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Surging/hesitation, white smoke till warm

Discussion in '6.9L IH & 7.3L IDI Diesels' started by Dawgust, May 22, 2020 at 4:56 PM.

Why is my truck surging and smoking?

  1. Injector pump is clogged

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    0.0%
  2. Hoses used to pick up fuel from bottom of tank are too small

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  3. Electronic lift pump

    0 vote(s)
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  4. OP should be driving an economy car and paying a mechanic

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  5. Other...

    100.0%
  6. Headgasket

    0 vote(s)
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  7. Get a job hippie

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Multiple votes are allowed.
  1. Dawgust

    Dawgust Registered User

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    Bend, OR
    Hey guys n gals. Long time listener, first time caller. Thanks for all the help that I've gotten from the collective wisdom. WE>I hehe.

    I was hoping someone could offer advice, or point me to a resource I've missed-- My 1985 F250, 6.9, 4 spd has started smoking pretty badly and "surging" on acceleration. Seems like the smoke clears once she's warmed up a bit, and surges *less* but that doesn't totally go away.

    Background-- I bypassed the mechanical lift pump with one from a chevy 6.5. (like this one)
    New (last year) tank sending units (front and rear), tank selector as well.
    Length of 1/4" lawnmower fuel hose on the bottom of the pickup in the tank to get the last 1/4 tank out of each. (with vee cutout so it won't stick to bottom of tank)

    I noticed the surging when I put the new hose lengths and pump on.

    After I ran a tank dry close to home, switched over while driving to the other, my truck died when I parked at home. Good timing! I tried to start it and it wouldn't, but it was dinner time. The next afternoon I went to start the truck and troubleshoot and it started right up. Great! But not great, no new knowledge. It drove alright, still surging though.

    The next day, it wouldn't start. Fuel pump was not pumping. Emptied the fuel out of the fuel filter/water separator. Found tiny bits of black plastic, probably what clogged the pump.

    Replaced the pump. Installed pre filter as well. I have a new fuel filter water separator to install.

    Bled air from the fuel lines and started her up.

    So! It still surges a bit, and smokes white on startup. I know that's a sign of potential headgasket failure, but this goes away after a 15 min or so of driving, although it's pretty significant until then. Coolant doesn't seem to be going away however.

    Admittedly, I am a bit of a hypochondriac, and always seem to think the ol truck is about to explode at any moment. It hasn't, and I've done quite a few long trips. All she seems to do is drink fuel and oil, so I keep her well fed.

    1.) Do you think the hose I put on the fuel pickups is too small and that is causing the surging? I guessed the hose size wrong, it was tough to fit them onto the pickups. It would be easy enough to replace them, now that I'm typing this I realize it would be easy enough to eliminate this variable.

    2.) Is it possible that plastic bits made their way past my fuel filter and into my injection pump and that's restricting fuel flow?

    Thanks in advance for all your help!
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    Cubey and Selahdoor like this.
  2. Kizer

    Kizer Supporting Member Supporting Member

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    Location:
    Denton, Texas
    Welcome to the forum.

    Use the search function to read-up on "surging" and "air intrusion"

    You'll need to isolate the intrusion.

    It could be "plugged" feed line(s) or FSV.
    My experience: 2 out of 3 "surging incidents" were air in system ...

    The 1 time that the issue was crap in the lines: I removed the rubber line on the "feed" side of pump and blew it out (about 15 PSI). I did that with the FSV in each position ... solved the problem.
     

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