New-to-me IDI won't start

Discussion in '6.9L IH & 7.3L IDI Diesels' started by nelstomlinson, Apr 16, 2018.

  1. nelstomlinson

    nelstomlinson Full Access Member

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    I just bought a '91 7.3L with an E4OD. The kid I bought it from said it was idling roughly and started hard when hot, but always started easily when cold. It drove fine, and started hot several times while I was testing it, so I bought it.

    I let it cool down a couple of hours, and it doesn't start, doesn't even blow smoke, doesn't even cough on starting fluid.

    Any thoughts on where I should start troubleshooting?
     
  2. steelheadguy

    steelheadguy Registered Idiot Supporting Member

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    Does it have a block heater? Plug it in, if then it starts. Must be the glow plugs.
     
  3. nelstomlinson

    nelstomlinson Full Access Member

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    The temps were above freezing, and the engine was still about body temperature, so probably not glow plugs. Even at -20F, my other IDIs will poof out smoke and then start, maybe after a whiff of ether.
     
  4. chillman88

    chillman88 Supporting Member Supporting Member

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    I'm certainly no expert, but those particular symptoms the PO described sound like a bad/dying IP to me.
     
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  5. chillman88

    chillman88 Supporting Member Supporting Member

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    Are you getting fuel from the schraeder valve on the filter head? That would be my FIRST test.
     
  6. steelheadguy

    steelheadguy Registered Idiot Supporting Member

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    Environment temperature and ether dont rule out the glowplugs. Id still try to start it with the block heater. Too simple of a test to not try.

    Last week when my plugs were still bad, the truck wouldnt start at 50 degrees F with ether. Different IDIs seem to handle different. Just because your other trucks start without plugs doesnt mean this one will.


    And yea make sure theres fuel. First at the schrader, then at each injector.
     
  7. nelstomlinson

    nelstomlinson Full Access Member

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    Checking the fuel sounds likely. Chillman, after you said that, I remembered that the kid said that the fuel gauge worked from full down to 1/2, but wouldn't go any lower. The fuel gauge is at 1/2, so it may be dry. From listening to him talk, I gather he buys his fuel $20 at a time. I'll pour in 5 gallons and check the schraeder valve.

    Steelheadguy, if I have fuel, I'll definitely try plugging in. I have an old Niehoff T52 current gauge I can hold on the glow plug wires to check for current, so I can test the glow plugs fairly easily.
     
  8. genscripter

    genscripter Full Access Member

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    My initial reaction is the same as @chillman88 's. I think it's an old IP. You should be getting some smoke no matter what, unless you are not getting fuel to your injectors, which is likely.

    But before that, exhaust all other options: First, are you getting fuel to your IP? To check that, read this: http://www.nickpisca.com/diesel/fue...-out-of-the-schroeder-valve-on-a-6-9-7-3-idi/

    If you can get constant flow from your schroeder valve, then crack your injector lines for fuel: http://www.nickpisca.com/diesel/fue...and-purge-air-on-a-6-9-7-3-idi-diesel-engine/

    If you can't get fuel to your injector lines, then it might be that your IP is garbage. The symptoms your OP said (I never believe anything OP's say, cuz they say anything to sell it) are symptoms of a tired IP.

    If the tank doesn't pull fuel after 1/2 or 1/4 tank, then you likely have the infamous "cone of failure" in the tank. To resolve that, you might need to pull your tank sender/pickup and replace it if you want a reliable and long-driving IDI.
     

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