

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    greenskeeper, when it runs it seems like it's running on all 8.
     
  8. bbjordan

    bbjordan Snow Monkey

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    Began to replace the fuel pump today,and when I went to loosen the banjo bolt at the back or the pump, I noticed it was loose! Aha, that explains why I was smelling diesel lately. I tightened it up thinking that must surely be the problem. Nope, same thing: start, run for a bit, die. Dang!

    So, out came the old pump...and fuel bowl.

    P_20200131_165759_p.jpg

    Close up of the nastiness:
    P_20200131_165754_p.jpg

    After cleanup:
    P_20200131_175642_p.jpg

    New pump in (so shiny :D ). Note the big wrench on the banjo bolt. Not much room there:
    P_20200131_181415.jpg

    Well, that's it for today. It's getting late, and i'm getting cold and tired. I got a late start on this project because I had to do some shopping, and play taxi driver for my grand daughter.

    Tomorrow I hope to get the fuel bowl cleaned up and installed. Good thing I had some hose for the fuel bowl that I picked up a couple years ago
     
  9. greenskeeper

    greenskeeper Full Access Member

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    Was the fuel bowl full when you removed it?

    Have you checked the IPR nut? If that backs off it can give wacky performance.

    If it still stalls out after the new fuel pump. The next time is stalls remove the inspection plug of the HPOP and see if the is oil no further and an inch from the top.
     
  10. bbjordan

    bbjordan Snow Monkey

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    Fuel bowl cleaned up and installed. I just beat the rain and snow. :p Still the same issue; starts, runs, and then dies. It's almost like I just turned the key off.
    I even put in a new fuel filter. Yes, I know I should have done that first. :)

    IPR nut is securely fastened.
     
  11. lotzagoodstuff

    lotzagoodstuff Supporting Member Supporting Member

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    How old is the ignition switch?
     
  12. greenskeeper

    greenskeeper Full Access Member

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    When it stalls, is it the roughly the same time every time? Did you check the oil level in the HPOP after it stalls out? The oil should be no less than an inch from the top when looking through the inspection plug on level ground. If the oil is lower then it could be the LPOP or pickup tube.
     
  13. IDIoit

    IDIoit MachinistFabricator Supporting Member

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    the last time I had this issue, I gave up and sent it to the dealer, turned out to be the IPR itself
     
  14. bbjordan

    bbjordan Snow Monkey

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    Good question. When I got the truck, it had two different keys. One to get in the truck and one for the ignition. It is possible that the steering column had been replaced in the past.

    One other thing that probably has nothing to do with this issue, but the cruise control does not work. All the bulbs are good so...

    Tomorrow, I'll check the HPOP oil level.
     
  15. bbjordan

    bbjordan Snow Monkey

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    So, I tried to get the plug off of the HPOP reservoir. It did not want to come out. I stopped short of stripping it out. Doh!

    I did swap out the 30 amp fuses and relays for the IDM and PCM. It was cold out (-7C) and not plugged in, but it fired right up. I jumped out to check the engine, and as soon as the door closed, the truck died.

    I have a sinking feeling that this is an intermittent wiring problem. Sigh...

    It's times like this that I really appreciate my IDI.
     

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